R7900, external DHCP server, and guest networks with no route to internet
Ok, here's the deal. I've got DHCP (dnsmasq) running on a server on my network. DHCP on the router is turned off. For wired clients and wireless clients on the primary wireless SSIDs, everything works as expected. Clients pull an IP, and receive the gateway, DNS server, NTP server, and NetBIOS nameserver information via DHCP options. The options are all addresses to servers on my network. These clients route out to the internet just fine.
The problem is with wireless clients on the guest networks. They pull an IP, and receive the same options as the other clients, but have no route out to the internet. Any attempt to access the internet results in these clients just timing out. They do, however, show up in the list of connected devices in the router dashboard.
My theory is that the R7900 does some internal routing between the primary and guest networks, and, when it is the DHCP server, it sends out different DHCP options (diferent gateway? different subnet?) to clients, depending on whether they are connecting to a primary or a guest SSID. As far as I can tell, this process is opaque and internal to the router.
Has anybody else encountered this issue? If so, can it be worked around? Even information on how the R7900 internally configures its primary and guest networks would be helpful.
Thanks in advance.