cmcheckconf coredumps when "gathering network configuration"
this is because one of the standby lan interfaces on one of the nodes has been plumbed (ifconfig plumb) or is assigned an IP of 0.0.0.0 in netconf. unplumb the interface (see ifconfig), or remove it from netconf before running cmcheckconf or cmapplyconf.
Error: IP netmasks don't match, interface lan0 on node0
Error: IP netmasks don't match, interface lan0 on node1
but if your netmasks do match properly and currently in netconf, then the cluster binary file needs to be deleted and recreated from the ascii file.