When using Corosync with two rings via multi-cast addresses 220.127.116.11 (Port 5405) & 18.104.22.168 (Port 5406) what iptables rules are required to allow two nodes to communicate optimally without giving any undue access and making the rules too lenient?
I current have:
iptables -A INPUT -p udp -m multiport --dports 5404,5405,5406 -j ACCEPT
Will that allow all the communication a Corosync/Pacemaker setup requires for both rings?
I have heard arguments that something like:
iptables -I INPUT 1 -m pkttype --pkt-type multicast -j ACCEPT
is required. However I cannot seem to replicate a situation where this assists if the first rule I listed above is already in place.
The Red Hat documentation would seem to support the first approach. There is some IBM documentation espousing the second but is it just a case of a rule that is far too lenient when the first would do the job equally well whilst leaving no unnecessary ports open?
I'm leaning more towards the first rule being sufficient but wanted to get some more opinions on the matter.