I've JBoss domain controller setup in one server and JBoss host setup in another server.

I'm using cluster group with "full-ha" profile.Domain has one server and host has one server.

Could anyone please shed some light on the below?

1.How can I configure seamless failover to domain server instance if server instance in host is down and vice-versa?

Currently,I get "Internet Exploerer cannot display the page" if I hit the url.If I rehit the url,it automatically goes to domain server instance and I get the results.

2. Can I achieve seamless failover (for server instances) if I configure two hosts,each in two different servers and one domain controlling the hosts?

3.Do  need to use httpd/apache mod etc., to configure seamless failover.I'm not using any of these.Please advice.Thanks in advance