50. Linux shell commands, netstat, Traceroute

1. netstat

1) netstat [Option]

Parameter descriptions related to routing:

①-R: lists the route tables. The function is similar to the route command;

②-N: The Host Name and service name are not used. The IP address and port number are used, just like route-n.

Parameters related to the network interface:

③-A: Lists All connection statuses, including TCP, UDP, and Unix sockets;

④-T: only lists the connections of TCP packets;

⑤-U: only lists connections of UDP packets;

⑥-L: only lists the network statuses of services monitored by listen;

7.-P: names of PID and program files;

Bytes-C: it can be set to automatically update once after several seconds, for example,-C 5 updates the network status once every five seconds;

Bytes-S displays their statistical data based on each Protocol [3]

Bytes-E: Display Ethernet statistics

2) Example

Netstat-Rn

Netstat-n

Netstat-T

2. Traceroute

Traceroute [Option] IP

1) Option

①-N: host name resolution is not required. IP addresses are used only, and the speed is faster.

②-U: UDP port 33434 is used for detection. This is the preset Detection protocol;

③-I: use ICMP for detection;

④-T: TCP is used for detection. Generally, port 80 is used for testing.

⑤-W SEC: if the recipient's host does not receive an echo within a few seconds, noPass,The default value is 5 seconds.

⑥ -P port if you do not want to use the UDP and TCP presets port number, which can be changed here port .

7.-I interfaceFor exampleThere are two PPP instances. You can use-I to choose whether ppp0 or ppp1.

Bytes-G Gateway: similar to the-I parameter, but-G is followed by the gateway IP address.

2) Example

Traceroute-nWww.baidu.com

* Indicates that the package is discarded by the router. UDP is used by default. For security reasons, some routers are discarded by default.

Traceroute-W 1-n-tWww.soso.com// Use TCP

Reference

[1] Explain the commands

Http://linux.vbird.org/linux_server/0140networkcommand.php#netstat

[2] better explanation of TCP State, such as time_wait: the socket is waiting after close to handle packets still in the network.

Http://linux.die.net/man/8/netstat

[3]Http://www.linuxso.com/command/netstat.html

[4] traceroute usage example

Http://blog.sina.com.cn/s/blog_4895289e010009bn.html

Nice to talk about the ins and outs

Http://blog.chinaunix.net/space.php? Uid = 20172731 & Do = Blog & cuid = 159630

[5] ifconfig usage

Http://www.cublog.cn/u2/78880/showart_1879201.html