[Lilux-help] port 25 blocking by ISPs

[Brent Frère]

Brent, back from Spain, and probably out of sync:

Patrick Kaell a écrit :

> Eric Dondelinger wrote:
>
>> 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.

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 at BFrere.net

Postal address: 5, rue de Mamer
                L-8280 Kehlen
                Grand-Duchy of Luxembourg
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Mobile: +352-021/29.05.98
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URL:    http://BFrere.net

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