Hi I recently met with a problem when trying to set up ssh connection through the ssh key I first create a key through command ssh-keygen -t rsa -f /.ssh/pmcftp_id_rsa -P "" , two files would be created under /.ssh pmcftp_id_rsa and pmcftp_id_rsa.pub, then I insert an entry into the .pub file - from="47.154.169.129,47.154.169.128" this should restrickt that the ssh key should only work for sources of these two ips. Then I push the public key to another server under ~pmcftp/.ssh, after that, I start the ssh connection through command ssh -I pmcftp -i. ./ssh/pmcftp_id_rsa <server ip>, the ssh connection would be set up without asking for the passwd. But, when I create the ssh key on a server that has several ip address, like following: ===== ifconfig -a lo0: flags=2001000849<UP,LOOPBACK,RUNNING,MULTICAST,IPv4,VIRTUAL> mtu 8232 index 1 inet 127.0.0.1 netmask ff000000 uplink0: flags=1040863<UP,BROADCAST,NOTRAILERS,RUNNING,MULTICAST,DEPRECATED,IPv4> mtu 1500 index 2 inet 47.154.169.130 netmask ffffff00 broadcast 47.154.169.255 ether 0:0:bb:2e:74:e uplink0:1: flags=1000863<UP,BROADCAST,NOTRAILERS,RUNNING,MULTICAST,IPv4> mtu 1500 index 2 inet 47.154.169.128 netmask ffffff00 broadcast 47.154.169.255 uplink0:2: flags=1000863<UP,BROADCAST,NOTRAILERS,RUNNING,MULTICAST,IPv4> mtu 1500 index 2 inet 47.154.169.129 netmask ffffff00 broadcast 47.154.169.255 uplink1: flags=1000843<UP,BROADCAST,RUNNING,MULTICAST,IPv4> mtu 1500 index 3 inet 192.168.47.1 netmask ffffff00 broadcast 192.168.47.255 ether 0:0:bb:2e:74:d ===== And added ip 47.154.169.128 and 47.154.169.129 into the from ip list entry in the key file, then I push the ssh key to server 47.154.169.130 (which should be the same server as the source) Then when I try to start the ssh connection through command ssh -I pmcftp -i. ./ssh/pmcftp_id_rsa 47.154.169.130 , the key does not work anymore, and the log give info like this == Authentication tried for pmcftp with correct key but not from a permitted host (host=iems196-unit0, ip=47.154.169.130) == Obviously, here the from ip list does not include 47.154.169.130, and the ssh connection treate the from ip as 47.154.169.130 not other ips of this server. Then I tried another command Ssh -b 47.154.169.128 -I pmcftp -i. ./ssh/pmcftp_id_rsa 47.154.169.130 the key works well again. The -b option is binding the from ip to 57.154.169.128 and it's in the from ip list in the key file. how the ip of the from side of the ssh connection is obtained? When the from side of the ssh connection has several ips how would the ip address be determined by the to side? Any info would be highly appreciated, thanks in advance! Best regards Guang -- 徐广 13581797776