I've been making the upgrade to Mountain Lion server after getting one of the new shiny Mac Mini computers and ran across a couple of oddities to share:
When working on setting up the Mountain Lion VPN Service, I ran across a curious problem: I could connect fine with another OS X machine but not with iOS. The iOS device failed with the error:
os x server vpn authentication failed
If you see this error, check to see whether your shared secret has a double quote (") symbol in it. I know it sounds strange but removing that symbol makes iOS VPN usage work straight away. Odd, huh?
By default, the ssh daemon on OS X Server looks for your public key in
.ssh/authorized_keys
not
.ssh/authorized_keys2
So there you go - a couple of little irritations gone away.