[Lilux-help] e-mail problems using Coditel-cable ISP

[Georges Toth]

hi,

i'm using coditel as well, and "I" can confirm that everything works as 
usual!!!
i don't use the coditel mail service, i use other smtp servers.
and those work and have never stoped from working.

you seem to have some other problem, OR coditel is blocking that port on you 
both?
but i don't see why they should do that....

On Friday 28 May 2004 07:53, Patrick LEMMERS wrote:
> Hi,
> I can confirm, for the last few days Coditel has been blocking outgoing
> connection to port 25 to ANY machine !!!
> Since this morning they are at least allowing connections to their
> official  smtp relay (smtp.coditel.net) ...... Well done guys !!!
>
> It looks like they are trying to force their users to use only their
> mail server for outgoing mail .... :-(
>
> a+
> Patrick.
>
> On Thu, 2004-05-27 at 16:50, Eric Dondelinger wrote:
> > Hi Serge,
> >
> > > For the past 4 weeks there have been increasing problems, first my
> > > mails seemed to be rejected by Sendar for some obscure "IP forwarding"
> > > question and Thierry helped me with that.  I had to fix my parameters
> > > in Ximian Evolution and Kmail (I'm using both, yes, different e-mail
> > > adresses, different "identities", different repositories etc...)
> >
> > ?? Sounds strange. -v please (maybe at the meeting tonight)
> >
> > > The last time I was able to send myil from my normal account was on
> > > Sunday night, since then all I get is some error message saying "unable
> > > to connect to sendar port 25".
> >
> > Try this:
> > (as root), run tcpdump
> > (as anyone), telnet sendar.prophecy.lu 25
> > Check the tcpdump - you'll see the outgoing packets from your machine
> > to sendar, you should also see the replies coming. If nothing comes
> > back (not even ACKs), chances are your traffic is being dropped on
> > the way - question is where.
> >
> > Oh yes, if the telnet works, you'll see this:
> > bash-2.05b$ telnet sendar.prophecy.lu 25
> > Trying 213.166.63.242...
> > Connected to sendar.prophecy.lu.
> > Escape character is '^]'.
> > 220-sendar.prophecy.lu ESMTP Sendmail 8.12.10 ready at Thu, 27 May 2004
> > 16:50:02 +0200
> > 220 No Spam please!
> >
> > (close via "quit")
> >
> >
> > Also try this (as root):
> > nmap -p 25 sendar.prophecy.lu
> > You should get:
> > root # nmap -p 25 sendar.prophecy.lu
> >
> > Starting nmap 3.50 ( http://www.insecure.org/nmap/ ) at 2004-05-27 16:32
> > CEST Interesting ports on sendar.prophecy.lu (213.166.63.242):
> > PORT   STATE SERVICE
> > 25/tcp open  smtp
> >
> > If it says filtered instead of open, again, we'll know packets are
> > being dropped on the way. If it says closed, the packets are not
> > dropped but rejected.
> >
> > > I _am_ able to retrieve my mails from Sendar though and I do receive
> > > e-mails on each of my e-mail adresses.
> >
> > Different port...
> >
> > > I called Thierry and we checked a few things and it doesn't seem to
> > > come from Sendar, so I called the Coditel (un)help-line to inquire.  As
> > > usual they at first considered I might have problems with Outlook or
> > > perhaps a trojan on my system, I explained that neither Kmail, nor
> > > Evolution, nor Linux are all that suscpetible to windows virii (they
> > > were actually understanding about that) and said there have been
> > > "several" reports of users having trouble sending e-mail, they were
> > > surprised though that I _am_ able to send e-mail with my Coditel
> > > account (surprise, this works)
> >
> > ... which I assume you're sending via the Coditel mailserver?
> >
> > Note: whatever mail you're sending out, you're _always_ supposed
> > to go through your ISP's mailserver. If you're trying to deliver
> > mail directly, chances are that the recipient's mailserver will
> > see your IP as belonging to a DUL (dial-up list), and thus refuse
> > to talk to you (as much spam comes from dialups, be that analog,
> > ISDN, dsl or cable).
> > A From: (or envelope Mail From:) is easily forged, so if the
> > server allows you to send mail based on that only, it's to be
> > considered an open relay. If it uses pop-before-smtp or smtp-auth,
> > things look better.
> >
> > Now, when trying the above - get Thierry to have a tcpdump
> > running on his firewall (I bet there must be one ;-)) to see
> > whether the packet arrives there. Give him your IP address
> > first, so he can filter directly for your traffic. A short
> > phone call will make sure it's no problem on TC's end.
> >
> > > 3) Sendar responds to ping, but I can't ssh to Sendar either, might be
> > > similar filtering from Coditel, how can I investigate this?
> >
> > IMHO that would fit the bill.
> >
> > > 4) any other suggestions
> >
> > Ask Coditel whether they are filtering traffic. Ask them whether
> > they block outbound SMTP traffic (unless going through their
> > mailserver - this makes a lot of sense, considering all the mail
> > resp. Outlook viruses as well as spam), ask them whether they
> > filter anything else, whether they force your HTTP traffic
> > through a proxy etc.
> >
> > I can very much symphathize with them if they are filtering
> > outbound SMTP traffic (I'm seriously considering this measure
> > @work), I can understand if they use a web proxy, I very much
> > understand if they drop ports 137-139 traffic (SMB), but they
> > certainly should bloody leave alone an SSH port (22).
> >
> > Note, I can symphatize/understand this, but if they do it, they
> > should inform their customers, and offer their clued customers (tm)
> > [not that there are many] a way around this. Personally, I wouldn't
> > accept such a castrated internet connection (and lord, do I sometimes
> > hate the one at work, where I'm in charge of the filtering myself ;-)).
> >
> > Greetings, Eric
> >
> > _______________________________________________
> > Lilux-help mailing list
> > Lilux-help at lilux.lu
> > http://lilux.lu/mailman/listinfo/lilux-help

-- 

regards,
Georges Toth