Linux Network Communication commands

Linux Network Communication commands

------------------------------------- Network communication command allow 1: write function: Send a message to a user (the other user must log on and cannot receive it) scenario: 1: now there are two users working on the linux Server: root, leyangjun 2: root in Beijing leyangjun in Shanghai 3: Both of them log on to the system at the same time to communicate with QQ, real-time communication root: write leyangjun (write command) this is my test, hello! (Written content) ctrl + d end input leyangjun: Message from leyangjun @ helen... information this is my test, hello! This message is the second message sent by the root: wall (all user) function: broadcasts information to all users, and everyone on the server can receive the broadcast content. Example: wall leyangjun hao Man! Ctrl + d end 3: ping test network connectivity ping 192.168.11.1 different from Windows, as long as you do not press ctrl + c, it will not stop pinging. ping-c 3 192.168.11.1 indicates pinging the host 3 times. Introduction c indicates the number of times. The default ping time is 64 bytes ping-s 65507 192.168.11.1 (ping packet ). the maximum byte is 65507 bytes) experience Sharing: note that sometimes you can ping the response packet to prove that there is no problem with the network. 1: first, let's look at the icmp response speed. The value of time is 2: Observe the packet loss rate, 0% packet loss share: during a project test, once or twice the data could not be entered into the database. At that time, we finally changed the root network cable to solve the problem. Why? A: The low-end wire measuring instrument can only test whether the network cable can be connected. It is okay to enable a light connection, but the packet loss rate cannot be measured. Sometimes packet loss rate occurs: when the network cable is stretched in the warm winter or in the cold summer, cable contact may cause packet loss rate, including packet loss rate due to NIC failure in many cases. Check your network cable and network device. 4. View network settings in ifconfig (view the IP address of the host) -a: the information of all NICS is displayed. eth0 is the IP address corresponding to your actual Nic information ifconfig eth0: Inet addr: 192.168.1.55 change IP Address: ifconfig eth0 192.168.9.56 (you will find that, at the next restart, the original IP address is not the IP address you changed, because it is not written to the file you want to configure)