1:FORWARD,OUTPUT,POSTROUTING
2*mangle
3-j TCPMSS;;FAIL
4-p tcp -j TCPMSS --set-mss 42;;FAIL
5-p tcp -m tcp --tcp-flags FIN,SYN,RST,ACK SYN -j TCPMSS --set-mss 42;=;OK
6-p tcp -m tcp --tcp-flags FIN,SYN,RST,ACK SYN -j TCPMSS --clamp-mss-to-pmtu;=;OK
7