Hi everybody,
we are trying to pin down a problem with our mailserver. Since a few weeks every now and then we got reports form customers, that "mail isn't working". Most of the time we checked and found nothing. Then we encountered problems ourselves, i.e. I set up test accounts in my Outlook and had those check for new mails every 5 minutes. Sure enough I sometimes got error messages from Outlook in the likes of "server is not answering". But those problems always went away by themselves and we didn't find any hints in the log files. We didn't pursue this with full force, since it was only intermittent (but we should have).
Then a week ago another customer called and said, he couldn't send out mail. I checked, and I couldn't either. I restartet the primary SMTP (25, TLS optional) to no avail, then the Alternate SMTP (Port 587 with TLS requiered) and mails went through again. So we checked more thoroughly, but still couldn't find anything related in the logs (btw, how do you guys analyze the logs, do you convert them in order to make the time stamps readable?)
Today we had another call and the same thing happened again. I took some time to look a log files and checked if all services were running as they should and found nothing out of the ordinary. So I restarted the Alternate SMTP again, nothing. I restarted all other MTA services, nothing. I restarted MDA services, the firewall, still nothing. As this took too much time already, I rebootet and everything was fine again.
So, here I am asking for ideas on how to track this bugger down.
We think SSL/TLS might be a possible cause. Whenever this problem happened, I could still send out mails through the primary SMTP unencrypted. And the problems Outlook sometimes reported are also occuring when checking for new mail (i.e. IMAPs/POP3s). The mailserver did work fine for months now, might this have to do with the changes to SSL since poodle OR the upgrade to centOS 6.6?
Any ideas are very welcome, as we can't really pin this down...
Thanks in advance.
Michael
we are trying to pin down a problem with our mailserver. Since a few weeks every now and then we got reports form customers, that "mail isn't working". Most of the time we checked and found nothing. Then we encountered problems ourselves, i.e. I set up test accounts in my Outlook and had those check for new mails every 5 minutes. Sure enough I sometimes got error messages from Outlook in the likes of "server is not answering". But those problems always went away by themselves and we didn't find any hints in the log files. We didn't pursue this with full force, since it was only intermittent (but we should have).
Then a week ago another customer called and said, he couldn't send out mail. I checked, and I couldn't either. I restartet the primary SMTP (25, TLS optional) to no avail, then the Alternate SMTP (Port 587 with TLS requiered) and mails went through again. So we checked more thoroughly, but still couldn't find anything related in the logs (btw, how do you guys analyze the logs, do you convert them in order to make the time stamps readable?)
Today we had another call and the same thing happened again. I took some time to look a log files and checked if all services were running as they should and found nothing out of the ordinary. So I restarted the Alternate SMTP again, nothing. I restarted all other MTA services, nothing. I restarted MDA services, the firewall, still nothing. As this took too much time already, I rebootet and everything was fine again.
So, here I am asking for ideas on how to track this bugger down.
We think SSL/TLS might be a possible cause. Whenever this problem happened, I could still send out mails through the primary SMTP unencrypted. And the problems Outlook sometimes reported are also occuring when checking for new mail (i.e. IMAPs/POP3s). The mailserver did work fine for months now, might this have to do with the changes to SSL since poodle OR the upgrade to centOS 6.6?
Any ideas are very welcome, as we can't really pin this down...
Thanks in advance.
Michael