What is MTU, how to detect and set the router MTU value

The MTU is the abbreviation for Maximumtransmissionunit.

The maximum packet that is transmitted over a network. The unit of the MTU is bytes. Most network devices have an MTU of 1500. If the MTU of this machine is larger than the MTU of the gateway, large packets are removed and sent, resulting in a lot of packet fragmentation, increased packet loss rate, and reduced network speed. The MTU of the machine is set to be smaller or the same than the MTU of the gateway, and the packet loss can be reduced.

How do I detect the MTU of a gateway?

On this computer, open the DOS window and execute:

ping-f-l1452192.168.1.1

Where 192.168.1.1 is the IP address of the gateway, 1452 is the length of the packet. Note that the above argument is "-l" (lowercase L) instead of "-1". If you can ping, indicating that the packet does not need unpacking, can be sent through the network Guan Fa. If it appears:

Packetneedstobefragmentedbutdfset.

Packetneedstobefragmentedbutdfset.

Packetneedstobefragmentedbutdfset.

Packetneedstobefragmentedbutdfset.

Indicates that the packet needs to be split to send. At this point, reduce the packet length, and then execute the ping command above. Try a few more times from 1400 to 1472 to find the right packet length. The value of the MTU is obtained by adding a packet length of 28 bytes to the packet header. If the MTU value for the gateway is detected to be 1500, no modification is required. If the gateway has a firewall ping, try to set the MTU to 1400 directly.

c:documentsandsettingsadministrator>ping-f-l1452192.168.1.1

Pinging192.168.1.1with1452bytesofdata:

Replyfrom192.168.1.1:bytes=1452time=5msttl=64

Replyfrom192.168.1.1:bytes=1452time=5msttl=64

Replyfrom192.168.1.1:bytes=1452time=5msttl=64

Replyfrom192.168.1.1:bytes=1452time=1msttl=64

The result is a response! This indicates that the MTU value is feasible! However, it is strongly recommended to find the maximum MTU value possible! This way, in the setting, you can achieve the best speed!

Find the MTU value: Using the above method to find the value is not the MTU Oh! Due to some of the problems above, the above value plus 28 is the MTU value we need! So, in the example above, the MTU value we need is 1464+28=1492!

Note: I set to 1452+28=1480, or there will be some sites can not open, Remote Desktop can not log through the domain name of the problem (via IP normal Remote Desktop Landing), and the MTU set to 1452, but these problems are solved, and, at this time, landing zlbog normal background , the use of domain name Landing Remote Desktop Normal.

Generally speaking, the design of the local MTU value, you can solve some of the site will not open the situation, but if your shared host or router's MTU settings are problematic, sometimes the problem still exists or, or the situation of slow network speed. Reasonable set up the router and the MTU value of the machine, you can completely solve the above problems, so that the speed of the Internet to maximize.

How do I modify the MTU of my computer? The following methods are modified:

(1), run regedit

(2), browse to: hkey_local_machinesystemcurrentcontrolsetservicestcpipparametersinterfaces

(3), interfaces has more than one subkey, each subkey corresponds to a network card. Please select the network card as follows:

(4), to determine the computer used to connect the Internet network card or dial-up connection IP, such as 192.168.0.19;

(5), click on the interfaces on the mouse to see the key value list of IPAddress items;

(6) If the key value of the IPAddress is the same as the IP in (4), that is 192.168.0.19, the subkey is the NIC to be found.

(7), enter the subkey, in the right window, press the right mouse button, select "New"-> "Double byte value", enter the name "MTU", press ENTER. Then double-click "MTU" with the mouse and pop up the Modify window: Figure 3: The value of the MTU is filled in. Please set the base to decimal before filling in. Once set, the machine needs to be restarted to take effect.

Practice, restart, test, finally come to the best network status, explore without limit, efforts, will have good results.