Netstat command displays the network related information such as network connections, routing tables, interface statistics. Following are few examples on how to use netstat command.
Display Active Internet Connections and domain sockets using netstat
# netstat –an Active Internet connections (servers and established) Proto Recv-Q Send-Q Local Address Foreign Address State tcp 0 0 0.0.0.0:5666 0.0.0.0:* LISTEN tcp 0 0 0.0.0.0:111 0.0.0.0:* LISTEN tcp 0 0 0.0.0.0:4086 0.0.0.0:* LISTEN skipped.. Active UNIX domain sockets (servers and established) Proto RefCnt Flags Type State I-Node Path unix 2 [ ACC ] STREAM LISTENING 7894 /tmp/.font-unix/fs7100 unix 2 [ ACC ] STREAM LISTENING 9662 /tmp/.gdm_socket unix 2 [ ACC ] STREAM LISTENING 10897 @/tmp/fam-root-
Display Active Connections with Process ID and Program Name
This could be very helpful to identify which program has initiated a specific network connection.
# netstat -tap Active Internet connections (servers and established) Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name tcp 0 0 *:nrpe *:* LISTEN 16277/xinetd tcp 0 0 localhost.localdomain:smtp *:* LISTEN 7263/sendmail: acce tcp 34 0 localhost.localdomain:54221 localhost.localdomain:4089 CLOSE_WAIT 29881/httpd tcp 0 3216 dev-db:ssh cpe-76-94-215-154.soca:4682 ESTABLISHED 11717/sshd: ramesh
Display Routing Table
# netstat –-route Kernel IP routing table Destination Gateway Genmask Flags MSS Window irtt Iface 192.168.1.0 * 255.255.255.0 U 0 0 0 eth0 220.127.116.11 * 255.255.0.0 U 0 0 0 eth0 default 192.168.1.1 0.0.0.0 UG 0 0 0 eth0
Display RAW network statistics
# netstat --statistics --raw Ip: 11080343 total packets received 0 forwarded 1 with unknown protocol 0 incoming packets discarded 11037744 incoming packets delivered 11199763 requests sent out Icmp: 577135 ICMP messages received 64 input ICMP message failed. ICMP input histogram: destination unreachable: 537 timeout in transit: 65 source quenches: 2 echo requests: 576476 echo replies: 12 timestamp request: 3 address mask request: 3 581558 ICMP messages sent 0 ICMP messages failed ICMP output histogram: destination unreachable: 5079 echo replies: 576476 timestamp replies: 3
Misc Netstat Commands
List of TCP connection to and from the machine.
# netstat –-tcp –-numeric
Display TCP port that the server is listening on along with the program that is listening on that particular port.
# netstat --tcp --listening –-programs
Display the routing cache
# netstat –rnC
Comments on this entry are closed.
awesome stuffs you have been providing.
How could I get the Proxy server IP for a particular application running in a server?
In UNIX environment.
Thanx n Regards
Could you please elaborate about the error message “64 input ICMP message failed.”
What does it mean, does it mean that there are some packets dropping at the host end and how to troubleshoot it.