I have done a fair amount of searching and haven't been able to find resolution to my problem. I am running 5.10 and have enabled "redirect" to https so that I can make webmail available externally to my 3 users. The LAN side works great and speedy every time to "problem with this sites security certificate" dialog in IE7. However, when I try to access https://mail.example.com from the internet, sometimes my users go immediately to the same certificate page and sometimes they timeout. The server that zimbra is running on is a dual-homed fanless VIA box with 1GB ram (roughly 100K available with everything running) and 1Ghz cpu that doesn't seem to be cpu bound in all the tests I have run while using top. RHEL 5.2 is installed and the firewall (SEL and iptables) is turned off. I watch connection attempts using tcpdump and see 3 https packets come in before the browser gets a timeout and 8 or 9 when successful. Right after I restart zimbra and sometimes right after I connect through the Lan port on a separate machine I get an almost instanteous connection to zimbra from the internet.
I downloaded the open source version, I do not have a trial license, I am hosting several different domains, I am the root authority for DNS on DMZ servers and have an edge network LAN dns machine that knows mail.domain.local (zimbra server) but not mail.example.com. I just put mail.example.com in my hosts file pointed to 127 and the dmz port address (192.168..) and that appears to be helping but this is the way it has been; it will work several times in a row I close the browser and come back to it an hour later and then get timeouts. After reading the posts about split DNS I thought I might try the simple approach of using the hosts file since my machine is pretty limited on resources.
Why is the internet side so sporadic in working instantaneously or timing out all within the amount of time of 5 minutes doing constant trials from the internet. I thought it might be a ethernet cable problem but is not. Is it a license key issue or a DNS issue or ... I completely don't get why it works sometimes and not others (when the machine is taxed and when it is idle). Any ideas to help stabilize would be appreciated.