(Sorry I completely missed this thread 
)
Thank you for reporting and writing down an excellent issue!
I fear the proposed solution will not work on many installation where the FQDN of the machine is not the one used by LAN clients to access the gateway itself.
From my experience, I could say that more than 50% of installations have a bad FQDN on firewalls.
We should find a solution which fit any usage scenarios without breaking existing installations.