Hi. > > From: Terry Smith <[EMAIL PROTECTED]> > > Date: 08 Feb 2003 18:05:40 -0500 [...] > > Final-Recipient: RFC822; <[EMAIL PROTECTED]> > > Action: failed > > Status: 5.2.0 > > Remote-MTA: dns; linux-mandrake.com > > Diagnostic-Code: smtp; 450 Client host rejected: cannot find your hostname, >[64.8.50.181] [...]
On Sat 2003-02-08 at 19:58:04 -0500, [EMAIL PROTECTED] wrote:
[...]
> When you send a message to sympa, the Mandrake list server, it tries
> to do a reverse lookup on the ip address of the smtp server sending
> the connection to match the smtp domain name against the domain name
> of the from address. I gather that this technique is to prevent a
> spam attack from happening.
Looks like that is the problem. Yes, reverse lookups are common
practice, not only by mail software. It's an easy and reasonable way
to raise the bar for abuse.
> This kind of thing happens when the mailhost you are sending through
> is a virtual server, meaning there is one numeric ip address for
> many domains.
Not completely correct. What you refer to is the fact that it can
happen that the reverse lookup results in a different name than
the domain provided originally, e.g.
$ urpmi bind-utils
$ host www.nic.de
www.nic.de has address 194.246.96.76
but
$ host 194.246.96.76
76.96.246.194.in-addr.arpa domain name pointer direct.denic.de.
76.96.246.194.in-addr.arpa domain name pointer intern.denic.de.
76.96.246.194.in-addr.arpa domain name pointer member.denic.de.
76.96.246.194.in-addr.arpa domain name pointer secure.denic.de.
76.96.246.194.in-addr.arpa domain name pointer project.denic.de.
76.96.246.194.in-addr.arpa domain name pointer transit.denic.de.
76.96.246.194.in-addr.arpa domain name pointer wwwtest.denic.de.
76.96.246.194.in-addr.arpa domain name pointer intern-old.denic.de.
76.96.246.194.in-addr.arpa domain name pointer www.denic.de.
76.96.246.194.in-addr.arpa domain name pointer jobs.denic.de.
76.96.246.194.in-addr.arpa domain name pointer test.denic.de.
76.96.246.194.in-addr.arpa domain name pointer board.denic.de.
Although they made the effort to list all the reverse lookups, they
missed www.nic.de in their list. So if the server makes a connection
as www.nic.de (which they probably don't do), the other side would end
up with a different name by the reverse lookup.
But the cited error message (cannot find your hostname, [64.8.50.181])
indicates that the reverse lookup failed completely. You can easily
check this yourself:
$ host 64.8.50.181
Host 181.50.8.64.in-addr.arpa not found: 3(NXDOMAIN)
If you look at me, I am currently online as
pD9EB55B6.dip.t-dialin.net, which resolves fine:
$ host pD9EB55B6.dip.t-dialin.net
pD9EB55B6.dip.t-dialin.net has address 217.235.85.182
$ host 217.235.85.182
182.85.235.217.in-addr.arpa domain name pointer pD9EB55B6.dip.t-dialin.net.
> In this case, sympa cannot do the reverse lookup and
> quietly rejects the message.
Well, not exactly quietly. You did get a bounce, didn't you? The
reason it takes 4-5 days to bounce is because your mail server
(@adelphia.net) handles it as temporary failure and retries for some
time before giving up (that's perfectly okay, because most times this
error will be due to some DNS problems).
> I am also a subscriber to Adelphia PowerLink and I cannot use my
> @adelphia.net address to send to the list. I must use a POP3
> account I have on my professional association.
Although I am no specialist regarding this issue, I consider it a
misconfiguration of adelphia.net DNS entries. You should probably
report the problem to [EMAIL PROTECTED] and see what they say.
> Another problem with Adelphia specifically is the way they route their mail.
> He may have been allowed by sympa to subscribe, but then the smtp server he
> was using changed because of Adelphia's load balancing, rotation or network
> problems, which sympa does not like.
Really? The mailing list should not care at all which way a mail is
routed. I did not notice any problem when my mail routing changed last
November.
> As long as he is receiving messages, it may be worthwhile to get a free portal
> address at Yahoo or Excite and send messages to the list from there.
As I said, if I am not mistaken, that is a problem with Adelphia's DNS
configuration. They should either fix the problem or be able to tell
specifically who else is the culprit. If not, then I would seriously
consider another provider, because you cannot know what else they
don't know how to handle.
> I have tried sending an e-mail to MandrakeSoft to get an explanation
> for this and no one responded, so this is what I have surmised from
> the evidence I have.
Well, they are kind of over-worked all the time and it is not a
problem they can do much about anyhow, I think.
HTH,
Benjamin.
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