Firewall anti-replay option per policy
When the global anti-replay option is disabled, the FortiGate does not check TCP flags in packets. The per policy anti-replay option overrides the global setting. This allows you to control whether or not TCP flags are checked per policy.
To enable the anti-replay option so TCP flags are checked using the CLI:
config firewall policy
edit 1
set name "policyid-1"
set srcintf "wan2"
set dstintf "wan1"
set srcaddr "all"
set dstaddr "all"
set action accept
set schedule "always"
set service "ALL"
set anti-replay enable
set logtraffic all
set nat enable
next
end