[Dnsmasq-discuss] not getting a subnet-mask in dhcp reply, when using multiple instance of dnsmasq

[AleksM]

thanks Brian,

perhaps the backstory might be interesting - by the time i emailed the list
here, it was after a while of trying to troubleshoot and try different
things (the ol' throw-enough-sh*t at the wall and maybe something will
stick-approach. def not the brightest idea on my part).

i added the dhcp-option= part when i was getting desperate about not
getting the subnet correctly, but by then i had I failed to realize the
impact of earlier adding dhcp-option-force as it was in there from before,
for a different reason (i thought it would bypass the
is-there-a-dhcp-server checks openwrt does before starting up)..

i just checked the man page (admittedly something I probably should have
done earlier) and realized that dhcp-option-force=lan,1 means option 1
(subnet) is affected.. i'm not sure what the outcome was supposed to be of
having both (sems to be allowed?), but it seems the option 1 was not sent
at all regardless of client querying for it then (i was informed on the
forum linked before that it was due to the force though).. i removed it and
the right subnet started to appear, so i got rid of both and lived happily
again (well, until the next issue i end up running into).

On Tue, 19 Sept 2023 at 15:20, Brian Davidson <davidson.brian at gmail.com>
wrote:

> You appear to have competing settings for subnet.
>
> dhcp-option=lan,1,255.255.255.0
> dhcp-option-force=lan,1
>
> Is it intentional?
>
> On Tue, Sep 19, 2023 at 9:28 AM AleksM <a+dnsmasq at alek.cx> wrote:
> >
> > Hi all,
> >
> > I'm running on OpenWRT (SNAPSHOT r23935+13-c1206675a4) which has
> installed dnsmasq 2.89 and my client is a macbook running MacOS 12.3.1 and
> I recently switched from a single dnsmasq instance to a multi-instance
> dnsmasq setup (because i wanted a different subdomain name given for the
> different networks i have dnsmasq listen on and that was the approach
> suggested in openwrt forum),
> >
> > But when i performed this change, i found out (after many days of
> troubleshooting) that the dhcp response no longer contained a subnet-mask
> field (which was causing my client to use the default /16 for a classful
> CIDR of that address space, which caused connectivity issues that were
> hilariously baffling at first).
> >
> > Is there some bug here, or am I doing something wrong?
> >
> > Attaching both the single-instance dnsmasq.conf (working) and the
> DHCPOFFER response as well as the offending instance in the multi-instance
> dnsmasq.conf (broken) and the DHCPOFFER response, where the subnet-mask
> option is omitted (despite me attempting to add it as an extra DHCPOPTION
> #1 even!)
> >
> > Any advice or anything else to look at?
> >
> > Warm regards,
> > Aleks
> > _______________________________________________
> > Dnsmasq-discuss mailing list
> > Dnsmasq-discuss at lists.thekelleys.org.uk
> > https://lists.thekelleys.org.uk/cgi-bin/mailman/listinfo/dnsmasq-discuss
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.thekelleys.org.uk/pipermail/dnsmasq-discuss/attachments/20230919/c90d797b/attachment.htm>