当我尝试从我的 MacBook Air (10.6) 登录远程 linux (ubuntu) 机器时，每次在我获得密码之前都会延迟大约 4-5 秒。Verbose 产生以下结果：
:~ ssh -v username@IPADDRESS
OpenSSH_5.2p1, OpenSSL 0.9.8r 8 Feb 2011
debug1: Reading configuration data /etc/ssh_config
debug1: Applying options for *
debug1: Connecting to 18.78.4.61 [18.78.4.61] port 22.
debug1: Connection established.
debug1: identity file /Users/Fabrice/.ssh/identity type -1
debug1: identity file /Users/Fabrice/.ssh/id_rsa type -1
debug1: identity file /Users/Fabrice/.ssh/id_dsa type -1
debug1: Remote protocol version 2.0, remote software version OpenSSH_5.8p1 Debian-1ubuntu3
debug1: match: OpenSSH_5.8p1 Debian-1ubuntu3 pat OpenSSH*
debug1: Enabling compatibility mode for …