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[FYI] DHCP Option 50 w/ Gargoyle 1.10.0

Posted: Mon Mar 05, 2018 3:04 pm
by setham
Hello,

First, thanks for all the work put in Gargoyle.

All my home devices have assigned a static IP outside the DHCP range (2-126), all new (so I can easily copy its MAC) or trusted-guest devices allowed into my network (not to be confused with my Guest SSID) are assigned an IP from a different range (129-150) within a /24 network.

I have selected Enforce "DHCP assignments".

This configuration worked fine until last week when a new device did not obtain the assigned static IP after its DHCP renew, I restarted the device, rebooted the router, nothing.

I did some packet capture and found that the device was sending DHCP Option 50 with the IP address assigned when it first connected to the router, and the router running gargoyle 1.10.0 complied assigning the requested IP (x.y.z.130) even though it has already a static IP for that MAC.

Once I realized the issue, I temporarily modified the Dynamic DHCP range to a range that did not include the IP requested by DHCP Option 50 (200-205), which led to the device be assigned the correct static IP.

- Shouldn't the DHCP server ignore the Option 50 request and assign the corresponding static IP?
- Am I misunderstanding Option 50? From what I read it is a request, not a required/mandatory assignment


Thanks

Re: [FYI] DHCP Option 50 w/ Gargoyle 1.10.0

Posted: Mon Mar 05, 2018 10:30 pm
by Lantis
You might need to increase the log level of dnsmasq and capture it to find out exactly what is going on.
I can only hazard to guess that the enforce DHCP assignments rule is causing you a problem. I would try with that off and see what results you get.