DHCP renew on WAN not working

mtis

Hi.

I've just moved my home router from OpenWrt on a GL.iNet GL-MV1000 to pfSense on an Intel NUC12 with 2x NICs. I've used pfSense a lot at work so am pretty familiar with it. I have several issues which I'll create separate threads for. This is the first and most important.

DHCP renew on the WAN is not working. My ISP issues an IP with 600 seconds lease time. I can see in the logs after 300 seconds DHCPREQUEST packets being sent out to the server. There's never a response. After 300 seconds, the lease has now expired, I get a DHCPACK with a new lease, which is very often a new IP. Does pfSense do something different with regards to DHCP renewals? I'm wondering if my ISP requires renewals to be broadcast like the initial request - is this something I can configure?

Thanks.

stephenw10

Yes. Some ISPs have DHCP relays that only respond to broadcasts which seems broken to me but.... not much you can do.

Set the DHCP option: supersede dhcp-server-identifier 255.255.255.255

See for example: https://forum.netgate.com/topic/185334/pfsense-wan-gateway-randomly-goes-down

mtis

@stephenw10 Amazing, thank you for the quick response

keyser

@mtis This issue might also be caused by the ISP requiring DHCP renew requests to be QOS marked or VLAN Priority tagged. I have a french ISP that requires all DHCP frames to Priority 6 vlan tagged - otherwise they just don’t reply to the frames.
Do you have any chance of doing a packet capture of the ISP’s CPE doing DHCP discover and renew? Then you could see what they might be doing (if not just requiring renews to be broadcasted).