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23.1 Legacy Series / Re: Multi-WAN no graceful recovery
« on: May 05, 2023, 07:39:24 pm »If that was the source of the block, would that not ALSO apply after a reboot? Rebooting corrects the issue. And FYI that is a default and recommended block on most internet facing WAN interfaces.
True, however generally for a WAN interface, where that option is used, the expectation is that NO communication w/ an RFC1918 / non-routable IP address would be necessary / desired.
Just a guess, but I could envision a reboot working due to something like the order of operations differing at boot time. For example, perhaps at boot time, the DHCP lease request is sent before that WAN rule is loaded. It would probably take a code review to determine the order of operations, and how it might differ during the boot cycle vs. when an interface is downed/upped to know for sure.
As a test / possible fix, I suggest you disable the block RFC IPs on WAN option, and instead add a custom WAN rule that blocks all RFC1918 IP sourced traffic to your WAN interface, but explicitly allow traffic to/from your ISP's DHCP server RFC1918 IP you mentioned, source or dest ports of UDP 67 and 68 (for IPv4).
If that does not fix the issue, then something else is at play (in which case I would look at the advanced DHCP request settings, as some ISPs can be very finnicky on the request parameters. Start by searching your preffered search engine for other customers of the same ISP w/ non-standard edge routers / firewalls).
Ultimately though, since you know that you need to be able to receive traffic from an RFC1918 IP in order to receive your DHCP lease from your ISP, it seems logical that you would not be able to leverage the option for blocking all RFC1918 IP space into your WAN interface, and leaving it enabled should be expected to lead to inconsistent results / problems. GL!