nanog mailing list archives

Re: RBL-type BGP service for known rogue networks?


From: woods () weird com (Greg A. Woods)
Date: Mon, 10 Jul 2000 11:10:35 -0400 (EDT)


[ On Monday, July 10, 2000 at 09:26:28 (-0400), Shawn McMahon wrote: ]
Subject: Re: RBL-type BGP service for known rogue networks?

None of which are the case here.

Agreed.

However I should have listed the other requirement that I thought was
self-obvious since we're talking about SMTP here.  I.e. I don't ever
accept e-mail from anything less than the most strictly conforming SMTP
implementations.  You're violating part one of RFC 1123 section #5.2.5.
The name given by your SMTP server in the HELO "MUST" be a canonical
hostname.  It must not be a CNAME.

To bend the meaning a bit, as Postfix says, "503 polite people say hello
first".

The case here is that eiv.com is under my control, but the reverse lookup
for the address is not.

No problem.

My hostname is not forged, it's legitimate and it resolves to my proper
IP address via RFC-compliant means.  If you lookup oa.eiv.com you'll resolve
the IP unless your DNS is seriously broken.

Indeed it does.

        $ host -t a oa.eiv.com
        oa.eiv.com              CNAME   eiv.myip.org
        eiv.myip.org            A       209.26.240.172

Unfortunately as you can see it goes through a CNAME first and that
means it's illegal to use in an SMTP HELO greeting (or as an NS target).
Why you do this nonsensical mapping in the first place is beyond me.
Either do your own dynamic DNS yourself and declare a proper A record
and be done with it, or just announce as eiv.myip.org and forget it.
The name will only appear in a Received header and it'll usually be
accompanied by the name given in the in-addr zone anyway so I really
don't understand why you're trying to break SMTP for this reason.

To even suggest that ADSL through the only available provider isn't enough
of a "real" connection for a home user, and that they should instead get
a T1 or something, is beyond ridiculous.

Boy do you ever read the wrong things into other peoples words a lot!

Since when does "real connection" equal ADSL, T1 or whatever!?!?!?!?

I had a *real* connection over 28.8Kbps for several years!  A real
Internet connection has nothing to do with bandwidth and everything to
do with network numbers and routing.  My cable modem is much faster but
it is not a real Internet connection (even though it does have a static
IP#!).  The tunnel through it is "real" though....  :-)

-- 
                                                        Greg A. Woods

+1 416 218-0098      VE3TCP      <gwoods () acm org>      <robohack!woods>
Planix, Inc. <woods () planix com>; Secrets of the Weird <woods () weird com>



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