How to stop DHCP on a CSN

This short article explains how to easily disable DHCP on a CSN. This may be useful when transitioning from a CSN deployment to an SCS deployment while allowing both system to co-exist on the same private network. This would normally be problematic as both system would intercept DHCP requests in the PXE boot process.

 Instructions

Steps below are provided depending on the version of CentOS/RHEL. For 6.X versions, service is used, whereas 7.X systemctl is used.

1. SSH as root user to the CSN

2. Edit /etc/monit.conf and comment out the include line 246 so that it looks like this:

   #include /etc/monit.d/*

3. Restart monit

   service monit restart
   systemctl restart monit

4. Shut off DHCP:

   service dhcpd stop
   systemctl stop dhcpd

5. Verify DHCP is no longer running. Wait about a minute just to make sure that monit is not bringing DHCP back up.

   service dhcpd status
   systemctl stop dhcpd

6. Revert changes if/when necessary.

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