Hi,
Please, I have a location behind IPSEC (Mikrotik). Some WEB pages and applications don’t work, we discovered that it is an MTU size problem.
How we can change MTU on all devices? We try DHCP option:
/IP dhcp-server
add code=26 name=mtu1410 value="'1410'"
It looks like windows 7 refuse to accept this option. Or dhcp option 26 in mikrotik doesn’t work?
Thank you for any advice.
Option is sent only if dhcp client requests it. Maybe windows client simply does not use that option, you can verify this by running packet sniffer and checking what client requests. DHCP logs on ROS should also list requested options.
It is probably better to use a “Change MSS” mangle rule to reduce the MSS option in all TCP SYN packets being
forwarded. This should at least solve the problem for TCP.