[Linux/ssh] Why does the “password” prompt take forever when I SSH
It was, in fact, performing reverse DNS resolution. Based on the suggestions below and this article, I added "UseDNS no" to my sshd_config, rebooted ssh, and now the password prompt displays immediately.
When I SSH into my server I am given the standard "login as:" prompt, followed by the "user@host's password:" prompt. For whatever reason, the second one always takes a while to display. My server isn't under any load and typically executes commands quite fast.
Now, we're talking only 10 seconds or so between the time I hit Enter for the username and when the second prompt displays, but when you do this a lot it gets annoying. I suspect Ubuntu is looking up my user account, but it has < 5 accounts on the entire installation.