We have problems with MT 3.30 and MSS correction on PPPoE…
generated rules seems like this:
38 D chain=forward action=change-mss new-mss=1440 tcp-flags=syn protocol=tcp
in-interface= tcp-mss=1441-65535
39 D chain=forward action=change-mss new-mss=1448 tcp-flags=syn protocol=tcp
out-interface= tcp-mss=1449-65535
but not doing anything …
after downgrade to 3.28 everything again OK
Are you sure it is not some kind of bugfix? Ehat problems did you had with 3.30?
It seems like rule is not processed … but counter in mangle is counting packets … Basicly this works like if we have MSS correction disabled … so no rewrite in header and users have problems with opening pages from servers using MTU 1500 …
It seems like rule is not processed … but counter in mangle is counting packets … Basicly this works like if we have MSS correction disabled … so no rewrite in header and users have problems with opening pages from servers using MTU 1500 …
Can anybody confirm this problem?
thanks and with best regards,
kabelfrei
Any update on this? 
We are expeiencing similar issues with mss correction on rb450g’s.
this seems to help, but it’s not very elegant:
chain=prerouting action=mark-routing new-routing-mark=to_pppoe-international passthrough=yes in-interface=LAN connection-mark=pppoe-out1_conn
chain=prerouting action=mark-routing new-routing-mark=to_pppoe-local passthrough=yes in-interface=LAN connection-mark=pppoe-out1_conn
I’m not 100% if its due to the same “bug”…
I had to change my PPTP Client interface’s max MTU (from the default of 1460 to like 1400) that was connecting to a server via a PPPoE connection in ROS v3.30. I can’t remember that I’ve had to do that when the router was running ROS v4.5. I had the change TCP MSS left on default (enabled) in both versions.