Well, I downloaded the Zimbra Collaboration Suite 5.0 RC 1. I installed it on Fedora 7 that is running as a virtual machine. The installation was not difficult. Just follow the instructions that come with the package. I just had to change one setting in the sudo config file:

$ visudo
#Defaults requiretty

My webserver is running on another VM and I only got one internet ip address. So to connect to Zimbra Webmail running on my Zimbra server, I use my webserver as a proxy. I just configured my Webservers Apache config file something like this:

# Redirect traffic to/from webmail.mydomain.com to zimbra.lan
<VirtualHost *:80>
ServerName webmail.mydomain.com
ProxyPass / http://zimbra.lan/
ProxyPassReverse / http://zimbra.lan/
</VirtualHost>

Well, when I finished the installation I tried the webinterface and I got enthousiastic. The admin website is pretty simple and the webmail client looks pretty impressive. The functionality is good. You can easily to share your calender, make appointments, send mail, etc. I ran into a few problems though:

• Zimbra reccomends to use 1GB of memory. Due to limited memory resources in my VMware host I started out with 512 MB of memory for the Zimbra VM. This is not enough, performance is really slow. My host is slow and the other VM's also get influenced negatively by this lack of resources. I now use 1024MB for the VM, this helps a lot! Compared to other Linux VM's (all without X_Windows), it needs a lot of memory.

• You can install a Zimbra tool, the Zimbra Toaster, on your Windows desktop that will tell you if you received new emails. I've had some problems with it like getting messages about new emails, while in fact I read the email already. And the software crashed a couple of times. But, it's still in alpha, so I it's not stable yet.

Zimbra positions itself, like Postpath, as an alternative for Microsofts Exchange server. I can't tell you if this is really an option because I am not familiar yet with MS Exchange. Zimbra supports mobile email clients, I have none so I could not test it. But in my opinion a small company can easily use the open Source edition of Zimbra.

Handy commands:

# su - zimbra
# zmcontrol status|stop|start
# zmapachectl status|stop|start
# zmmailbox
# zmmsgtrace -t <emailladdress_of_a_mailbox>
# zmmsgtrace -r <emailladdress_of_a_mailbox> -s <emailladdress_of_a_mailbox> -t 20071027
# dig r71.nl. mx +trace

# /opt/zimbra/libexec/zmsetup.pl
# /opt/zimbra/libexec/zmconfigure

Uptill now I use a daily restart of the zimbra services (crontab of zimbra user). If I don't do this the server crashes after a couple of weeks...