Recently I wanted to load balance a TCP service i.e. not http, in the past I’ve used ultramonkey but there doesn’t seem to be any maintained Redhat/Centos packages.
After some googling I found that haproxy can balance non-http services but examples of non-http configurations are few and far between, this blog post lead me to my solution, so after the jump I have a haproxy.cfg which will load balance smtp round-robin style across 4 servers, you also get a webstats interface listening on http://IP:8080/haproxy?stats (username = me, password = password).
By changing the port numbers from 25 (SMTP) you can effectively load balance any TCP app