DHCP (Lan side) problem

[Lazybummm]

I have 3 T-mobile AC1900 (ac68u) routers. One is being used as a router and the other two as hard wired access points. The router unit has been properly flashed to Asus firmware and is also flashed to Asuswrt-Merlin.

I've had this setup running for probably about 1.5 years without any problems. In the past month or so, several of my devices on DHCP (lan side) is not able to get an IP and does not connect to the network. Once I change the device to manual IP and assign one, the device gets on the network fine. I do have quite a few clients, I'm not sure what is going on.

I'm beginning to suspect it's a DHCP lease issue? I honestly don't know how it works. If a new device signs onto wifi, the router assigns an IP, does that device "take over" the IP for a "leased time" thus no other device will be assigned that IP until lease time is up? that doesn't quite make sense. Any help appreciated.

I'm still running an older version of Asuswrt-Merlin, 380.65_4. Any advice appreciated. Thanks.

 

[ColinTaylor]

Try looking in the router's syslog for error messages when the devices fail to connect properly.

How many devices are connecting to these routers/AP's, 10's, 100's?

 

[Lazybummm]

Try looking in the router's syslog for error messages when the devices fail to connect properly.

How many devices are connecting to these routers/AP's, 10's, 100's?

Thanks for the tip. I have according to Asus 29 active clients (I haven't counted), but I don't think more than 50. Here is the error I got: Is this NVRAM being full?

Jul 29 21:02:54 dnsmasq-dhcp[27406]: DHCPOFFER(br0) 192.168.20.174 8c:xx:xx:xx:xx:xx
Jul 29 21:02:54 dnsmasq-dhcp[27406]: failed to write /var/lib/misc/dnsmasq.leases: No space left on device (retry in 60s)
Jul 29 21:02:54 dnsmasq-dhcp[27406]: DHCPREQUEST(br0) 192.168.20.174 8c:xx:xx:xx:xx:xx
Jul 29 21:02:54 dnsmasq[27406]: failed to allocate 124 bytes
Jul 29 21:02:54 dnsmasq-dhcp[27406]: DHCPNAK(br0) 192.168.20.174 8c:xx:xx:xx:xx:xx no leases left

 

[adampk17]

We’re not supposed to be discussing issues with T-Mobile routers flashed with Merlin firmware, right?

 

[ColinTaylor]

We’re not supposed to be discussing issues with T-Mobile routers flashed with Merlin firmware, right?

Not exactly. Merlin will provide absolutely no support, and any discussions about conversion processes will be deleted. IMHO that doesn't stop other people discussing generic issues that are not T-Mobile specific (He's running a very old version of Merlin from before the lock-down).

 

[ColinTaylor]

@Lazybummm On the face of it your router has run out of memory so it can't create the lease entries. When was the last time you rebooted the router? Try that.

There have been other occasional reports of this problem but the cause was never established.

 

[Lazybummm]

@Lazybummm On the face of it your router has run out of memory so it can't create the lease entries. When was the last time you rebooted the router? Try that.

There have been other occasional reports of this problem but the cause was never established.

Thanks again! I rebooted it last night, it has been running without a reboot for a long time (I've not manually rebooted for months, unless it restarted itself at some point, which I doubt). I will checkout the other reports