On the receiver run: tcpdump host <ip of sender> On sender run:   echo "PING" > /dev/udp/<ip of receiver>/<port #> Example: Sender $ echo "PING" > /dev/udp/192.9.20.115/6000" Receiver $ sudo tcpdump host 192.9.20.111 [sudo] password for jeverson: tcpdump: verbose output suppressed, use -v or -vv for full protocol decode listening on enp0s25, link-type EN10MB (Ethernet), capture size 65535 bytes 12:13:51.616237 IP mc-server.all-offroad.net.37052 > kate.all-offroad.net.6000: UDP, length 5 12:13:51.616314 IP kate.all-offroad.net >...

After what seemed like days of messing with permissions, SELinux was the problem. To solve the dreaded Could not stat() command file ‘/usr/local/nagios/var/rw/nagios.cmd’!” error, when trying to reschedule a test or acknowledge an alert, a simple setenforce 0 was the solution. Though, permissions do also have to be correct. chown nagios.nagcmd /usr/local/nagios/var/rw chmod g+rwx /usr/local/nagios/var/rw chmod g+s /usr/local/nagios/var/rw

The first thing I wanted to do was deal with the web server. I didn’t want apache serving any pages other than nagios. I decided to redirect everything to techmentor.com. To do this I has to allow overrides int the main conf file: <Directory “/var/www/html”>     Options Indexes FollowSymLinks    AllowOverride All    Order allow,deny    Allow from all </Directory> Then in /var/www/html I created the following .htaccess file: RewriteEngine on AddType text/cache-manifest manifest RewriteCond %{HTTP_HOST} ^backwater\.techmentor\.com$ RewriteRule ^/?$...

Amount of Memory sysctl -a | grep hw.memsize: or /usr/sbin/system_profiler SPHardwareDataType | grep Memory Amount of Swap ls -al /private/var/vm/swapfile0 | awk ‘{print $5}’ Amount of Free Swap vm_stat | awk ‘/Pages free:/ {print substr($3,1,match($3,/\./)-1)}’