admin at asarian-host
Feb 27, 2004, 11:39 PM
Post #15 of 16
----- Original Message -----
From: <mw-list-srs-discuss [at] csi>
To: <srs-discuss [at] v2>
Sent: Friday, February 27, 2004 8:15 PM
Subject: Re: [srs-discuss] A problem with SRS
> More generally, but with a slight abuse of language: SRS demands
> that every relay becomes bidirectional.
The argument seems, that one becomes not an open relay, because a spammer
cannot forge SRS1 an address which will also produce a valid SRS0 address.
But why relay at all? An open relay is simply this: "A host which, barring
local .forward functionality, relays mail to non-local recipients, from
non-authorized IP space." SRS1 falls into that category. If you send me a
valid SRS0 address, wrapped in a valid SRS1 recipient, then I am an open
relay; because I allow you, from an unauthorized IP space, to use my (E)SMTP
mailers to send mail to non-local recipients.
I am no SRS1 forwarding host; and plan not to become one, either. :) I
accept SRS1 addresses, when they resolve to valid, local SRS0 recipients;
that's all. To that effect, I even compiled a disclaimer into sendmail:
<<< 220-asarian-host.net ESMTP + SPF Sendmail 8.12.11/8.12.11; ...
<<< 220- Effective immediately: Asarian-host may no longer accept
<<< 220- connections from IP addresses which have no rDNS
<<< 220- (PTR record) assigned.
<<< 220- Effective immediately: Asarian-host no longer accepts
<<< 220- DSN recipients without valid SRS signature.
<<< 220 N.B. Asarian-host is no SRS1 forwarding host.
>>> EHLO asarian-host.net
<<< 250-asarian-host.net Hello localhost [127.0.0.1], pleased to meet you
<<< 250-SIZE 6291456
<<< 250-AUTH LOGIN PLAIN DIGEST-MD5 CRAM-MD5
<<< 250-X-SRS 0
<<< 250 HELP
Since SPF and SRS are essentitally SMTP Service Extensions, I also compiled
in two RFC1869 4.3 compliant SMTP Service Extensions:
<<< 250-X-SRS 0
The second one says: "I do SRS0, but I am no SRS1 forwarding host." A
forwarder, like pobox, for instance, might respond:
<<< 250-X-SRS 0 1
I know this, and the extended error codes, are probably not exactly on
people's list of highest priorities. Still, I think these matters deserve
some attention too.
System Administrator Asarian-host.org
"If you were supposed to understand it,
we wouldn't call it code." - FedEx
To unsubscribe, change your address, or temporarily deactivate your subscription,
please go to http://v2.listbox.com/member/?listname=srs-discuss [at] v2