1 Jul
2004
1 Jul
'04
9:26 a.m.
Hi,
a while back, we had quite some discussion about blocking of port 25
traffic by ISPs.
If you look at last night's Slashdot article "Comcast Port 25 Blocks
Result In Less Spam", I guess you'll understand better why ISPs do
such a thing - and that it is indeed a good thing (tm).
Greets Eric
1 Jul
1 Jul
9:54 a.m.
a while back, we had quite some discussion about
blocking of port 25
traffic by ISPs.
If you look at last night's Slashdot article "Comcast Port 25 Blocks
Result In Less Spam", I guess you'll understand better why ISPs do
such a thing - and that it is indeed a good thing (tm).
If the ISP doesn't put this on the homepage and on the FAQ and the
hotline doesn't know anything about it, it is a really bad, bad thing,
believe me!
My girlfriend had to send several important mails for her project this
day. It wasn't fun. At first I thought it was the fault of the mail
provider. If I had been informed by the ISP I could have found an
alternative (perhaps by connecting my old analog modem).
It's really NASTY. I lost a LOT of time. Only by testing with telnet
(port 25) the connection to other SMTP servers I knew of, I could rule
out that it was the fault of my mail provider. But for this you need to
have a list of several SMTP servers at hand!!!
There is absolutely NO point in protecting this behavior. Port 25 is
(after port 80) the most important port one needs. Blocking it means to
deliver not the service that I have paid for!
The next time you buy a car and the factory has forgotten to put an
engine in it, I will say that it is a good thing, because an engine
would pollute the environment (a ressource we are more dependend of than
the network!)
Patrick Kaell
11:39 a.m.
Hi,
On Thu, 1 Jul 2004, Patrick Kaell wrote:
They should inform about this kind of measure, of course.
a while back,
we had quite some discussion about blocking of port 25
traffic by ISPs.
If you look at last night's Slashdot article "Comcast Port 25 Blocks
Result In Less Spam", I guess you'll understand better why ISPs do
such a thing - and that it is indeed a good thing (tm).
If the ISP doesn't put this on the homepage and on the FAQ and the
hotline doesn't know anything about it, it is a really bad, bad thing,
believe me! My girlfriend had to send several important mails for
her project this
day. It wasn't fun. At first I thought it was the fault of the mail
provider. If I had been informed by the ISP I could have found an
alternative (perhaps by connecting my old analog modem).
Care to explain just why you didn't follow the only sensible
measure, which is to go through your ISPs mailserver, which
*must* relay for you?
If you're on dialup, there's absolutely no reason to do it
any other way - and if you had a valid reason, wtf are you
doing on a dialup line with no fixed IP?
Also, there's a great many mailservers that are filtering
based on DULs, i.e. if you're on a dialup, there's quite
some chances that your emails won't be accepted at the other
end anyway.
Hmm deja vu somehow - it's a repeat of the discussion we
already had.
[snip]
There is absolutely NO point in protecting this
behavior. Port 25 is
(after port 80) the most important port one needs. Blocking it means to
deliver not the service that I have paid for!
No, you weren't using the service correctly, IMHO. And you haven't
read your ISPs terms of use, probably.
You probably also haven't ever had the "luck" of handling a larger
network's abuse@ account.
Your ISP offers an email service - which goes through it's mailserver.
They deliver - it's not the ISPs problem that you didn't use the
service properly.
I'd also say that they offer due diligence - protecting everybody
else from misconfigured mailservers (open relays), from zombies
(think trojans exploited by spammers) etc. on their network - I
consider that a good thing.
[I'll add a remark that I've encountered quite some admins who
can't properly configure a mailserver - so it's definitely not
something I want to see done and put on the 'net by Mr. anybody,
when I have to bear the consequences of that incompetence.]
The next time you buy a car and the factory has
forgotten to put an
engine in it, I will say that it is a good thing, because an engine
would pollute the environment (a ressource we are more dependend of than
the network!)
Invalid comparison. I'd see it rather as an airbag on the driver's
side which you can't switch off [hint: there's no reason to want an
off switch there, although there are good reasons to have it for
the other seat].
Greets Eric
6:06 p.m.
Eric Dondelinger wrote:
Care to explain just why you didn't follow the
only sensible
measure, which is to go through your ISPs mailserver, which
*must* relay for you?
I do not whant to change my E-Mail address everytime I change my dialup
provider. If they relay everything, even non coditel addresses, then
please tell me the security advantage? You mean that they must relay
everything from me no matter what's in the From and To field!!!??? Is
this what you mean by security??? Every decent worm would find the
necessary information in the mail client's config files immediately. And
it would be a nice relay service for spammer who uses the ISP's dialup!!
If you're on dialup, there's absolutely no
reason to do it
any other way - and if you had a valid reason, wtf are you
doing on a dialup line with no fixed IP?
Why on earth do you think that *every* mail provider (GMX, Web.de,
Puretec, ... offer a SMTP service????
I use a authentificated (ESMTP) SMTP protocol to send my mail. This
doesn't work over a simple relay who doesn't know all accounts that
exists on earth.
Also, there's a great many mailservers that are
filtering
based on DULs, i.e. if you're on a dialup, there's quite
some chances that your emails won't be accepted at the other
end anyway.
Let's repeat. I do do send it directly. I use port 25 (as every other
internet user) to communicate with my mail provider! SMTP and port 25 is
*not* only used between mail servers, *but* also between sending mail
clients and their SMTP server!!!!!!!!!!!!
No, you weren't using the service correctly,
IMHO. And you haven't
read your ISPs terms of use, probably.
Yes I read everything. Ok?
Please, I got not an AOL account where I can access Mail and WWW. I got
a full TCP/IP access to the internet!!!
You probably also haven't ever had the
"luck" of handling a larger
network's abuse@ account.
I do get attacked every 2 seconds by an windows worm. If you want I can
send you my firewall log! Those don't get blocked by the provider of
course!!!
Your ISP offers an email service - which goes through
it's mailserver.
They deliver - it's not the ISPs problem that you didn't use the
service properly.
You mean by paying for a TCP/IP access I should not use TCP/IP as it was
intended for???? TCP/IP is there to connect computers over a worldwide
network. This is not Minitel, BTX, Teletext and so on!
I'd also say that they offer due diligence -
protecting everybody
else from misconfigured mailservers (open relays), from zombies
(think trojans exploited by spammers) etc. on their network - I
consider that a good thing.
If they had blocked unauthentificated SMTP traffic. Ok, then I would
perhaps agree. But blocking everything, INCLUDING THEIR OWN MAILSERVER,
IS NOT OK!!!!!
[I'll add a remark that I've encountered
quite some admins who
can't properly configure a mailserver - so it's definitely not
something I want to see done and put on the 'net by Mr. anybody,
when I have to bear the consequences of that incompetence.]
