Snow Leopard server is a good system, however it does still suffer nasty bugs or you have to understand small gotchas to make things work as expected.
Here’s a roundup on what I found.

snow leopard

Server

Q: is that true that many tools and settings depends on DNS?

A: yes. Please configure your DNS before anything else. And preferably remember to not stop this service unless you know what are you doing.

Q: occasionally upon reboot every user, especially admins, have to reauthenticate with the server for many servers. Is that normal?

A: it shouldn’t be, but can happen. Nobody knows why, tho.

Mailman

Q: setting up a new mailing list will cause it to appear as name@machine.domain.com, I want name@domain.com, how can I do that?

A: You can’t do this from Server Admin. You have to go into mailman mailing list preferences http://yourserver/mailman/admin/mailinglistname and change the host_name directive to include only the domain.
Also you may want to lowercase real_name directive.

Q: by looking at the logs, it seems like that mailman can’t deliver external mail because the mail server refuses to relay. Also it seems that greylisting kicked in, what can I do about that?

A: open Server Admin, Mail, Settings, Relay. If you have 127.0.0.0 in Accept SMTP relays that’s not enough, try setting it at 127.0.0.1/32 and try again.

Q: when I drag users from my OD panel into a mailman mailing list, email addresses are screwed up, what can I do?

A: it seems normal. Just double click on the name and fill the proper email address, no big deal.

Mail services

Q: I keep seeing in my smtp logs that external connections are denied in some way, like the server responds that the service is not available.

A: just wait. This is an anti-spam technique called graylisting. Once the external smtp server tries to send an email again, it will be accepted and its IP inserted in a temporary table to allow following messages, until it expires.

Q: How can I add virtual domain users? I already have users in open directory, but they won’t receive email or I want them to receive email on multiple addresses.

A: open Workgroup Manager, select your user and user short name in Basic info tab add your email addresses. Beware though, read on before doing this operation.
Also remember to open Server Admin, Mail, Settings, Advanced, Hosting, and enable your domains in the second table.

Q: I added some short names to my users, however for some reason my accounts got screwed up.

A: this is a bug in Workgroup Manager in the underlying code. To properly add short names enable inspector and add them under dsAttrTypeNative.uid

VPN

Q: My L2TP over IPSec VPN stopped working for some reason. What can I do?

A: if log doesn’t tell you anything interesting this is unknown. Try using PPTP.

Q: how can I stop redirecting all the traffic from my machine to my VPN? I want only the proper traffic to be tunneled.

A: open Server Admin, VPN, Settings, Client Information, in Network Routing Definition add a new route of type Private containing the information of the remote local network.

Q: I don’t understand what kind of IP address should I give to VPN clients.

A: assign an IP range outside your DHCP one, this is important.

Web Services

Q: Apache doesn’t start. It keeps crashing

A: there are many reasons for this, but I would check out if error page and log files really exists on server, no matter if they are disabled. Web settings from Server Admin is fragile as interface, and bugged out multiple times.
Please note that also you MUST fill every field in the General tab, even if you don’t use those settings.

Q: how can I protect with username and password a web directory?

A: you want something that Server Admin calls Realm. open Web, Sites, select your site, Realms, add one clicking the plus symbol to the left and proceed adding your users.

Screen sharing

Q: when I installed the server I could connect to it with Screen Sharing tool with no problems, now I need to connect, close the program and rerun it to see my screen, what can I do?

A: currently I have found no solution to this problem.