Some IOT clients not accepting dnsmasq DHCP offer

Expected Behaviour:

clients configured for DHCP should accept the address offered by dnsmasq

Actual Behaviour:

I have 2 clients, ip cameras
one is a cheapo Chinese device
another is from a well known brand in CCTV, Geovision.

Both devices don't accept the ip address offered by dnsmasq.

As a test, I setup a cisco router with default settings, both cameras get an address from the router.

Dropping the cameras back into my "normal" LAN, no more dhcp for the cameras.
I added the option 'log-dhcp' to the dnsmasq config file, log output is here : Log exerpt

Debug Token:

ebweurmp9w

Try factory resetting your device(s).

From the log, It looks like dnsmasq sees the DHCP request, offers an IP to your Geovision device and sends the DHCPACK response with the information packet.

It's also requesting 53, 58 and 59.

From DHCPACK perspective, it sends out everything that's needed for the client to get the information.

See if factory reset helps. I had some issues with devices that would not pick up the IPs myself and most of the times, factory resetting them worked.

Also if you have them connected via router/switch, power cycle anything in between camera and Pi-hole

I already have power-cycled the entire chain of devices between clients & Pi-Hole, multiple times, over the past months of chasing this issue.

I had decided to blame the cheapo China Export camera, until today.
The Geovision device has the same issue, but I have hopes that tech support from Geovision will be helpful when I get to them with this.

So, the 2nd camera is brand new since today, had already reset it anyway, as soon as I discovered the problem.
The China Export camera has had the bejeezus factory reset out of it, over the months.

Next experiment for me is setting up a Raspberry Pi as dnsmasq-dhcp server in lab environment, and giving that a go.

Any ideas are welcome!!

I already assumed you have this set-up via Pi-hole.

There is not difference between Pi-hole's DHCP (which is via dnsmasq anyways) or standalone dnsmasq.
Try giving FTLDNS beta a spin. It does not rely on dnsmasq any more.

I've been using it for quite some time now and it's as stable as it can get.

Just a point of correction, FTLDNS uses the dnsmasq base code, we just include some more hooks to use for our needs. If the dnsmasq package is not working then I would say it is very likely that FTLDNS will not work either.

1 Like

So i tested these 2 reluctant clients against a 'generic' Debian installation and a Raspbian installation of Pi-Hole.
No issues to be reported, unfortunately for me :frowning: .

For the sake of completeness, the Pi-hole that is giving me grief with these clients , is running in a virtual environment.

Next, I will setup another Pi-hole in the hypervisor, and test some more.

update : so i setup another virtual machine, minimal debian with Pi-hole on top. Same issue.

Can anyone come up with any reason why DHCP would not work as expected when hosted in a VM ?
Most clients are getting an ip address, just some not.
The ones that aren't getting addresses happen to be a mix of Chinese IP cameras running some form or other of embedded Linux.

Any thoughts would be welcome...

Try going with a different OS on the VM (maybe Ubuntu?).

You can try to set the Static reservation within the Pi-hole's DHCP settings for the MAC addresses of those cameras, and see if they pick it up the IPs like that.

1 Like

The VM client OS is Debian, Ubuntu wouldn't make much of a difference, since dnsmasq would remain the DHCP server.

Was one of the 1st things that I tried. No joy.

This is turning out to be unrelated to Pi-Hole, and even unrelated to dnsmasq.
In a test setup, I used a Win10 machine with http://www.dhcpserver.de handing out addresses, guess what :
the devices are still refusing to ACK the dhcp offer.

Wiresharked the bejeezus out of the dhcp-transaction and sent the captures to Geovision tech support. Hopefully they will invest some time into this.

It could be that the build for the environment is different.

In between your first post and this, we released Pi-hole v4.0 (you might want to give that a spin - upgrade with pihole -up)

I ... doubt it ...

My Pi-hole is updated, same issue.

Setting up a virtual Ubuntu for testing. Can't hurt to try :stuck_out_tongue:

The company I work for has access to 2nd line tech support with Geovision, so again : Can't hurt to try :stuck_out_tongue:

1 Like

fwiw, Ubuntu+dnsmasq has the same symptom.

so, i installed isc-dhcp-server which uses DHCPD i guess, and things work... on the ubuntu VM.
i'm lost now.

This topic was automatically closed 21 days after the last reply. New replies are no longer allowed.