Change TCP MSS

RouterOS General
1

i am having a problem with very slow uploads from a ROS3.14 router through a Metro Ethernet circuit, Downloads are good. That circuit is being shared with another company by using vlans. The other company is using Cisco Gear and thery were having weird problem until they adjusted their TCP MSS. How do i make the same adjustments using ROS? Here is what the “other comapny” provided me with as an example:

interface Vlan804
description PTP_to_EQC for Admin Traffic
ip address 172.25.186.6 255.255.255.252
ip mtu 1460
ip tcp adjust-mss 1300

I have tried adjusting the MSS using mangle however i have not had any success.

Please provide me with the proper ROS example


Thank You

2

Make mangle rule with chan-forward, protocol- 6(tcp) and out-interface your vlan interface. In action use change MMS and new TCP MSS put 1460 or what ever you would want the MSS to be. However this said. Your Vlan would run through a PPPoE, PPTP or similar connection. This has got a tick that will automatically correct your MMS and does a very descant job of it. Rather try this firs.