[Dnsmasq-discuss] DHCP server not assigning IP to RTMU86

[Nicolas Cavallari]

On 11/05/2022 13:41, Kamil via Dnsmasq-discuss wrote:
> 
> But when I used isc-dhcp-server with following config:
> 
>     subnet 192.168.6.0 netmask 255.255.255.0 {
>              interface eth0;
>              ddns-update-style none;
>              default-lease-time 600;
>              max-lease-time 3600;
>              authorative;
>              range 192.168.6.11 192.168.6.20;
>              option subnet-mask 255.255.255.0;
>              option routers 192.168.6.1;
>              option domain-name-servers 8.8.8.8;
>              get-lease-hostnames true;
>              use-host-decl-names true; 
> 
>     }
> 
> 
> then isc-dhcp-server assigns correct IP to RTMU86.
> Why doesn't Dnsmasq want to assign IP to RTMU86?

Your isc-dhcp-server config includes "authoritative" while your dnsmasq 
doesn't include "dhcp-autoritative".

There isn't enough information to determine what is going on here, but
I had problems with broken DHCP clients sending DHCPREQUEST without a 
server identifier option.
RFC-compliant DHCP servers ought to ignore them, but authoritative mode 
is here to override this behavior.

dnsmasq does not log anything in non-authoritative mode when it drops 
DHCP requests.

If anything else fails, use tcpdump/wireshark.