The ifconfig and netstat utilities has been marked as deprecated in the man pages for CentOS 5 and 6 for nearly a decade. Redhat made the decision to no longer install the net-utils package by default in CentOS 7. The replacement utilities are ss and ip. If you really need ifconfig and netstat back then you can yum install net-utils. Source: CentOS Wiki FAQ
Below is the Man page for the SS command
NAME
ss – another utility to investigate sockets
SYNOPSIS
ss [options] [ FILTER ]
DESCRIPTION
ss is used to dump socket statistics. It allows showing information similar to netstat. It can display more TCP and state informations than other tools.
OPTIONS
When no option is used ss displays a list of open non-listening TCP sockets that have established connection.
-h, –help
Show summary of options.
-V, –version
Output version information.
-n, –numeric
Do not try to resolve service names.
-r, –resolve
Try to resolve numeric address/ports.
-a, –all
Display both listening and non-listening (for TCP this means established connections) sockets.
-l, –listening
Display only listening sockets (these are omitted by default).
-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
Print summary statistics. This option does not parse socket lists obtaining summary from various sources. It is useful when amount of sockets is so huge that parsing /proc/net/tcp is painful.
-b, –bpf
Show socket BPF filters (only administrators are allowed to get these information).
-4, –ipv4
Display only IP version 4 sockets (alias for -f inet).
-6, –ipv6
Display only IP version 6 sockets (alias for -f inet6).
-0, –packet
Display PACKET sockets (alias for -f link).
-t, –tcp
Display TCP sockets.
-u, –udp
Display UDP sockets.
-d, –dccp
Display DCCP sockets.
-w, –raw
Display RAW sockets.
-x, –unix
Display Unix domain sockets (alias for -f unix).
-f FAMILY, –family=FAMILY
Display sockets of type FAMILY. Currently the following families are supported: unix, inet, inet6, link, netlink.
-A QUERY, –query=QUERY, –socket=QUERY
List of socket tables to dump, separated by commas. The following identifiers are understood: all, inet, tcp, udp, raw, unix, packet, netlink, unix_dgram, unix_stream, packet_raw,
packet_dgram.
-D FILE, –diag=FILE
Do not display anything, just dump raw information about TCP sockets to FILE after applying filters. If FILE is – stdout is used.
-F FILE, –filter=FILE
Read filter information from FILE. Each line of FILE is interpreted like single command line option. If FILE is – stdin is used.
FILTER := [ state TCP-STATE ] [ EXPRESSION ]
Please take a look at the official documentation (Debian package iproute-doc) for details regarding filters.
USAGE EXAMPLES
ss -t -a
Display all TCP sockets.
ss -u -a
Display all UDP sockets.
ss -o state established ‘( dport = :ssh or sport = :ssh )’
Display all established ssh connections.
ss -x src /tmp/.X11-unix/*
Find all local processes connected to X server.
ss -o state fin-wait-1 ‘( sport = :http or sport = :https )’ dst 193.233.7/24
List all the tcp sockets in state FIN-WAIT-1 for our apache to network 193.233.7/24 and look at their timers.
SEE ALSO
man ip , /usr/share/doc/iproute-doc-3.10.0/ss.ps (package iproute-doc)
AUTHOR
ss was written by Alexey Kuznetosv,
This manual page was written by Michael Prokop for the Debian project (but may be used by others).