Re: [exim] Bogus HELOs

* Adam D. Barratt wrote (05/20/05 12:30):
> On Friday, May 20, 2005 11:41 AM, Chris Lear <chris.lear@???>
> wrote:
>
>> * Mark Smith wrote (05/20/05 10:58):
>>> Are there any *valid* reasons for a mailserver's HELO greeting not
>>> matching the hostname obtained from rDNS?
>>
>> I think so. In a virtual server environment. Say one server has 10 DNS
>> records resolving to 1 IP address. Only one name will be returned by
>> rDNS,
>
> Not necessarily. There's no reason why there can't be 10 PTR RRs for that
> IP. A number of broken pieces of software assume there will only ever be
> one, but it's perfectly legal.

You're right of course. What I said ("Only one name *will*...") is
overspecific.

But if I fix it and say "It's possible that only one name is..." I still
think it constitutes a valid reason for a HELO not matching rDNS. I
mean, I think it's valid (for some meanings of valid) to only have one
rDNS record for a given IP address, and use any of the hostnames in the
HELO greeting.

--
Chris