Mail not arriving in user's mailbox?

[nothsa]

One of my users is complaining that they're not getting mail from some of their clients. So far they haven't received mail from 3 of the clients - each client is on a different domain name, two of them at the same IP. My user can send mail to their clients, but doesn't receive any back. I have checked the fillowing log files, but find no record of any mail from the domains or IPs in question:

/var/log/exim_mainlog
/var/log/exim_rejectlog
/var/log/exim_paniclog
/var/log/maillog

and I have checked the following blacklist files for their IPs

/etc/exim_deny
/etc/apf/deny_hosts.rules

They're not listed in there either. I have sent mail to my user via GMail (with and without attachments) and it all gets there. My user's clients are now sending the e-mails to my user's hotmail account. Is there anything else that I should be checking? I'm at a loss as to why it wouldn't even show up in the logs

[chirpy]

If it doesn't show up in your exim logs, it's not even touching your server. The most likely reason for that would be a DNS problem.

[krava]

Such issue may cause various problems with DNS. I advise you to check the DNS zone of the client's domain using DNSREPORT

http://dnsreport.com

[nothsa]

chirpy: That's what I thought, but I just wanted to be sure. Thanks

krava: Thanks for the link. I received a few warnings and am in the process of fixing them.

[Spiral]

The fact that it is not in your mail logs at all would make me think that the problem is actually on the sender's side and not on your side!

Perhaps whoever is sending your client email should be checking their own server.

The one place I would also check though on your end just to make sure is the "/etc/localdomains" file. Your client's domain name should be in that file. If it is not there then your client won't receive any mail at all.

[chirpy]

If there are no log entries in the exim_mainlog then having the domain in localdomains or not would make no difference at all as a missing entry would still log.