Port 68 UDP neccessary for DHCP?

[snoopy]

I recently moved to a provider with DHCP assigned external address, and I noticed that unless I open incoming port 68 UDP on Wingate's firewall, Wingate machine cannot get a dynamic address, and "intrusion" from my provider's DHCP server is logged in firewall log. Is this port really neccessary? I've never had to open it on Linux, Windows machines or hardware routers, and they worked fine with DHCP.

[genie]

Yes, it is necessary - your provider uses DHCP protocol to allocate your machine with an IP address so DHCP packets must be able to reach your machine.

[adrien]

those other devices must have been opening port 68 for the DHCP response packets. DHCP specification required all responses to come back on port 68.

Regards

Adrien