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Forum Discussion
Solved
R7500 Router DHCP address pool issues
The router is updated with the latest firmware (110). On both wired and wireless devices, some (often many) addresses end up as 169.x.x.x or 172.x.x.x addresses. I am using 192.168.1.x subnet. This especially happens with wired devices, but I can see in the attached devices list that wireless devices end up with these same incorrect address assignments.
This was not a problem prior to the latest firmware update.
I do not have another DHCP server running in the network.
I have two degrees in network engineering, as well as two degrees in computer engineering, and I am very familiar with networks and devices. This problem appears to be a firmware bug, but I am looking for some input. Is anyone else seeing anything like this on their R7500?
Resolved this problem. The network has an Ooma box on it for IP phone. This box is usually plugged into the internet cable modem, then the router plugs into the Ooma box. I use the ooma box attached to the router instead, with the router attached to the cable modem.
The Ooma box Cat cable was plugged into the "Network" plug instead of the "internet" plug. The Ooma box has a DHCP server inherent to the network plug, so a router plugged into it can obtain an address from it. This was causing rogue dhcp address request responses in a network configuration that did not match my network.
I swapped the cable to the internet plug, rebooted everything, all the incorrect addresses being handed out to all the devices on my network disappeared and everything looks good. I am still getting periodic drop of the wireless network for some reason, but that's a different problem.
2 Replies
> This was not a problem prior to the latest firmware update.
Reverting the firmware could confirm that.
> [...] This problem appears to be a firmware bug, [...]
It wouldn't be the first. If you'd like to probe further, these
routers often can be coaxed to allow command-line (shell) access to the
underlying GNU/Linux OS. A Web search for keywords like:
netgear telnet enable
should find more information. I use this: http://antinode.info/nte
Around here, for example (D7000, V1.0.1.50_1.0.1):
# ps | grep -i dhcp
1158 root 704 S /var/udhcpd_1 /etc/udhcpd.conf1
[...]
If a process like that went missing, then that could explain much.Resolved this problem. The network has an Ooma box on it for IP phone. This box is usually plugged into the internet cable modem, then the router plugs into the Ooma box. I use the ooma box attached to the router instead, with the router attached to the cable modem.
The Ooma box Cat cable was plugged into the "Network" plug instead of the "internet" plug. The Ooma box has a DHCP server inherent to the network plug, so a router plugged into it can obtain an address from it. This was causing rogue dhcp address request responses in a network configuration that did not match my network.
I swapped the cable to the internet plug, rebooted everything, all the incorrect addresses being handed out to all the devices on my network disappeared and everything looks good. I am still getting periodic drop of the wireless network for some reason, but that's a different problem.