How to fix slow ssh connect

reason 1 : use DNS
... another blog..

reason 2 : GSSAPIAuthentication
This is my reason

I am SERVER
vi /etc/ssh/sshd_config
# GSSAPI options
GSSAPIAuthentication no
#GSSAPIAuthentication yes

I am CLIENT
vi /etc/ssh/ssh_config
Host *
#       GSSAPIAuthentication yes
        GSSAPIAuthentication no

reference:
http://allthatlinux.com/dokuwiki/doku.php?id=ssh_%EC%A0%91%EC%86%8D%EC%8B%9C_%EC%8B%9C%EA%B0%84_%EC%A7%80%EC%97%B0_%EC%A0%91%EC%86%8D_%EC%98%A4%EB%9E%98%EA%B1%B8%EB%A6%BC_%ED%98%84%EC%83%81_%ED%95%B4%EA%B2%B0