netstat
NAME
netstat - Print network connections, routing tables, interface statis�\
tics, masquerade connections, and multicast memberships
SYNOPSIS
netstat [address_family_options] [--tcp|-t] [--udp|-u] [--raw|-w]
[--listening|-l] [--all|-a] [--numeric|-n] [--numeric-hosts]
[--numeric-ports] [--numeric-users] [--symbolic|-N]
[--extend|-e[--extend|-e]] [--timers|-o] [--program|-p] [--verbose|-v]
[--continuous|-c]
netstat {--route|-r} [address_family_options]
[--extend|-e[--extend|-e]] [--verbose|-v] [--numeric|-n]
[--numeric-hosts] [--numeric-ports] [--numeric-users] [--continuous|-c]
netstat {--interfaces|-i} [--all|-a] [--extend|-e[--extend|-e]] [--ver�\
bose|-v] [--program|-p] [--numeric|-n] [--numeric-hosts] [--numeric-
ports] [--numeric-users] [--continuous|-c]
netstat {--groups|-g} [--numeric|-n] [--numeric-hosts]
[--numeric-ports] [--numeric-users] [--continuous|-c]
netstat {--masquerade|-M} [--extend|-e] [--numeric|-n]
[--numeric-hosts] [--numeric-ports] [--numeric-users] [--continuous|-c]
netstat {--statistics|-s} [--tcp|-t] [--udp|-u] [--raw|-w]
netstat {--version|-V}
netstat {--help|-h}
address_family_options:
[-4] [-6] [--protocol={inet,unix,ipx,ax25,netrom,ddp}[,...]]
[--unix|-x] [--inet|--ip] [--ax25] [--ipx] [--netrom] [--ddp]
DESCRIPTION
Netstat prints information about the Linux networking subsystem. The
type of information printed is controlled by the first argument, as
follows:
(none)
By default, netstat displays a list of open sockets. If you don't
specify any address families, then the active sockets of all configured
address families will be printed.
--route , -r
Display the kernel routing tables. See the description in route(8) for
details. netstat -r and route -e produce the same output.
--groups , -g
Display multicast group membership information for IPv4 and IPv6.
--interfaces, -i
Display a table of all network interfaces.
--masquerade , -M
Display a list of masqueraded connections.
--statistics , -s
Display summary statistics for each protocol.
OPTIONS
--verbose , -v
Tell the user what is going on by being verbose. Especially print some
useful information about unconfigured address families.
--wide , -W
Do not truncate IP addresses by using output as wide as needed. This is
optional for now to not break existing scripts.
--numeric , -n
Show numerical addresses instead of trying to determine symbolic host,
port or user names.
--numeric-hosts
shows numerical host addresses but does not affect the resolution of
port or user names.
--numeric-ports
shows numerical port numbers but does not affect the resolution of host
or user names.
--numeric-users
shows numerical user IDs but does not affect the resolution of host or
port names.
--protocol=family , -A
Specifies the address families (perhaps better described as low level
protocols) for which connections are to be shown. family is a comma
(',') separated list of address family keywords like inet, unix, ipx,
ax25, netrom, and ddp. This has the same effect as using the --inet,
--unix (-x), --ipx, --ax25, --netrom, and --ddp options.
The address family inet includes raw, udp and tcp protocol sockets.
-c, --continuous
This will cause netstat to print the selected information every second
continuously.
-e, --extend
Display additional information. Use this option twice for maximum
detail.
-o, --timers
Include information related to networking timers.
-p, --program
Show the PID and name of the program to which each socket belongs.
-l, --listening
Show only listening sockets. (These are omitted by default.)
-a, --all
Show both listening and non-listening sockets. With the --interfaces
option, show interfaces that are not up
-F
Print routing information from the FIB. (This is the default.)
-C
Print routing information from the route cache.
详细参考man netstat
常见比较有用的：
1，netstat -r 比较容易查到路由信息
2，netstat -t/-u -p -numeric-ports -numeric-hosts 可以查到相关端口的应用情况