I've been having some problems trying to get a PPTP connection to work ... here's the basic setup:
* central site has a fixed IP on a cable modem, I forward PPTP to the MikroTik behind it; MTU on that physical link is 1492
* remote site is on a dynamic IP also with NAT; MTU in the test is 1500, but in production could be lower (down to ~1440)
PPTP connection is coming up fine, bridging of LAN segments between the two locations also works fine - except for actual Internet access. I'm assuming MTU problems, but all the attempts to limit the MTU on LAN segment interfaces, the bridge interface or where ever else failed. The devices have these interfaces in use:
* central: WAN uplink (eth3), LAN segment (eth2), PPTP, bridge (with the eth2 and PPTP in it)
* remote: WAN uplink (eth1), LAN segments (eth2, eth3), PPTP, bridge (with eth2, eth3 and PPTP in it)
What do I have to do to actually get the end devices adjust their MSS to what will go through the PPTP connection? Do I need to set up some firewall rule to get the router to force reduction of MSS?