Cannot get dhclient to get an IP address on WAN

[ipartola]

I tried that already. I can actually verify that their DHCP servers don't care if there is an active lease: I can just keep requesting new IP addresses using different MAC addresses and I see new offers with new addresses. The issue is that dhclient is either not getting or ignoring DHCPOFFERs.

From doing a bunch of web searches it seems that the issue might be VLAN tagging related. In tcpdump I can see that the incoming traffic comes in as VLAN 0. Some online posts suggest that stripping this tag may help: https://www.reddit.com/r/PFSENSE/comments/9l7my1/dhcp_client_not_working_on_wan_att_fiber_dhclient/e76dj12/?utm_source=reddit&utm_medium=web2x&context=3

[ipartola]

Looks like pfsense has a similar issue: https://redmine.pfsense.org/issues/8526 with a still open pull request https://github.com/pfsense/FreeBSD-src/pull/9. I think this matches exactly what I'm experiencing with OPNSense. How can I report this bug upstream?

[franco]

We are already doing write VLAN skip so I guess it would be fair to say we could implement read VLAN (0) skip although that is pretty mean from the ISP to use that reserved non-VLAN but priority trick and there is no base network support for this so whenever the ISP decides to bump priority of a packet outside of DHCP/dhclient with this it's not going to end well. ;)

Discussion at https://github.com/opnsense/src/issues/114


Cheers,
Franco

[ipartola]

Thanks again Franco! With some more testing I see that they use any which VLAN or sometimes no VLAN at all. No matter what I do I still can't get it to work, whether directly, through a dumb switch, etc. I am going to keep complaining to the ISP about this, but in the meantime I gotta get work done and have the rest of the house be able to get online so back to OpenWRT I go, at least for now.