EVERY MAIL CLIENT USES SMTP. SEE ABOVE!!!!
Invalid comparison. I'd see it rather as an
airbag on the driver's
side which you can't switch off [hint: there's no reason to want an
off switch there, although there are good reasons to have it for
the other seat].
Please, the next time you tell me that there is no reason to send mail
and that I should use the telephone, right????
I have 5 years experience with mail servers, know the SMTP protocol, the
sendmail.cf file and already have worked for an ISP!!!
But Codidel has seen that it was a mistake and has reopened port 25 for
their own mailserver after a day and for every other mailserver after 4
days!!!
Patrick Kaell
8:55 p.m.
Hi,
first off - after your flood of mails - I can see that indeed you
may have more of an idea about SMTP & consorts than most.
I'll add that I'm responsible for some mail servers myself, and I
actually have read RFCs. And no, I'm no shareholder of any ISP,
and the only thing I'm defending is prevention of the disastrous
effects of worms.
On Thu, 1 Jul 2004, Patrick Kaell wrote:
Maybe so that spammers can easily open up an account, use it
for a spam run, and forget it afterwards? It's not like GMX,
web.de & Co do a thorough job of verifying the data you provide
them when opening up an account...
Using a company mailserver that way would make more sense.
Ok, I now see what you mean. To get rid of traffic generated by
worms, but let through authenticated SMTP, the ISP could not
use a simple packet filter then, but would have to pipe the
traffic through an application-level firewall. Doable, but
less simple to set up - and more error prone.
Having a packet filter tie in with a sort of mailserver white
list - hmm... less realistic.
Still, normal procedure is to use the ISP's mailserver for
outgoing mail, and access the mail provider's server through
POP3/IMAP/whatever to retrieve your mail.
Sorry if I formulated that a bit harshly.
See above - many people actually want that kind of filtering.
I can't say I blame them.
Many ISPs will at least block NetBIOS traffic.
Hmm... you said it above yourself - look at your firewall logs.
Those logs are precisely the result of the lack of security out
there. If ISPs did filter by default, and open up specific ports
on demand by individual users, things would look much much better.
Really, this isn't the Internet of 10 years ago. Keeping everything
wide open for everybody would IMO be highly irresponsible. It's
totally illusory to think just anybody could properly secure his/
her internet access, when even way too many supposed "experts"
manage to totally botch even simple stuff.
Totally open lines still exist - leased lines normally are not
subject to any kind of filtering. Prices of course are very
different from dial-up style lines. And you'll still get slammed
in case of abuses (if your ISP doesn't react right away, he will
do so when his own upstream swings the bat).
Ah, I can see you're talking about Coditel's ... erm... I guess
fuck-up is the only term that fits.
I'm not talking about that kind of error. Of course they can't
block their own mailserver for their own clients.
I know perfectly well. And every normally set up mail client
sends their mail through the ISPs mailserver. Using other mail
servers, even through smtp-auth, is not usual.
Calm down. Of course I'm not saying something stupid like that.
All I'm saying is, there's normally no reason not to go through
your ISPs mailserver. I know there can be special needs - which
may have other solutions though.
Eric Dondelinger wrote:
Why should you have to change your email address?
Care to explain just why you didn't follow
the only sensible
measure, which is to go through your ISPs mailserver, which
*must* relay for you?
I do not whant to change my E-Mail address everytime I change my dialup
provider. If they relay everything, even non coditel addresses,
then
please tell me the security advantage?
Where lies security in checking a From: field?
There are very many good reasons not to use an email address
that wasn't given to you by your dial-up provider, it would
be rather stupid for the ISP to force a customer to use only
one specific domain. *that* would be very poor customer service.
I've got LuxDSL. I constantly send mail from here with other
domains than pt.lu. mailsvr.pt.lu relays it for me - as I'm
on the P&T network. As you know about SMTP servers, I'll just
say "smarthost".
You mean that they must relay
everything from me no matter what's in the From and To field!!!???
Of course! You're on his network, he knows who you are - the
moment you're dialing in! If you abuse the service, bye bye
your account, and chances are you'll hear from the ISPs lawyers
or at least from their billing service.
Is
this what you mean by security???
There is no security in checking To: and From: fields (i.e. the
mail's body). There's not even much point in checking the
envelope From:. That's for the case of users *on the ISPs network*.
Every decent worm would find the
necessary information in the mail client's config files immediately. And
it would be a nice relay service for spammer who uses the ISP's dialup!!
See above for the spammer case - ISPs worth their name (I now there's
black sheep) don't take kindly to spammers.
As for worms - I haven't seen any so far that didn't try to use
SMTP directly, but went through the ISP's mail relay.
It is a shame though that ISPs don't routinely warn customers
having infected PCs though and/or cut their service until they
have made sure their PCs are clean - I now of at least one large
one that will do so after a couple of complaints/warnings.
If you're
on dialup, there's absolutely no reason to do it
any other way - and if you had a valid reason, wtf are you
doing on a dialup line with no fixed IP?
Why on earth do you think that *every* mail provider (GMX, Web.de,
Puretec, ... offer a SMTP service???? I use a authentificated (ESMTP) SMTP protocol to send
my mail. This
doesn't work over a simple relay who doesn't know all accounts that
exists on earth.
Indeed, authenticated SMTP can help there - it would be a grave
mistake for such a setup to accept plain SMTP (open relay, as it
would be trivial to fake the domain part).
I still don't see a point in going to an external service -
unless your ISPs mail server is extremely unreliable, which
would be a reason to find another ISP.
Also,
there's a great many mailservers that are filtering
based on DULs, i.e. if you're on a dialup, there's quite
some chances that your emails won't be accepted at the other
end anyway.
Let's repeat. I do do send it directly. I use port 25 (as every other
internet user) to communicate with my mail provider! SMTP and port 25 is
*not* only used between mail servers, *but* also between sending mail
clients and their SMTP server!!!!!!!!!!!! No, you
weren't using the service correctly, IMHO. And you haven't
read your ISPs terms of use, probably.
Yes I read everything. Ok? Please, I got not an AOL account where I can access
Mail and WWW. I got
a full TCP/IP access to the internet!!!
You do realise though that for most people, such settings actually
make sense? Many even are crying out loud for more traffic filtering
by ISPs.
You probably
also haven't ever had the "luck" of handling a larger
network's abuse@ account.
I do get attacked every 2 seconds by an windows worm. If you want I can
send you my firewall log! Those don't get blocked by the provider of
course!!! Your ISP
offers an email service - which goes through it's mailserver.
They deliver - it's not the ISPs problem that you didn't use the
service properly.
You mean by paying for a TCP/IP access I should not use TCP/IP as it was
intended for???? TCP/IP is there to connect computers over a worldwide
network. This is not Minitel, BTX, Teletext and so on! I'd also
say that they offer due diligence - protecting everybody
else from misconfigured mailservers (open relays), from zombies
(think trojans exploited by spammers) etc. on their network - I
consider that a good thing.
