Networking - Novell LINUX ENTERPRISE SERVER 10 SP2 - INSTALLATION AND ADMINISTRATION Installation Manual

17.4 Networking

17.4.1 Show the Network Status: netstat
netstat shows network connections, routing tables (-r), interfaces (-i), masquerade
connections (-M), multicast memberships (-g), and statistics (-s).
tux@mercury:~> netstat -r
Kernel IP routing table
Destination Gateway
192.168.2.0 *
link-local *
loopback *
default 192.168.2.254
tux@mercury:~> netstat -i
Kernel Interface table
Iface MTU Met RX-OK RX-ERR RX-DRP RX-OVR
eth0 1500 0 1624507 129056
lo 16436 0 23728
When displaying network connections or statistics, you can specify the socket type to
display: TCP (-t), UDP (-u), or raw (-r). The -p option shows the PID and name
of the program to which each socket belongs.
The following example lists all TCP connections and the programs using these connec-
tions.
mercury:~ # netstat -t -p
Active Internet connections (w/o servers)
Proto Recv-Q Send-Q Local Address
tcp 0 0 mercury:33513
tcp 0 352 mercury:ssh
19422/s
tcp 0 0 localhost:ssh
In the following, statistics for the TCP protocol are displayed:
tux@mercury:~> netstat -s -t
Tcp:
2427 active connections openings
2374 passive connection openings
0 failed connection attempts
0 connection resets received
1 connections established
27476 segments received
Genmask Flags
255.255.254.0 U
255.255.0.0 U
255.0.0.0 U
0.0.0.0 UG
TX-OK TX-ERR TX-DRP TX-OVR Flg
0 0 7055
0 0 0 23728
Foreign Address
www.novell.com:www-http ESTABLISHED 6862/fi
mercury2.:trc-netpoll
localhost:17828
MSS Window irtt Iface
0 0 0 eth0
0 0 0 eth0
0 0 0 lo
0 0 0 eth0
0 0 0 BMNRU
0 0 0 LRU
State PID/Pro
ESTABLISHED
ESTABLISHED -
System Monitoring Utilities 335