Re: SRX300 TCP-MSS

You can verify if setting the tcp-mss/MTU is working by the tcpdump command in the shell
> start shell
> tcpdump –i (eth interface) host (host ip)
MSS is set only during tcp 3-way handshake and is part of the "TCP Options" field of tcp header only for SYN packets.

For example:

11:23:44.450420 IP 83.72.75.223.20614 > 95.233.23.13.80: Flags [S], seq 3483318893, win 65535, options [mss 1460,nop,wscale 4,sackOK,TS val 2479291524 ecr 0], length 0
11:23:44.451946 IP 95.233.23.13.80 > 83.72.75.223.20614: Flags [S.], seq 425754303, ack 3483318894, win 0, options [mss 1460], length 0
11:23:44.522227 IP 83.72.75.223.20614 > 95.233.23.13.80: Flags [.], ack 1, win 65535, length 0
11:23:44.523656 IP 95.233.23.13.80 > 83.72.75.223.20614: Flags [.], ack 1, win 5840, length 0