[Dnsmasq-discuss] Failing to get DHCP responses on OpenBSD
dnsmasq at mailfri.com
Sat Dec 7 23:29:45 GMT 2019
On Sat, 7 Dec 2019 21:44:08 +0100
Geert Stappers <stappers at stappers.nl> wrote:
> A. stop dnsmasq and check again what fstat says about port 67
Nothing else is listening on that port.
> B. try only 1 interface (add the others I/F when 1 works)
Could not make that work. :-(
> > inet 184.108.40.206 netmask 0xffffe000 broadcast 220.127.116.11
> netmask and broadcast don't match. Make the broadcast 18.104.22.168
> to match the netmask
Sorry, my mistake, I had replaced the real IP address by some made up
I was playing around a bit more with fstat and netstat and noticed one
difference between dhcpd and dnsmasq - dhcpd binds to bpf (Berkeley
Packet Filter) and not a datagram socket like dnsmasq does. I
definitely see a UDP datagram coming in for port 67 with tcpdump when
dhcpd is running and it is replying instantly with a UDP datagram. So
something makes the bpf socket see the traffic while the datagram
socket does not?
OTOH, why would I be the only OpenBSD user that has that issue? Maybe
there is some fancy OpenBSD security mechanism that I am not aware of?
When I run dnsmasq for testing, I am running as root. Running it with
the regular rc scripts, it runs with user _dnsmasq. I am getting the
same behavior from dnsmasq in both cases however.
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