If they had blocked unauthentificated SMTP traffic. Ok, then I would
perhaps agree. But blocking everything, INCLUDING THEIR OWN MAILSERVER,
IS NOT OK!!!!! [I'll add
a remark that I've encountered quite some admins who
can't properly configure a mailserver - so it's definitely not
something I want to see done and put on the 'net by Mr. anybody,
when I have to bear the consequences of that incompetence.]
EVERY MAIL CLIENT USES SMTP. SEE ABOVE!!!! Invalid
comparison. I'd see it rather as an airbag on the driver's
side which you can't switch off [hint: there's no reason to want an
off switch there, although there are good reasons to have it for
the other seat].
Please, the next time you tell me that there is no reason to send mail
and that I should use the telephone, right???? I have 5 years experience with mail servers, know the
SMTP protocol, the
sendmail.cf file and already have worked for an ISP!!!
Brothers in arms, in that case [even if the place I'm working now
isn't exactly an ISP].
But Codidel has seen that it was a mistake and has
reopened port 25 for
their own mailserver after a day and for every other mailserver after 4
days!!!
I had heard about that first part - that can only be described as
a serious fuck-up, everybody will agree.
I had not heard as yet that they restored outgoing TCP 25 traffic
to anywhere - is this also for the dynamic IP ranges, or only for
the static IPs? There was some difference there IIRC.
Greets Eric
9:46 p.m.
Eric Dondelinger wrote:
No, spammers do not do this. They definitely do not use @gmx.net, etc.
sender addresses. The addresses are almost always faked, only the DNS
part exists. Spammer nowadays use infected PCs to send mails directly to
the recipient. As I understand you correctly, their infected PCs will
use mailsvr.pt.lu in the future if they have infected a PT customer,
right? (just as an example, they *will* find the hostname in the mail
client's config files, be it mailsvr.pt.lu or something else).
I've got LuxDSL. I constantly send mail from here
with other
domains than pt.lu. mailsvr.pt.lu relays it for me - as I'm
on the P&T network. As you know about SMTP servers, I'll just
say "smarthost".
Now, mail coming from mailsvr.pt.lu do not need to be from a @pt.lu
address, right? It can be @sex.com and so on? Until now it was enough to
block dialup address ranges in a Black List. Now it is neccessary to add
mailsvr.pt.lu to the Black List, to be protected? A worm on your PC can
send a mail to anybody using anybody's mail address using mailsvr.pt.lu.
And the worm does not need to be ultrasmart to find the hostname
mailsvr.pt.lu in the config files of your mail client.
Of course! You're on his network, he knows who
you are - the
They do not know that the mail address you are using is yours. Only the
mail provider does know this.
moment you're dialing in! If you abuse the
service, bye bye
your account, and chances are you'll hear from the ISPs lawyers
or at least from their billing service.
For this you don't need to block port 25. Logging would be sufficient.
You will take away the account of everybody who is invected and who
sends nonsense through mailsvr.pt.lu? At least if the worm would send
directly through port 25 to the recipient's mail server, the recipient
could block it by finding the dialup IP address in the Black List!!!
There is no security in checking To: and From: fields
(i.e. the
mail's body). There's not even much point in checking the
envelope From:. That's for the case of users *on the ISPs network*.
Sure. My provider's mail servers only accepts mails from addresses which
exists on their server. And they are on a white list and can be trusted
which can't definitely not be said for mailsvr.pt.lu anymore!
Why on earth do
you think that *every* mail provider (GMX, Web.de,
Puretec, ... offer a SMTP service????
Maybe so that spammers can easily open up an account, use it
for a spam run, and forget it afterwards? It's not like GMX,
web.de & Co do a thorough job of verifying the data you provide
them when opening up an account...
Using a company mailserver that way would make more sense. Indeed, authenticated SMTP can help there - it would
be a grave
mistake for such a setup to accept plain SMTP (open relay, as it
would be trivial to fake the domain part).
I still don't see a point in going to an external service -
unless your ISPs mail server is extremely unreliable, which
would be a reason to find another ISP.
To protect Black List protected mail servers against you (see above).
Still, normal procedure is to use the ISP's
mailserver for
outgoing mail, and access the mail provider's server through
POP3/IMAP/whatever to retrieve your mail.
This is rather unconventional. Never heard this!
Hmm... you said it above yourself - look at your
firewall logs.
Those logs are precisely the result of the lack of security out
there. If ISPs did filter by default, and open up specific ports
on demand by individual users, things would look much much better.
Really, this isn't the Internet of 10 years ago. Keeping everything
wide open for everybody would IMO be highly irresponsible. It's
totally illusory to think just anybody could properly secure his/
her internet access, when even way too many supposed "experts"
manage to totally botch even simple stuff.
Totally agree!
I know perfectly well. And every normally set up mail
client
sends their mail through the ISPs mailserver. Using other mail
servers, even through smtp-auth, is not usual.
No, see above.
>I have 5 years experience with mail servers, know
the SMTP protocol, the
>sendmail.cf file and already have worked for an ISP!!!
I have patched (yes I am a C programmer) gnu-pop3d to implement SMTP
after POP3 with sendmail for our customers. Nobody used the SMTP service
of the dialup provider. This was 2000-2001. So I know the szene.
Patrick Kaell
2 Jul
2 Jul
6:44 a.m.
Hi,
On Thu, 1 Jul 2004, Patrick Kaell wrote:
That's true. P&T does not know I have an account @linux.lu, they
don't know I have one with @vis.ethz.ch, or some @gmx.net.
They still know who connected when, got which IP address, sent
mail via their server - if they receive complaints, their client
will get his/her head washed.
You'd have to to quite some logging to be able to differentiate
whether the traffic were legitimate or not. Certainly enough to
make any "Datenschuetzer" cringe.
You're now talking *receiving* mails I assume. I was only talking
about *sending*. Two different pairs of shoes.
If really you're talking about sending - how would you want to
implement that on mailservers relaying for a number of different
organizations, with no chance of ever getting access to the
complete user database?
No, spammers do not do this. They definitely do not use @gmx.net, etc.
sender addresses. The addresses are almost always faked, only the DNS
part exists. Spammer nowadays use infected PCs to send mails directly to
the recipient.
Correct, so far. zombies make for 80% of spam (at least until
before the Comcast story). Most of the remaining goes via open
relays, maybe some formmail scripts etc.
I'm not sure I understand what you're saying here.
Say what? I've seldom seen it any other way.
Hmm. NACK.
If you know the scene, I'm *really* surprised you haven't seen
that kind of setup.
I propose continuing the discussion around a beer keg. It'll be
more fun, and simpler to avoid misunderstandings.
Greets Eric
Eric Dondelinger wrote:
That's about the idea. I actually use it for @linux.lu, @vis.ethz.ch.
