【Router】Why there are some websites cannot be accessed using Ruijie Router?

There are some specific websites cannot be accessed when using Ruijie Router. Change to a small home router, returned to normal, DNS and network communication issue has been excluded.

Reason:

When the PC visits the Web, it will establish a connection with the server through the TCP three-way handshake and transmit the data (don’t fragment). In this process, the maximum transmission value of the TCP MSS will be negotiated. If the intermediate device is not set specially, the MSS value may be negotiated Large, and the operator filter the data during the data transmission (TCP MSS is too large, plus the head and other fields, beyond the MTU 1500 length).

Solution:

Need to configure the following command (ip tcp mss) on the three-tier equipment, so that when the data pass through, it will automatically modify the MSS value when negotiated.

Router(config-if-GigabitEthernet 0/1)#ip tcp adjust-mss 1200                         

//If the general environment can be configured 1460 (ip and TCP head of each 20 bytes), if the PPPOE environment, configuration 1452.