Computer network lab 1

how does one detect the MTU of the Gateway?

open the DOS window on the local machine and run: Ping-F-l 1472 192.168.0.1, where 192.168.0.1 is the gateway IP address and 1472 is the length of the packet. Note that the preceding parameter is "-l" (lower-case l), rather than "-1 ". If the packet can be pinged, it means that the packet does not need to be split and can be sent out through the gateway. If packet needs to be fragmented but DF set appears, the packet needs to be split and sent. In this case, reduce the packet length and then execute the ping command above. Try the packet length several times from 1400 to 1472. Add the packet length to the packet header by 28 bytes to obtain the MTU value. If the MTU value of the gateway is 1500, no modification is required. If the gateway has a firewall that cannot be pinged, set MTU to 1400. 4. How to modify the MTU of the Local Machine? The modification method is as follows: (1) Run regedit (2). Browse to: HKEY_LOCAL_MACHINE/system/CurrentControlSet/services/TCPIP/parameters/inte shielding words CES 2 (3) the inte shielding term CES has multiple sub-items, each of which corresponds to a network card. Select the NIC as follows: (a) determine the NIC used by the local machine to connect to the Internet or the IP address of the dial-up connection, for example, 192.168.0.19; (B) Click the Inte to shield the subitem on CES, view IPaddress items in the key-Value List. (c) if the key value of IPaddress is the same as the IP address in (a), that is, 192.168.0.19, this sub-item is the network card to be found. (4) enter the subitem, right-click the window on the right, choose "New"> "double byte value", enter the name "MTU", and press Enter. Double-click "MTU" and the modification window is displayed. 3: Enter the MTU value. Set the base number to decimal. After the configuration, You need to restart the machine to make it take effect.

MTU settings

Ethernet (common network, lan, optical fiber, etc.) 1500

Pppoe (for ADSL) 1492

Dial-Up (modem dialing) 576