網路

顯示網路狀態:netstat

netstat 顯示網路連線、路由表 (-r)、介面 (-i)、偽裝連接 (-M)、多重廣播成員 (-g) 以及統計資料 (-s)。

tux@mercury:~> netstat -r
Kernel IP routing table
Destination     Gateway         Genmask        Flags  MSS Window  irtt Iface
192.168.2.0     *               255.255.254.0  U        0 0          0 eth0
link-local      *               255.255.0.0    U        0 0          0 eth0
loopback        *               255.0.0.0      U        0 0          0 lo
default         192.168.2.254   0.0.0.0        UG       0 0          0 eth0
tux@mercury:~> netstat -i
Kernel Interface table
Iface   MTU Met   RX-OK RX-ERR RX-DRP RX-OVR  TX-OK TX-ERR TX-DRP TX-OVR Flg
eth0   1500   0 1624507 129056      0      0   7055      0      0      0 BMNRU
lo    16436   0   23728      0      0      0  23728      0      0      0 LRU

顯示網路連線或數據時,您可指定要顯示的插槽類型:TCP (-t)、UDP (-u)netstat,或 raw (-r)。-p 選項顯示 PID 和每個插槽所屬的程式名稱。

下例列出所有 TCP 連接和使用這些連接的程式。

mercury:~ # netstat -t -p
Active Internet connections (w/o servers)
Proto Recv-Q Send-Q Local Address  Foreign Address       State       PID/Pro

tcp      0      0 mercury:33513    www.novell.com:www-http ESTABLISHED 6862/fi
tcp      0    352 mercury:ssh      mercury2.:trc-netpoll     ESTABLISHED 19422/s
tcp      0      0 localhost:ssh  localhost:17828         ESTABLISHED -

以下會顯示 TCP 通訊協定的統計資料:

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
    26786 segments send out
    54 segments retransmited
    0 bad segments received.
    6 resets sent
[...]
    TCPAbortOnLinger: 0
    TCPAbortFailed: 0
    TCPMemoryPressures: 0