I am currently using High Availability Extension on SUSE Linux
Enterprise Server 11. I have two nodes running on a cluster. I have some
iptables inserted and as a result, the nodes sitting in the same cluster
could not see each other. The port and multicast address indicated in
"/etc/corosync/corosync.conf" has been added to my ip table.
I also referenced from this following URL: 'Corosync UDP ports - Open
SA Forum AIS Services mailing list - ArchiveOrange'
Corosync uses port <n> and <n-1>, which I had also added <n-1> port into