I sure don't use it for my @pt.lu, which is a spam-only account.
I've got LuxDSL. I constantly send mail from
here with other
domains than pt.lu. mailsvr.pt.lu relays it for me - as I'm
on the P&T network. As you know about SMTP servers, I'll just
say "smarthost".
Now, mail coming from mailsvr.pt.lu do not need to be from a @pt.lu
address, right? It can be @sex.com and so on? Until now it was enough to
block dialup address ranges in a Black List. Now it is neccessary to add
mailsvr.pt.lu to the Black List, to be protected?
Of course not. It relays mail coming from P&T networks, and it
will accept mail for @pt.lu accounts. That's it. That's what
it's supposed to do.
If it accepted to relay mail from anybody to anybody else, then
it would be an open relay, and would merit a blacklist entry.
But that's not what it does.
A worm on your PC can
send a mail to anybody using anybody's mail address using mailsvr.pt.lu.
I don't know any worm that will look up your outgoing mail server
settings and send itself out via that machine. I'll be happy to
learn about such worms.
And the worm does not need to be ultrasmart to find
the hostname
mailsvr.pt.lu in the config files of your mail client.
I agree it would probably be trivial to implement, I've just not
seen it anywhere.
Of course!
You're on his network, he knows who you are - the
They do not know that the mail address you are using is yours. Only the
mail provider does know this. moment
you're dialing in! If you abuse the service, bye bye
your account, and chances are you'll hear from the ISPs lawyers
or at least from their billing service.
For this you don't need to block port 25. Logging would be sufficient. You will take away the account of everybody who is
invected and who
sends nonsense through mailsvr.pt.lu?
Those would get warned to clean up their mess. Repeat offenders
cut off until the mess is actually cleaned.
Spammers would get a harsher treatment.
I still have to say that I've rarely seen luxembourgish spam - half
a dozen or so in several years. There was one quite evil one among
those, which claimed to have a ministerial ok... the ministry didn't
appreciate, and took appropriate measures.
At least if the worm would send
directly through port 25 to the recipient's mail server, the recipient
could block it by finding the dialup IP address in the Black List!!!
That's what's being done now, via DULs.
There is no
security in checking To: and From: fields (i.e. the
mail's body). There's not even much point in checking the
envelope From:. That's for the case of users *on the ISPs network*.
Sure. My provider's mail servers only accepts mails from addresses which
exists on their server. And they are on a white list and can be trusted
which can't definitely not be said for mailsvr.pt.lu anymore!
mailsvr.pt.lu does know (AFAIK) the users having @pt.lu addresses
(maybe others, I dont't know). I'm quite sure it won't accept
mails coming from the outside if it's not defined as the MX for
the target domain. If it did, it would be an open relay.
Why on earth do you think that *every* mail provider
(GMX, Web.de,
Puretec, ... offer a SMTP service????
Maybe so that spammers can easily open up an account, use it
for a spam run, and forget it afterwards? It's not like GMX,
web.de & Co do a thorough job of verifying the data you provide
them when opening up an account...
Using a company mailserver that way would make more sense. As I understand you correctly, their infected PCs
will
use mailsvr.pt.lu in the future if they have infected a PT customer,
right? (just as an example, they *will* find the hostname in the mail
client's config files, be it mailsvr.pt.lu or something else).
In the future maybe. Not at this point, AFAIK.
Also, if the server implements AV software, a worm spreading
via mail would be simple to stop at that point (minus AV update
delay).
Indeed,
authenticated SMTP can help there - it would be a grave
mistake for such a setup to accept plain SMTP (open relay, as it
would be trivial to fake the domain part).
I still don't see a point in going to an external service -
unless your ISPs mail server is extremely unreliable, which
would be a reason to find another ISP.
To protect Black List protected mail servers against you (see above). Still, normal
procedure is to use the ISP's mailserver for
outgoing mail, and access the mail provider's server through
POP3/IMAP/whatever to retrieve your mail.
This is rather unconventional. Never heard this! I know
perfectly well. And every normally set up mail client
sends their mail through the ISPs mailserver. Using other mail
servers, even through smtp-auth, is not usual.
No, see above. >I have 5
years experience with mail servers, know the SMTP protocol, the
>sendmail.cf file and already have worked for an ISP!!!
I have patched (yes I am a C programmer) gnu-pop3d to implement SMTP
after POP3 with sendmail for our customers. Nobody used the SMTP service
of the dialup provider. This was 2000-2001. So I know the szene. 
24 Jul
24 Jul
7:30 p.m.
Brent, back from Spain, and probably out of sync:
Patrick Kaell a écrit :
Eric Dondelinger wrote:
Eric is right: "mail coming from mailsvr.pt.lu do not need to be from a
@pt.lu address". Plan-Net has customers using also EPT mail servers, and
I confirm this works. The protection you have is that EPT closes access
to e-mail services to customers emitting large amount of e-mails. I
don't know how they detect it, but they indeed switch off e-mail
forwarding services to identified customers that are suspected to have
e-mail worms or are abusing the e-mail service (spamming). I had a
customer complaining to Plan-Net about this, and it was verified as
being done by EPT. They even send an e-mail to the customer to ask him a
cleaning of his computer before requesting the re-opening of his e-mail
service.
That's how it works right now, and I think it's not so bad. For sure,
it's not the silver-bullet against spams, but who has that silver bullet ???
--
Brent Frère
Private e-mail: Brent(a)BFrere.net
Postal address: 5, rue de Mamer
L-8280 Kehlen
Grand-Duchy of Luxembourg
European Union
Mobile: +352-021/29.05.98
Fax: +352-26.30.05.96
Home: +352-307.341
URL: http://BFrere.net
I've got LuxDSL. I constantly send mail from
here with other
domains than pt.lu. mailsvr.pt.lu relays it for me - as I'm
on the P&T network. As you know about SMTP servers, I'll just
say "smarthost".
Now, mail coming from mailsvr.pt.lu do not need to be from a @pt.lu
address, right? It can be @sex.com and so on? Until now it was enough
to block dialup address ranges in a Black List. Now it is neccessary
to add mailsvr.pt.lu to the Black List, to be protected? A worm on
your PC can send a mail to anybody using anybody's mail address using
mailsvr.pt.lu. And the worm does not need to be ultrasmart to find the
hostname mailsvr.pt.lu in the config files of your mail client.
9:37 p.m.
Brent Frère wrote:
Brent, back from Spain, and probably out of sync:
Patrick Kaell a écrit :
I think there may still be confusion about this. I know that this works.
(As you can see in the last posts, I already looked at the headers of
some mails on this list to see that EPT relays everything coming from
their own network). I was only sarcastic. I have no problem with the
technical understanding of this. I just have a problem seeing why this
method actually should be superior. Nobody could explain this to me yet.
