ssh takes exactly 1 minute 20 seconds or 80 seconds

When I tried to use ssh to log in on another computer using ssh user@192.168.0.1.

I have to wait exactly 1 minute 20 seconds, 80 seconds, for being prompted input of password. I have accepted this long delay for months(quite patient?). I don’t have same problem when I log in to bluehost server. Also no problem from OS X.

Now, I finally know the cause. I didn’t add the remote host into /etc/hosts. In other words, client-side can’t resolve 192.168.0.1. Normally, I have such name servers in /etc/resolve.conf:

; generated by /sbin/dhclient-script
nameserver 168.95.192.1
nameserver 168.95.1.1

Which are from dhcp server, and these two name servers belong to my ISP. When I commented them out, the delay didn’t exist anymore.

When I run ssh -v user@192.168.0.1 results