14.1. Server socket binding

14.1.1. Using “netstat” for server socket binding check

It's always interesting which server sockets are currently active on a node. Using “netstat” is a short way to get such information:

Used options: -nlptu

Example:

# netstat -nlptu
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address           Foreign Address         State      
 PID/Program name
tcp        0      0 0.0.0.0:32768           0.0.0.0:*               LISTEN     
 1258/rpc.statd
tcp        0      0 0.0.0.0:32769           0.0.0.0:*               LISTEN     
 1502/rpc.mountd
tcp        0      0 0.0.0.0:515             0.0.0.0:*               LISTEN     
 22433/lpd Waiting
tcp        0      0 1.2.3.1:139             0.0.0.0:*               LISTEN     
 1746/smbd
tcp        0      0 0.0.0.0:111             0.0.0.0:*               LISTEN     
 1230/portmap
tcp        0      0 0.0.0.0:6000            0.0.0.0:*               LISTEN     
 3551/X
tcp        0      0 1.2.3.1:8081            0.0.0.0:*               LISTEN     
 18735/junkbuster
tcp        0      0 1.2.3.1:3128            0.0.0.0:*               LISTEN     
 18822/(squid)
tcp        0      0 127.0.0.1:953           0.0.0.0:*               LISTEN     
 30734/named
tcp        0      0 ::ffff:1.2.3.1:993      :::*                    LISTEN     
 6742/xinetd-ipv6
tcp        0      0 :::13                   :::*                    LISTEN     
 6742/xinetd-ipv6
tcp        0      0 ::ffff:1.2.3.1:143      :::*                    LISTEN     
 6742/xinetd-ipv6
tcp        0      0 :::53                   :::*                    LISTEN     
 30734/named
tcp        0      0 :::22                   :::*                    LISTEN     
 1410/sshd
tcp        0      0 :::6010                 :::*                    LISTEN     
 13237/sshd
udp        0      0 0.0.0.0:32768           0.0.0.0:*                          
 1258/rpc.statd
udp        0      0 0.0.0.0:2049            0.0.0.0:*                          
 -
udp        0      0 0.0.0.0:32770           0.0.0.0:*                          
 1502/rpc.mountd
udp        0      0 0.0.0.0:32771           0.0.0.0:*                          
 -
udp        0      0 1.2.3.1:137             0.0.0.0:*                          
 1751/nmbd
udp        0      0 0.0.0.0:137             0.0.0.0:*                          
 1751/nmbd
udp        0      0 1.2.3.1:138             0.0.0.0:*                          
 1751/nmbd
udp        0      0 0.0.0.0:138             0.0.0.0:*                          
 1751/nmbd
udp        0      0 0.0.0.0:33044           0.0.0.0:*                          
 30734/named
udp        0      0 1.2.3.1:53              0.0.0.0:*                          
 30734/named
udp        0      0 127.0.0.1:53            0.0.0.0:*                          
 30734/named
udp        0      0 0.0.0.0:67              0.0.0.0:*                          
 1530/dhcpd
udp        0      0 0.0.0.0:67              0.0.0.0:*                          
 1530/dhcpd
udp        0      0 0.0.0.0:32858           0.0.0.0:*                          
 18822/(squid)
udp        0      0 0.0.0.0:4827            0.0.0.0:*                          
 18822/(squid)
udp        0      0 0.0.0.0:111             0.0.0.0:*                          
 1230/portmap
udp        0      0 :::53                   :::*                               
 30734/named