Thibaut Britz sent a mail on 3 July on this list through ETH's SMTP
server with a '(a)yahoo.com' From address to prove something I already
know. What he doesn't know is that even if ETH's SMTP server happily
relays such stuff, many receiver's servers will drop it *immediately*.
Look at a large freemailer in Germany: GMX. They drop everything whith
'(a)aol.com' and '(a)yahoo.com' From addresses that were not sent through
AOL's or Yahoo's SMTP servers. You may think that this may be harsh...
But look at:
http://www.theregister.co.uk/2004/07/05/sender_authentication/
Caller ID goes in the same direction. Sending throught your ISP's mail
server may work now, but it will dissapear just like 'open relays'.
Eric Dondelinger wrote:
Eric is right: "mail coming from mailsvr.pt.lu do not need to be from a
@pt.lu address". Plan-Net has customers using also EPT mail servers, and I've got LuxDSL. I constantly send mail from
here with other
domains than pt.lu. mailsvr.pt.lu relays it for me - as I'm
on the P&T network. As you know about SMTP servers, I'll just
say "smarthost".
Now, mail coming from mailsvr.pt.lu do not need to be from a @pt.lu
address, right? It can be @sex.com and so on? Until now it was enough
to block dialup address ranges in a Black List. Now it is neccessary
to add mailsvr.pt.lu to the Black List, to be protected? A worm on
your PC can send a mail to anybody using anybody's mail address using
mailsvr.pt.lu. And the worm does not need to be ultrasmart to find the
hostname mailsvr.pt.lu in the config files of your mail client. I confirm this works. The protection you have is that
EPT closes access
to e-mail services to customers emitting large amount of e-mails. I
don't know how they detect it, but they indeed switch off e-mail
forwarding services to identified customers that are suspected to have
e-mail worms or are abusing the e-mail service (spamming). I had a
customer complaining to Plan-Net about this, and it was verified as
being done by EPT. They even send an e-mail to the customer to ask him a
cleaning of his computer before requesting the re-opening of his e-mail
service.
I understand this. Again, *why* is this method superior? Any packet
filter can do the same. A ISP can log connections to port 25 and calculate:
a. The number of connections made to port 25
b. The number of connections to different IP addresses to port 25
c. The overall traffic to port 25
If somebody misuses and sends bulk mail, the ISP will see it thanks to
the packet filter. Advanced packet filters like Checkpoint-1 even can
look into the payload of IP packets and reassemble them. Then, you can
even log the SMTP headers. Even iptables can do this in a more
rudimentary way. Why should one be forced to use the ISP's SMTP server?
It is even a step backward if you consider that 'Caller ID' with SPF is
the future.
That's how it works right now, and I think
it's not so bad. For sure,
it's not the silver-bullet against spams, but who has that silver bullet
Sure, the silver-bullet *exists*. It is just not implemented on the mail
servers around the world. The sender sends his mail over his mail
provider's mail server using ASMTP (authenticated SMTP) or SMTP over SSL
(Mozilla, Eudora, Outlook, ... support both methods). The reciepient
recieves the mail from the sender's mail server and checks thanks to
'Caller ID' if the mail has been sent throught the 'right' relay.
Today 'Caller ID' with SPF is optional. As soon as 60% of the mail
servers support this, the other 40% will come into increased pressure to
implement this as well, if the do not want to take the risk to be
classified as spam.
The software is ready. Mail clients support everything which is
necessary. Mail server software is also ready, just look in the header
of the mails coming from this list. You will see that the mailing list
server of linux.lu aleady supports SPF.
Greetings, Patrick Kaell
1 Jul
1 Jul
11 p.m.
hi,
let me just quickly add my 2c.
it is absolutely _NOT_ uncommon for users to _NOT_ use their ISP's mailserver
for outgoing mails.
and please don't say such things as providers should block all ports by
default and only open some upon request!
what is that for a view of freedom huh ?
i mean, you use a service and you are supposed to know their terms and policy.
and you are supposed to know what possible danger you are exposing yourself if
you get connected.
now you should manage yourself to protect yourself or use software supplied by
your provider for that purpose.
it is not a good thing at all if your provider just blocks every connex not
having been initiated by you.
and i hope it won't be like that in the any near future.
disabling port 25 is a bad thing.
and it won't prevent spammers from spamming.
you know, there are many ports right?
spam is a annoying, but you own't reduce it by such means IMHO.
first off - after your flood of mails - I can see that
indeed you
may have more of an idea about SMTP & consorts than most.
I'll add that I'm responsible for some mail servers myself, and I
actually have read RFCs. And no, I'm no shareholder of any ISP,
and the only thing I'm defending is prevention of the disastrous
effects of worms.
On Thu, 1 Jul 2004, Patrick Kaell wrote:
Maybe so that spammers can easily open up an account, use it
for a spam run, and forget it afterwards? It's not like GMX,
web.de & Co do a thorough job of verifying the data you provide
them when opening up an account...
Using a company mailserver that way would make more sense.
Ok, I now see what you mean. To get rid of traffic generated by
worms, but let through authenticated SMTP, the ISP could not
use a simple packet filter then, but would have to pipe the
traffic through an application-level firewall. Doable, but
less simple to set up - and more error prone.
Having a packet filter tie in with a sort of mailserver white
list - hmm... less realistic.
Still, normal procedure is to use the ISP's mailserver for
outgoing mail, and access the mail provider's server through
POP3/IMAP/whatever to retrieve your mail.
Sorry if I formulated that a bit harshly.
See above - many people actually want that kind of filtering.
I can't say I blame them.
Many ISPs will at least block NetBIOS traffic.
Hmm... you said it above yourself - look at your firewall logs.
Those logs are precisely the result of the lack of security out
there. If ISPs did filter by default, and open up specific ports
on demand by individual users, things would look much much better.
Really, this isn't the Internet of 10 years ago. Keeping everything
wide open for everybody would IMO be highly irresponsible. It's
totally illusory to think just anybody could properly secure his/
her internet access, when even way too many supposed "experts"
manage to totally botch even simple stuff.
Totally open lines still exist - leased lines normally are not
subject to any kind of filtering. Prices of course are very
different from dial-up style lines. And you'll still get slammed
in case of abuses (if your ISP doesn't react right away, he will
do so when his own upstream swings the bat).
Ah, I can see you're talking about Coditel's ... erm... I guess
fuck-up is the only term that fits.
I'm not talking about that kind of error. Of course they can't
block their own mailserver for their own clients.
I know perfectly well. And every normally set up mail client
sends their mail through the ISPs mailserver. Using other mail
servers, even through smtp-auth, is not usual.
Calm down. Of course I'm not saying something stupid like that.
All I'm saying is, there's normally no reason not to go through
your ISPs mailserver. I know there can be special needs - which
may have other solutions though.
--
regards,
Georges Toth
Eric Dondelinger wrote:
Why should you have to change your email address?
