Unable to receive mail from cpanel.net

[webignition]

I contacted cPanel support a few days ago and never received any reply and so decided to investigate.

When checking the mail logs:

cat /var/log/exim_mainlog | grep cpanel.net

I see:

2006-05-07 10:02:14 H=(bits.cpanel.net) [69.90.250.55]
  sender verify defer for <support@bits.cpanel.net>: could not connect to
  bits.cpanel.net [69.90.250.55]: No route to host

2006-05-07 10:02:14 H=(bits.cpanel.net) [69.90.250.55]
  F=<support@bits.cpanel.net> temporarily rejected RCPT <myself@example.com>:
  Could not complete sender verify callout

(That's not the exact log entry - I've added line returns to make it more readable)

The same type of error is repeated a few times, once for each time bits.cpanel.net tried to send an email (I assume).

I can successfully ping bits.cpanel.net from both my PC and the server and can perform a traceroute successfully from both locations.

The command dig bits.cpanel.net@ns1.example.com also repsonds correctly.

I'm curious if anyone else has experienced such issues recently?

The issue about which I previously contacted cPanel support didn't matter too much and, nice as they are, someone logged in as root and fixed the issue.

However I now wish to ask cPanel support another question and would actually like to be able to receive a reply! I'll give it a shot and see what happens.

Comments anyone?

[webignition]

Well, I just tried contacting cPanel support and am again seeing the same type of errors in /var/log/exim_mainlog.

Admittedly, I could simply uncheck:

[x] Verify the existance of email senders.
[x] Use callouts to verify the existance of email senders.

from within the Exim config editor, however I'd prefer to leave these checked if at all possible. There never seemed to be a problem with them being checked before!

I could contact cPanel support about this issue (from a different email address) but for the moment I'd like to find out whether I'm the only one with this issue.

[webignition]

Actually it looks like this issue only exists when "Use callouts to verify the existance of email senders" is selected in the Exim config editor in WHM.

With:

2006-05-11 22:28:30 H=(bits.cpanel.net) [69.90.250.55]
  sender verify defer for <support@bits.cpanel.net>: could not connect to
  bits.cpanel.net [69.90.250.55]: No route to host

2006-05-11 22:28:30 H=(bits.cpanel.net) [69.90.250.55]
  F=<support@bits.cpanel.net> temporarily rejected RCPT <myself@example.com>:
  Could not complete sender verify callout

Without:

2006-05-11 22:29:11 1FeIid-0001OJ-4b <= support@bits.cpanel.net
  H=(bits.cpanel.net) [69.90.250.55] P=esmtps X=TLSv1:AES256-SHA:256 S=1019
  id=E1FeIiW-0006Vw-6h@bits.cpanel.net

cPanel support are looking into it, however in the meantime I was wondering if anyone had any suggestions?

cPanel suggested it may be related to my using MailScanner. I've asked for further details about this.

[AndyReed]

Actually it looks like this issue only exists when "Use callouts to verify the existance of email senders" is selected in the Exim config editor in WHM.

Configuring Exim with Callouts can be real pain. Just in case, you can learn more about callouts at: http://www.exim.org/exim-html-4.50/d.../spec_toc.html
Find chapter 39 >> 39.31 - 39.33.

[webignition]

Thanks Andy.

Would you then recommend against selecting "Use callouts to verify the existance of email senders" in WHM?

[AndyReed]

Would you then recommend against selecting "Use callouts to verify the existance of email senders" in WHM?

As you may know, there are two preventative SPAM measures you can enable in the WHM:

WHM > Exim Configuration Editor > Verify the existance of email senders.
WHM > Exim Configuration Editor > Use callouts to verify the existance of email senders.

With these two options on/activated, exim checks that a server that attempts to relay email to your server can actually receive email in reply. Now, these options are part of the RFC requirements of an SMTP outgoing server. if a server is unable to do that will likely to be a spammer. You can implement more RBLs/ACLs in your exim.conf to fight back spam and verify the existance of a client. This is just in case Callouts is giving you a hard time and not behaving. Hope this helps!

[chirpy]

Remember that if callouts fail, then it's not a problem with your configuration, but the senders because they're not accepting email to an address that they're sending to.

I'd suggest letting billing@cpanel.net know that they seem to have their mail server incorrectly setup for that email address and reference this thread.

[webignition]

Remember that if callouts fail, then it's not a problem with your configuration, but the senders because they're not accepting email to an address that they're sending to.

I'd suggest letting billing@cpanel.net know that they seem to have their mail server incorrectly setup for that email address and reference this thread.

Well, that's what I thought was the case.

cPanel support responded to my request by saying that it appeared to be a temporary DNS issue which has now passed. However all that was actually done was for the support agent to uncheck "Use callouts to verify the existance of email senders".

Since cPanel support suggested, albeit vaguely, that my using MailScanner might be related prompted me to check out the possibility.

I'll drop billing@cpanel.net a line and see what they say.

[chirpy]

MailScanner would have nothing whatsoever to do with it - it's so frustrating when they trip that out when all MailScanner really does to exim is related entirely to mail queuing and tranferring email between queues, it has nothing to do with the relay configuration of exim itself. Anyway, having DNS problems definitely would cause a sender callout problem, but only if this is incorrect:

bits.cpanel.net [69.90.250.55]: No route to host

The callout suggests that either:

bits.cpanel.net is incorrectly resolving to 69.90.250.55

If it should be resolving to 69.90.250.55, then it could be that email isn't running on that server

If it is running on that server, it suggests that that servers MTA won't receve email to support@bits.cpanel.net which is a problem