FAQ: Why is SSH into my server so slow?!
I have run in to this a zillion times. You SSH to a Unix server, type your password, and then wait a minute or two before you get the initial shell prompt, after which everything is reasonably zippy.
The short answer is “probably, something is wrong with DNS . . . your server is trying to look up your client but it can not, so it sits there for a couple of minutes until it times out, and then it lets you in.”
Yesterday I was working with an artist who had a hosting account, and when he got in, I said:
sudo vim /etc/resolv.conf
He admitted that he had just copied the DNS configuration from his previous server. How to fix this? Well, he could check what nameservers are provided by his current hosting company . . . . or, I changed his file to read:
“What’s that, localhost?”
“It’s Google! Wherever you are, they’ll give you DNS.”