Care to explain just why you didn't follow
the only sensible
measure, which is to go through your ISPs mailserver, which
*must* relay for you?
I do not whant to change my E-Mail address everytime I change my dialup
provider. If they relay everything, even non coditel
addresses, then
please tell me the security advantage?
Where lies security in checking a From: field?
There are very many good reasons not to use an email address
that wasn't given to you by your dial-up provider, it would
be rather stupid for the ISP to force a customer to use only
one specific domain. *that* would be very poor customer service.
I've got LuxDSL. I constantly send mail from here with other
domains than pt.lu. mailsvr.pt.lu relays it for me - as I'm
on the P&T network. As you know about SMTP servers, I'll just
say "smarthost".
You mean that they must relay
everything from me no matter what's in the From and To field!!!???
Of course! You're on his network, he knows who you are - the
moment you're dialing in! If you abuse the service, bye bye
your account, and chances are you'll hear from the ISPs lawyers
or at least from their billing service.
Is
this what you mean by security???
There is no security in checking To: and From: fields (i.e. the
mail's body). There's not even much point in checking the
envelope From:. That's for the case of users *on the ISPs network*.
Every decent worm would find the
necessary information in the mail client's config files immediately. And
it would be a nice relay service for spammer who uses the ISP's dialup!!
See above for the spammer case - ISPs worth their name (I now there's
black sheep) don't take kindly to spammers.
As for worms - I haven't seen any so far that didn't try to use
SMTP directly, but went through the ISP's mail relay.
It is a shame though that ISPs don't routinely warn customers
having infected PCs though and/or cut their service until they
have made sure their PCs are clean - I now of at least one large
one that will do so after a couple of complaints/warnings.
If
you're on dialup, there's absolutely no reason to do it
any other way - and if you had a valid reason, wtf are you
doing on a dialup line with no fixed IP?
Why on earth do you think that *every* mail provider (GMX, Web.de,
Puretec, ... offer a SMTP service???? I use a authentificated (ESMTP) SMTP protocol to
send my mail. This
doesn't work over a simple relay who doesn't know all accounts that
exists on earth.
Indeed, authenticated SMTP can help there - it would be a grave
mistake for such a setup to accept plain SMTP (open relay, as it
would be trivial to fake the domain part).
I still don't see a point in going to an external service -
unless your ISPs mail server is extremely unreliable, which
would be a reason to find another ISP.
Also,
there's a great many mailservers that are filtering
based on DULs, i.e. if you're on a dialup, there's quite
some chances that your emails won't be accepted at the other
end anyway.
Let's repeat. I do do send it directly. I use port 25 (as every other
internet user) to communicate with my mail provider! SMTP and port 25 is
*not* only used between mail servers, *but* also between sending mail
clients and their SMTP server!!!!!!!!!!!! No, you
weren't using the service correctly, IMHO. And you haven't
read your ISPs terms of use, probably.
Yes I read everything. Ok? Please, I got not an AOL account where I can
access Mail and WWW. I got
a full TCP/IP access to the internet!!!
You do realise though that for most people, such settings actually
make sense? Many even are crying out loud for more traffic filtering
by ISPs.
You
probably also haven't ever had the "luck" of handling a larger
network's abuse@ account.
I do get attacked every 2 seconds by an windows worm. If you want I can
send you my firewall log! Those don't get blocked by the provider of
course!!! Your ISP
offers an email service - which goes through it's mailserver.
They deliver - it's not the ISPs problem that you didn't use the
service properly.
You mean by paying for a TCP/IP access I should not use TCP/IP as it was
intended for???? TCP/IP is there to connect computers over a worldwide
network. This is not Minitel, BTX, Teletext and so on! I'd
also say that they offer due diligence - protecting everybody
else from misconfigured mailservers (open relays), from zombies
(think trojans exploited by spammers) etc. on their network - I
consider that a good thing.
If they had blocked unauthentificated SMTP traffic. Ok, then I would
perhaps agree. But blocking everything, INCLUDING THEIR OWN MAILSERVER,
IS NOT OK!!!!!
[I'll add a remark that I've encountered quite some admins who
can't properly configure a mailserver - so it's definitely not
something I want to see done and put on the 'net by Mr. anybody,
when I have to bear the consequences of that incompetence.]
EVERY MAIL CLIENT USES SMTP. SEE ABOVE!!!! Invalid
comparison. I'd see it rather as an airbag on the driver's
side which you can't switch off [hint: there's no reason to want an
off switch there, although there are good reasons to have it for
the other seat].
Please, the next time you tell me that there is no reason to send mail
and that I should use the telephone, right???? I have 5 years experience with mail servers, know
the SMTP protocol, the
sendmail.cf file and already have worked for an ISP!!!
Brothers in arms, in that case [even if the place I'm working now
isn't exactly an ISP].
But Codidel has seen that it was a mistake and
has reopened port 25 for
their own mailserver after a day and for every other mailserver after 4
days!!!
I had heard about that first part - that can only be described as
a serious fuck-up, everybody will agree.
I had not heard as yet that they restored outgoing TCP 25 traffic
to anywhere - is this also for the dynamic IP ranges, or only for
the static IPs? There was some difference there IIRC.
Greets Eric
_______________________________________________
Lilux-help mailing list
Lilux-help(a)lilux.lu
http://lilux.lu/mailman/listinfo/lilux-help
2 Jul
2 Jul
6 a.m.
Hi,
no need to do a TOFU, you know?
On Fri, 2 Jul 2004, Georges Toth wrote:
and please don't say such things as providers
should block all ports by
default and only open some upon request!
what is that for a view of freedom huh ?
Guess what, @work we have a few dialup lines, normal users of
these have only a very few "standard" ports open towards the
internal network. The only ones having access to "any" are
administrators. No-one ever complained about this. Not a single
user (of more than a couple hundred).
Your normal internet-surfing 0815 guy will not need much more
than DNS, FTP, HTTP, and SMTP via the ISP mailserver - maybe
some high ports for stuff like chat, p2p, streaming media.
That's exactly the kind of use I'm talking about.
People that actually use other stuff - say, SSH - are rather
rare. Those relatively clued users could for instance be
accomodated by a filter adaptable through some webinterface.
I know this is problematic for an ISP. For companies, this
is standard policy.
i mean, you use a service and you are supposed to know
their terms and policy.
and you are supposed to know what possible danger you are exposing yourself if
you get connected.
now you should manage yourself to protect yourself or use software supplied by
your provider for that purpose.
That's the current status, indeed. Fact is, it doesn't work out
very well. "firewall logs"!
it is not a good thing at all if your provider just
blocks every connex not
having been initiated by you.
and i hope it won't be like that in the any near future.
You may not notice it, but many an ISP already routes HTTP traffic
through a transparent proxy. Many an ISP blocks NetBIOS. Many an
ISP has blocked ports to avoid SQL Slammer. etc.
