We are seeing this for some (not many) email messages. After flushing the deferred queue, they then get delivered.
'host or domain name not found. name service error for name=mail2.billionauto.com type=a: host not found, try again'
We did fix our hosts file.
I had another thread on this problem that fizzled out and died so I wanted to really focus on some more specifics and cover perhaps some new findings on our side.
A quick writeup on our problem is that our mail server, throughout the day, becomes unresponsive. Webmail and POP mail clients can't send or receive mail. Webmail actually just hangs and you cannot even get to the login screen while this is taking place.
We upgraded to version 7 in hopes of remedying this problem without any luck. I would like to post this from our Zimbra logs and then also include that while this is happening, our Zimbra server still makes connections to our mail proxy and accepts mail; which it does not have to authenticate with.
This happens for all users during our outages. Once these errors stop, email access is working again. I appreciate any help that you can send my way. Thanks.
Feb 14 08:28:01 xyz saslauthd: authentication against url 'https://XYZ.com:7071/service/admin/soap/' caused error 'curl_easy_perform: error(28): SSL connection timeout'
Feb 14 08:28:01 xyz saslauthd: url 'https://XYZ.com:7071/service/admin/soap/' will not be used for (at least) 600 seconds
Feb 14 08:28:01 xyz saslauthd: Authentication cycle re-elected url https://xyz.com:7071/service/admin/soap/, giving up ...
Feb 14 08:28:01 xyz saslauthd: auth_zimbra: xyzuser auth failed: curl_easy_perform: error(28): SSL connection timeout
Feb 14 08:28:01 xyz saslauthd: do_auth : auth failure: [user=xyzuser] [service=smtp] [realm=] [mech=zimbra] [reason=Unknown]
Feb 14 08:28:02 xyz postfix/smtpd: warning: unknown[10.xxx.xxx.xxx]: SASL LOGIN authentication failed: authentication failure
No, we haven't installed and configured DNS on our Zimbra server. We will discuss it but our DNS server hasn't been problematic. As a workaround, can I enter the IP address in any of the config files? Like where 'https://XYZ.com:7071/service/admin/soap/' appears in our zimbra.log file, would having our server IP in there give us the same troubleshooting steps as installing DNS locally? Thanks.