Users complain of missing emails
For weeks I have been getting complaints from my clients that detect there emails do not arrive directly lost and not reach their mailboxes and send it receives no mail, no error code First I thought of the user who sent the mail had made a mistake but when he sent a copy to another external mail coming to this client and no, I begin to suspect a serious server problem.
The question is where to start looking not ??
I have System
CentOS Linux 5.11
Webmin version 1.710
Virtualmin version 4.11 Pro Theme version 8.7
Kernel and CPU Linux 2.6.18-398.el5 on x86_64
CPU load averages 0.31 (1 min) [CPU load (1 min)] 0.37 (5 mins) [CPU load (5 mins)] 0.45 (15 mins) [CPU load (15 mins)]