I am running 5.0.18 on Redhat 5.2 and my system is sending and receiving email fine. I am using the embedded httpd / jetty and recently upgraded from 5.0.10. What I have noticed and have not been able to solve is that http access from outside the firewall from public ip addresses doesn't work sometimes when trying to use the http client. The mail server is dual homed with a dmz address (192.) and a LAN address (10.) and it does not have apache installed, selinux is off and the firewall is off.
Everytime I use the http client from a machine (other than mail server) in the dmz or the LAN it works. It works everytime using localhost on the mail server as well. I have looked at logs, used tcpdump, and netstat and from what I can see the only addresses that always work to get the http client are the trusted networks (MTATrustedNetwork). My hosts file has 2 lines, one with the 127 address and one with the 192 address.
When using a browser from 68. public ip (using my cellular broadband service) it sometimes doesn't work until after there is an existing http session. When I do that, netstat shows mail.domain.local (name of my mail server) connection and then magically my 68. public ip connection then begins working again. The other time it seems to work for awhile is after I zmcontrol stop and then start. Then a few hours later not even my telnet to port 80 is allowed a connection (connection failed). I can see the 4 RECV requests come in (netstat |grep http) but they are not answered (netstat -l |grep http shows port 80 listening). It will work sometimes for 12 hours and then no joy.
Any ideas why httpd / jetty doesn't always pick up connections from public ip addresses on port 80 unless there is already an existing http connection to the machine ?