[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Asrg] 6. Proposals: MTA MARK vs port 25 filtering?
On Sun, Dec 14, 2003 at 11:13:03AM -0500, Daniel Feenberg wrote:
> Perhaps you are confused by lax terminology. When anti-spammers speak of
> filtering port 25, they mean packets destined to port 25 on the remote
> system. That is the only port that accepts mail from strangers on most
> systems.
If you start to block port 25 outgoing people will start to make wide
use of SRV records, because a lot of receiving MTAs will /want/ to
talk to users behind port 25 blocked networks.
With SRV records you don't need well-known ports any longer, but you
specify the port your SMTP speaking MTA is listening on in the SRV
record itself.
Port 25 blocking rendered useless.
\Maex
--
SpaceNet AG | Joseph-Dollinger-Bogen 14 | Fon: +49 (89) 32356-0
Research & Development | D-80807 Muenchen | Fax: +49 (89) 32356-299
"The security, stability and reliability of a computer system is reciprocally
proportional to the amount of vacuity between the ears of the admin"
_______________________________________________
Asrg mailing list
Asrg@ietf.org
https://www1.ietf.org/mailman/listinfo/asrg