$ ip netns exec ns2 ssh 1.1.1.1
 $ ip -f inet addr show
 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
 3: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
    inet 192.168.1.123/24 scope global eth1
       valid_lft forever preferred_lft forever
 4: veth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
    inet 1.1.1.1/10 scope global veth1
       valid_lft forever preferred_lft forever

 $ ss -etn
 State  Recv-Q Send-Q  Local Address:Port  Peer Address:Port
 ESTAB  0      0             1.1.1.1:22         1.1.1.2:40412   timer:(keepalive,109min,0) ino:34868 sk:ffff880036f8b4c0 <->