To see if yourserver.com is an open relay, you can run through the following sequence on any box that has...
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security
Wireshark and tcpdump are extremely powerful network troubleshooting tools. Here are some command examples...
Getting SELinux working can be tough. Here are some commands I found useful.
Show the security...
After a fair amount of trial and error, I have finally discovered a way to back up files on one system...