In case you are looking for alternate of netstat command, here is called ss command.
By default ss command is shipped with package called iproute (Advanced IP routing and network device configuration tools)
Introduction of ss
ss command is another utility to investigate sockets. It is used to dump socket statistics. It allows showing information similar to netstat. It can display more TCP and state informations than other tools. It is considered as alternate of netstat command also.
Check ss version
Use the -V argument with ss command. It will show the version information
# ss -V
ss utility, iproute2-ss130716
Examples with ss command utility
Example 1. Display only listening sockets . Use argument -l
# ss -l
Example 2. Display all listening and non listening sockets . Use argument -a
# ss -a
Example 3. Display TCP sockets. Use argument -t or –tcp. Try with -l argument, it will print all listening TCP sockets.
ss -t
Sample:
[root@nix ~]# ss -t State Recv-Q Send-Q Local Address:Port Peer Address:Port ESTAB 0 0 192.168.56.101:ssh 192.168.56.1:38153 [root@nix ~]# [root@nix ~]# ss -tl State Recv-Q Send-Q Local Address:Port Peer Address:Port LISTEN 0 100 127.0.0.1:smtp *:* LISTEN 0 128 *:ssh *:* LISTEN 0 100 ::1:smtp :::* LISTEN 0 128 :::ssh :::* [root@nix ~]#
Example 4. Display UDP sockets. Use the argument -u or –udp . Try with -l argument
ss -u
Sample:
[root@nix ~]# ss -u State Recv-Q Send-Q Local Address:Port Peer Address:Port [root@nix ~]# [root@nix ~]# ss -ul State Recv-Q Send-Q Local Address:Port Peer Address:Port UNCONN 0 0 *:43923 *:* UNCONN 0 0 *:39372 *:* UNCONN 0 0 *:bootpc *:* UNCONN 0 0 *:bootpc *:* UNCONN 0 0 *:mdns *:* UNCONN 0 0 *:28977 *:* UNCONN 0 0 :::39372 :::* UNCONN 0 0 :::53064 :::* [root@nix ~]#
Example 5. Show process using socket.Use argument -p or –processes. Try with other arguments
ss -p
Sample:
[root@nix ~]# ss -ltp
State Recv-Q Send-Q Local Address:Port Peer Address:Port
LISTEN 0 100 127.0.0.1:smtp *:* users:(("master",1785,13))
LISTEN 0 128 *:ssh *:* users:(("sshd",1036,3))
LISTEN 0 100 ::1:smtp :::* users:(("master",1785,14))
LISTEN 0 128 :::ssh :::* users:(("sshd",1036,4))
[root@nix ~]#
Example 6. Show socket memory usage. Use argument -m or –memory
ss -m
Sample:
[root@nix ~]# ss -mta State Recv-Q Send-Q Local Address:Port Peer Address:Port LISTEN 0 100 127.0.0.1:smtp *:* skmem:(r0,rb87380,t0,tb16384,f0,w0,o0,bl0) LISTEN 0 128 *:ssh *:* skmem:(r0,rb87380,t0,tb16384,f0,w0,o0,bl0) ESTAB 0 0 192.168.56.101:ssh 192.168.56.1:38153 skmem:(r0,rb87380,t0,tb23080,f4096,w0,o0,bl0) LISTEN 0 100 ::1:smtp :::* skmem:(r0,rb87380,t0,tb16384,f0,w0,o0,bl0) LISTEN 0 128 :::ssh :::* skmem:(r0,rb87380,t0,tb16384,f0,w0,o0,bl0) [root@nix ~]#
The manual of ss utility is very helpful. To explore, use the command man ss for man pages. Or you use the command ss --help for getting help.
Reference of ss -help command
[root@nix ~]# ss -help
Usage: ss [ OPTIONS ]
ss [ OPTIONS ] [ FILTER ]
-h, --help this message
-V, --version output version information
-n, --numeric don't resolve service names
-r, --resolve resolve host names
-a, --all display all sockets
-l, --listening display listening sockets
-o, --options show timer information
-e, --extended show detailed socket information
-m, --memory show socket memory usage
-p, --processes show process using socket
-i, --info show internal TCP information
-s, --summary show socket usage summary
-b, --bpf show bpf filter socket information
-4, --ipv4 display only IP version 4 sockets
-6, --ipv6 display only IP version 6 sockets
-0, --packet display PACKET sockets
-t, --tcp display only TCP sockets
-u, --udp display only UDP sockets
-d, --dccp display only DCCP sockets
-w, --raw display only RAW sockets
-x, --unix display only Unix domain sockets
-f, --family=FAMILY display sockets of type FAMILY
-A, --query=QUERY, --socket=QUERY
QUERY := {all|inet|tcp|udp|raw|unix|packet|netlink}[,QUERY]
-D, --diag=FILE Dump raw information about TCP sockets to FILE
-F, --filter=FILE read filter information from FILE
FILTER := [ state TCP-STATE ] [ EXPRESSION ]
[root@nix ~]#