Re: DNS goofups galore...

James Antill (
20 Feb 2001 18:45:21 -0500

"Henning P. Schmiedehausen" <> writes:

> (James Antill) writes:
> >"Henning P. Schmiedehausen" <> writes:
> >> % telnet smtp
> >> 220 ESMTP ready
> >> ^^^^^^^^^^^^
> >>
> >> This kills loop detection. Yes, it is done this way =%-) and it breaks
> >> if done wrong.
> > This is humour, yeh ?
> No.

This was a comment on the "loop detection" claim.

[snip ... domain example]

> No. This is a misconfiguration. Yes, RFC821 is a bit rusty but as far
> as I know, nothing has superseded it yet. And Section 3.7 states
> clearly:
> Whenever domain names are used in SMTP only the official names are
> used, the use of nicknames or aliases is not allowed.

_In_ SMTP, that doesn't say anything about MX records to me and even
if it does it's very old and needs to change.

> And the 220 Message is defined as
> 220 <domain>

So... you should have the reverse for the ip address after the
220. Which most people do (but not all, mainly due to there not being
enough ips).

[snip CNAME lesson]

The question was, why can't you use CNAMEs. You said 'because of loop
detection'. I said 'But that doesn't work anyway, because you can have
to names pointing at one machine without a CNAME record ... and that
needs to, and currently does, work'.

> Dipl.-Inf. (Univ.) Henning P. Schmiedehausen -- Geschaeftsfuehrer
> INTERMETA - Gesellschaft fuer Mehrwertdienste mbH

Let me put it this way... IN MX 50 IN MX 10 IN MX 50 IN MX 10 IN A IN A IN PTR IN PTR

# James Antill --
* ^From: .*james@and\.org
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to
More majordomo info at
Please read the FAQ at