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

  • From: Greg A. Woods
  • Date: Mon Jul 10 14:27:51 2000

[ On Monday, July 10, 2000 at 12:36:52 (-0400), Shawn McMahon wrote: ]
> Subject: Re: RBL-type BGP service for known rogue networks?
>
> *ANYBODY* running sendmail on a box with a dynamic IP is going to see
> this behavior, unless they play magic sed games to change their sendmail
> config every time their IP changes.  This actually would be doable in my
> case, but is hardly expectable of everybody who uses a dynamic IP.

True enough.

That's why people without real Internet connections should be using
their ISPs authorised outgoing SMTP relay host, and not pretending by
playing silly games with DNS.

> And then there are those MUAs that also act as MTAs, doing their own SMTP
> without going through an external server.  They can't all be configured
> to do what Greg proposes, and who in their right mind would want them to
> be?

Yes, they can.  And most in fact are.  And they *MUST* be actually.

If you're going to wave the RFC back in my face the least you can do is
acknowledge that you're also violating its emphasised requirements.

In degrees of violation though it's very important to understand that I
can violate the second part of that rule and I only affect my own
services.  Your violation of the first part of that rule affects
everyone your mailer might happen to contact.

> DNS will resolve "oa.eiv.com" to the exact IP of the box sending the email.

No, it won't.  A CNAME RR does not contain an IP number in as its value.

The rules are designed in such a way as to avoid having a SMTP server
waste its time chasing CNAMEs, especially when they may easily end up in
a loop and have to have even more complex code to detect and handle such
error conditions.

If you're going to play the game you could at least learn the rules so
that you know when you're in the wrong.

-- 
							Greg A. Woods

+1 416 218-0098      VE3TCP      <[email protected]>      <robohack!woods>
Planix, Inc. <[email protected]>; Secrets of the Weird <[email protected]>