VPN IPSec MSS

Hello,

I have 2 MTU settings on my CCR1036 with the latest OS

/interface ethernet
set [ find default-name=ether1 ] mtu=1472 name=WAN

in addition I created a mangle rule with a lower MSS for traffic inside the VPN tunnel based on a forum post

add action=change-mss chain=forward comment=“pmtu_GREG” dst-address=10.208.217.0/24 log=yes log-prefix=“pmtu_GREG”
new-mss=1350 passthrough=yes protocol=tcp src-address=10.160.200.16/28 tcp-flags=syn tcp-mss=!0-1350

When I ping with the srcnat. adress 10.160.200.17 to dst adress 10.208.217.249 packets are only fragmented if the ping size is set higher as 1406.

What I have done wrong?
regards
Achim

MSS can be adjusted only for TCP traffic. Ping is not TCP, so it is not affected by that rule.

mea culpa… I was confused with ip vs tcp…

Thanks
Maedo