If you are using dialup lines, chances are very high that you do
not have unfiltered access.
disabling port 25 is a bad thing.
It's not "disabled". With the discussed blocking of outbound
SMTP traffic except for the ISP mailserver, email still works.
For the larger organizations I know of (granted, that's more
of a company setting, not ISP), everyone denies outbound SMTP
traffic except from the company mailserver.
and it won't prevent spammers from spamming.
Of course. It still will block a great many options for those
spammers. Namely zombies, which make for 80% of spam these days.
you know, there are many ports right?
Sure. But those pesky mailservers usually listen on port 25 only.
spam is a annoying, but you own't reduce it by
such means IMHO.
Have you checked out that article about Comcast. Them alone to
implement such a policy has for many people reduced incoming
spam by 50%!
Greets Eric
1:20 p.m.
no need to do a TOFU, you know?
which means?
Guess what, @work we have a few dialup lines, normal
users of
these have only a very few "standard" ports open towards the
internal network.
it's a different story whether we talk about work or isp.
Your normal internet-surfing 0815 guy will not need
much more
than DNS, FTP, HTTP, and SMTP via the ISP mailserver - maybe
some high ports for stuff like chat, p2p, streaming media.
That's exactly the kind of use I'm talking about.
right. but because of those joe users, others should have everything blocked
as well?
wow kewl...
People that actually use other stuff - say, SSH - are
rather
rare.
think so?
Those relatively clued users could for instance be
accomodated by a filter adaptable through some webinterface.
i don't think so.
i rather think that IF they start blocking everything, they will do so and
nothing else.
so no webinterface, and no exceptions.
it would be a great idea if they would block everything and then give you
access to a webinterface and let you do what you want (open everything, some,
none). but i doubt something like that would happen....
I know this is problematic for an ISP. For companies,
this
is standard policy.
it's normal for companies... i tottaly agree. but that's different from an
isp.
i mean, you
use a service and you are supposed to know their terms and
policy. and you are supposed to know what possible danger you are
exposing yourself if you get connected.
now you should manage yourself to protect yourself or use software
supplied by your provider for that purpose.
That's the current status, indeed. Fact is, it doesn't work out
very well. "firewall logs"! disabling port
25 is a bad thing.
It's not "disabled". With the discussed blocking of outbound
SMTP traffic except for the ISP mailserver, email still works. For the larger organizations I know of (granted,
that's more
of a company setting, not ISP), everyone denies outbound SMTP
traffic except from the company mailserver.
company != isp
you know,
there are many ports right?
Sure. But those pesky mailservers usually listen on port 25 only.
1:51 p.m.
Hi,
On Fri, 2 Jul 2004, Georges Toth wrote:
"Text Oben Fullquote Unten" - bad form.
I know, we already had the discussions about proper quoting
a couple of weeks ago ;-)
Indeed. It's still something that IMHO would accomodate most
normal users. I know perfectly well that the people participating
in this discussion do not belong into that category.
As a default setting, that wouldn't be so bad.
Yes. One of these days I'll go sniffing some traffic on the
backbone here - I'll see about producing stats about the
protocols used. Even though it's a somewhat special environment,
it should be close to the typical use.
That's your assumption. I explicitly proposed that exception
mechanism.
Indeed. Still, if it makes sense for a company, it's worth really
thinking about whether it wouldn't at least partially also make
sense for an ISP.
so what?
it's not that hard to install that stupid little free firewall which does a
pretty godd job.
there are many free firewalls out there.
sygate, zonealarm, to only count 2 of the best (i talk about windoze...).
Hmm... check out http://www.linkblock.de - especially the
links regarding so-called "personal firewalls".
While Felix von Leitner's way of putting things may be a bit
crude, there's certainly truth in it.
In short: they aren't worth much, many worms/viruses will get
around them and disable them.
so IT IS BLOCKED!
i don't want to access my isp mail. i want to access other servers on the
inet.
so that way, 25 _WOULD BE_ blocked for me.
or am i wrong?
You can send mail to other mailservers - through your ISP's
mailserver. So no, you're not blocked.
True. Question is still, wouldn't the same sort of setup make
sense.
right.
imagine setting up a spam relay which listens on port 3132.
what you do now with blocking 25?
oops.
No oops. Even if the zombies listen on other ports (hint: they
do!), they still need to send to port 25 - as long as they try
sending their ware directly, no luck.
Greets Eric
no need to do
a TOFU, you know?
which means? Guess what,
@work we have a few dialup lines, normal users of
these have only a very few "standard" ports open towards the
internal network.
it's a different story whether we talk about work or isp. Your normal
internet-surfing 0815 guy will not need much more
than DNS, FTP, HTTP, and SMTP via the ISP mailserver - maybe
some high ports for stuff like chat, p2p, streaming media.
That's exactly the kind of use I'm talking about.
right. but because of those joe users, others should have everything blocked
as well?
wow kewl... People that
actually use other stuff - say, SSH - are rather
rare.
think so? Those
relatively clued users could for instance be
accomodated by a filter adaptable through some webinterface.
i don't think so.
i rather think that IF they start blocking everything, they will do so and
nothing else. so no webinterface, and no exceptions.
it would be a great idea if they would block everything and then give you
access to a webinterface and let you do what you want (open everything, some,
none). but i doubt something like that would happen....
Well, it's certainly something I could live with - essentially,
it would be a user-configurable firewall service, hopefully with
sanity checks included (too easy to get things very wrong).
I know this is
problematic for an ISP. For companies, this
is standard policy.
it's normal for companies... i tottaly agree. but that's different from an
isp. i mean, you use a service and you are supposed to know
their terms and
policy. and you are supposed to know what possible danger you are
exposing yourself if you get connected.
now you should manage yourself to protect yourself or use software
supplied by your provider for that purpose.
That's the current status, indeed. Fact is, it doesn't work out
very well. "firewall logs"! disabling port 25 is a bad thing.
It's not "disabled". With the discussed blocking of outbound
SMTP traffic except for the ISP mailserver, email still works. For the larger
organizations I know of (granted, that's more
of a company setting, not ISP), everyone denies outbound SMTP
traffic except from the company mailserver.
company != isp you know, there are many ports right?
Sure. But those pesky mailservers usually listen on port 25 only.
24 Jul
24 Jul
7:53 p.m.
Georges Toth a écrit :
>Your normal internet-surfing 0815 guy will not need
much more
>than DNS, FTP, HTTP, and SMTP via the ISP mailserver - maybe
>some high ports for stuff like chat, p2p, streaming media.
>That's exactly the kind of use I'm talking about.
>
>
>People that actually use other stuff - say, SSH - are rather
>rare.
>
>
Maybe confusion between web access and Internet access here... People
that want web access can go to AOL, but if I purchase an INTERNET
access, I demand full access to all IP services, including the one I
will create !
