Forgive me in advance for my lack of knowledge on this issue, but my webserver is a CentOS machine that is primarily unmanaged. My work (web-related) through SSH is limited. However, I did know a command 'sendmail -bpc' that from my understanding will show the active mail queue. Right now it's slowly rising, but sits at around 8500 - which in my mind can't be good... Are there any troubleshooting documents/manuals or helpful sites to see what those 8500 are and if there's some better way to address. Any direct suggestions or tips as far as commands in seeing what those are would be helpful as well.
My biggest concern of course is memory, and that there might be a leak or some robot/spambot taking advantage of a vulnerability.