Firewall rules not working as configured

[seed]

Today I converted my mail server to dualstack and therefore added the IPv6 address to the alias in the WAN rule. However, no tcp handshake was established (the syn-ack couldnt "get out").


After several hours of searching, I recreated the exact same rule and suddenly it worked.

How can this happen?

[doktornotor]

See Firewall - Diagnostics - States - Actions.

[seed]

I even rebooted the machine without luck. If it was a state issue the reboot should have solved it.