BTW, I tryed recently the httptunnel package, that enables the build of
VPNs or port forwarning through http proxies. Works fine for me. Maybe
this is a solution to access ANY service even behind a web-only access
through a web proxy...
Just my 0.2 eurocent...
--
Brent Frère
Private e-mail: Brent(a)BFrere.net
Postal address: 5, rue de Mamer
L-8280 Kehlen
Grand-Duchy of Luxembourg
European Union
Mobile: +352-021/29.05.98
Fax: +352-26.30.05.96
Home: +352-307.341
URL: http://BFrere.net
1 Jul
1 Jul
6:21 p.m.
No, you weren't using the service correctly,
IMHO. And you haven't
read your ISPs terms of use, probably.
The best would be to block every port??? If communication between
clients and servers are bad for mail, this must also be true for WWW?
Let's block port 80! This would be the ultimate security solution for
you! But nobody would pay for a service like this! Bad for shareholders
like you ;-)
Patrick Kaell
24 Jul
24 Jul
6:20 p.m.
Brent, back from holliday and trying to process its huge mail queue:
A ISP that blocks port 25 forces you indeed to use its mail service. It
is as Belgacom that since some years blocked access to luxembourish EPT
information service (was +352017 in old times, other number I don't
remember by heart now) from its own network, so that you have to use its
International inquiries service, that is extreamly expensive.
This is forced sales, and supress customer freedom of choice for the
provision of Internet-based services. Why not an ISP that blocks access
to banking services, forcing you to open a bank account at a bank
service this ISP owns and operates ? Why not blocking of search engines
like Google or Yahoo, forcing you to pass though the ISP's operated
search engine, that will become soon a billed value added service ?
For me, provision of an Internet access means provision of an IP address
and no control on it. Other services (web hosting, mail hosting,
firewall, anti-spam, ...) must remain optional service and not a forced
service sale. If we accept port 25 being filtered, then we will go
progressively to a limited Internet-like service, like AOL.
By the way, are there no ISPs yet that limit access to the Internet to
port 80 and 443 only ?
As soon as their is no more anonymous Internet access, the authorities
can enforce anti-spam laws by using records of ISPs that give
correspondance between IP address/time of use and address of the user. I
think this should be enough violation of privacy. We don't need in
addition a restriction to our freedom of choice of supplier.
Just my 0.5 eurocent.
Eric Dondelinger a écrit :
--
Brent Frère
Private e-mail: Brent(a)BFrere.net
Postal address: 5, rue de Mamer
L-8280 Kehlen
Grand-Duchy of Luxembourg
European Union
Mobile: +352-021/29.05.98
Fax: +352-26.30.05.96
Home: +352-307.341
URL: http://BFrere.net
My girlfriend
had to send several important mails for her project this
day. It wasn't fun. At first I thought it was the fault of the mail
provider. If I had been informed by the ISP I could have found an
alternative (perhaps by connecting my old analog modem).
Care to explain just why you didn't follow the only sensible
measure, which is to go through your ISPs mailserver, which
*must* relay for you?
If you're on dialup, there's absolutely no reason to do it
any other way - and if you had a valid reason, wtf are you
doing on a dialup line with no fixed IP?
Also, there's a great many mailservers that are filtering
based on DULs, i.e. if you're on a dialup, there's quite
some chances that your emails won't be accepted at the other
end anyway.
1 Jul
1 Jul
6:11 p.m.
What I want to add:
ESMTP (authentificated SMTP) and SMTP over SSL *IS* the solution, *NOT*
blocking a service everybody needs!
I simply don't understand *why* you are defending this attitude. A
attitude even Coditel now sees as wrong. Are you a shareholder???
Patrick Kaell
5 Jul
5 Jul
5:46 p.m.
On Thu, 2004-07-01 at 20:11, Patrick Kaell wrote:
I simply don't understand *why* you are defending
this attitude. A
attitude even Coditel now sees as wrong. Are you a shareholder???
Please calm down.
Personal attacks do not help at all.
--
----------------------------------------------------------------------
Serge Marelli, Luxembourg
E-mail : serge.marelli(a)linux.lu
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LiLux, Luxembourg LUG : http://www.linux.lu/
Defending Innovation against Patent Inflation http://swpat.ffii.org/
7:40 p.m.
Serge Marelli wrote:
On Thu, 2004-07-01 at 20:11, Patrick Kaell wrote:
I do not think that a shareholder is something negative. Even a
shareholder of Coditel. I still recommend Coditel to many people even
after the port 25 issue.
I know that I was emotional and that I wasn't always fair. I already
wrote that in my post from 2.7.2004 18:54
You just have to read the posts you missed ;-)
Greetings, Patrick Kaell
I simply don't understand *why* you are
defending this attitude. A
attitude even Coditel now sees as wrong. Are you a shareholder???
Please calm down.
Personal attacks do not help at all.
1 Jul
1 Jul
8:19 p.m.
a while back, we had quite some discussion about
blocking of port 25
traffic by ISPs.
If you look at last night's Slashdot article "Comcast Port 25 Blocks
Result In Less Spam", I guess you'll understand better why ISPs do
such a thing - and that it is indeed a good thing (tm).
It might be a good practice to read at least the summary of the article
you are referring to. Additionally posting the URL would be a good idea,
so that the list members can also read the article.
It says:
[ they decided to identify spammers and zombie relays on their network
and block port 25 traffic from those IP addresses ]
So, they block only the spammers and zombie relays and *not* EVERYBODY!
Here is the URL of the slashdot article:
http://yro.slashdot.org/article.pl?sid=04/06/30/1759209&mode=thread&…
Imagine the police arresting *every* honest citizen, only because there
might be criminals amongst them ;-)
Patrick Kaell
5 Jul
5 Jul
5:39 p.m.
On Thu, 2004-07-01 at 11:26, Eric Dondelinger wrote:
Hi,
a while back, we had quite some discussion about blocking of port 25
traffic by ISPs.
If you look at last night's Slashdot article "Comcast Port 25 Blocks
Result In Less Spam", I guess you'll understand better why ISPs do
such a thing - and that it is indeed a good thing (tm).
Blocking might have been a good idea...
- not telling users/customers in advance
- not documenting it
- not mentionning it on their website
- denying it on the phone and helpline
- not foreseeing that some customers might have problems and preparing
the hotline for it
et caetera
that's just worse than lousy and more than sucks
--
----------------------------------------------------------------------
Serge Marelli, Luxembourg
E-mail : serge.marelli(a)linux.lu
----------------------------------------------------------------------
LiLux, Luxembourg LUG : http://www.linux.lu/
Defending Innovation against Patent Inflation http://swpat.ffii.org/
7238
days inactive
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days old
20 comments
5 participants
participants (5)
-
Brent Frère -
Eric Dondelinger -
Georges Toth -
Patrick Kaell -
Serge Marelli