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

[Kamil]

On Sun, May 15, 2022 at 01:10:40AM +0200, Kamil via Dnsmasq-discuss wrote:
> > On Sat, May 14, 2022 at 11:27:34AM +0200, Geert Stappers via
> Dnsmasq-discuss wrote:
> > > On Sat, May 14, 2022 at 02:53:51AM +0200, Kamil via Dnsmasq-discuss
> wrote:
>   ...
> > > > 1. I plug one device - it works.
> > > > 2. I unplug it and plug the RTMU86 - doesn't work.
> > > > 3. I Unplug RTMU86 and plug any other device - it works.
> > > >
>   ...
> > > Be yourself, accept yourself. Full focus on the challenge that you are
> > > facing.
> >
> > Sure
> >
>
> What proof is available of
> the RTMU86 sending DHCP packages
> when pluging the ethercable back in?
>

RTMU86 has a led indicator that is lid when the address has been assigned
to it.
1. If I plug RTMU86 to the home router - the led is on, I can find its IP
in the router's lease list and I can ping this IP
2. If I plug RTMU86 to the RPi with isc-dhcp-server configured - the led is
on, I can find its IP in the  isc-dhcp-server's lease list and I can ping
this IP
3. If I plug RTMU86 to the RPi with Dnsmasq configured - I can use tcpdump
which gives me this output (I changed MAC  addresses):
> 16:17:31.125779 IP 0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP,
Request from fa:XX:XX:XX:XX:1c (oui Unknown), length 300
So I presume that  RTMU86 indeed sends DHCP packages, but the led is off
and I can not find it in the Dnsmasq lease list.

Full tcpdump log (with changed MAC addresses) below:
> 16:17:28.175124 IP6 :: > ff02::16: HBH ICMP6, multicast listener report
v2, 2 group record(s), length 48
> 16:17:28.187120 IP6 :: > ff02::16: HBH ICMP6, multicast listener report
v2, 4 group record(s), length 88
> 16:17:28.199412 ARP, Request who-has 192.168.6.1 tell 0.0.0.0, length 28
> 16:17:28.235076 IP6 :: > ff02::16: HBH ICMP6, multicast listener report
v2, 4 group record(s), length 88
> 16:17:28.483118 IP6 :: > ff02::1:fffb:fe9: ICMP6, neighbor solicitation,
who has fe80::XX:XX:XX:fe9, length 32
> 16:17:29.507285 IP6 fe80::XX:XX:XX:fe9 > ff02::16: HBH ICMP6, multicast
listener report v2, 5 group record(s), length 108
> 16:17:29.507966 IP6 fe80::XX:XX:XX:fe9 > ip6-allrouters: ICMP6, router
solicitation, length 16
> 16:17:29.519049 IP6 fe80::XX:XX:XX:fe9 > ff02::16: HBH ICMP6, multicast
listener report v2, 1 group record(s), length 28
> 16:17:29.891065 IP6 fe80::XX:XX:XX:fe9 > ff02::16: HBH ICMP6, multicast
listener report v2, 5 group record(s), length 108
> 16:17:30.019064 IP6 fe80::XX:XX:XX:fe9 > ff02::16: HBH ICMP6, multicast
listener report v2, 1 group record(s), length 28
> 16:17:30.077265 IP6 fe80::XX:XX:XX:fe9.mdns > ff02::fb.mdns: 0*- [0q]
2/0/0 (Cache flush) PTR myhost.local., (Cache flush) AAAA
fe80::XX:XX:XX:fe9 (139)
> 16:17:30.151935 ARP, Request who-has 192.168.6.1 tell 0.0.0.0, length 28
> 16:17:31.125779 IP 0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP,
Request from fa:XX:XX:XX:XX:1c (oui Unknown), length 300
> 16:17:31.728625 ARP, Request who-has 192.168.6.1 tell 0.0.0.0, length 28
> 16:17:32.152301 IP6 fe80::XX:XX:XX:fe9.mdns > ff02::fb.mdns: 0*- [0q]
2/0/0 (Cache flush) PTR myhost.local., (Cache flush) AAAA
fe80::XX:XX:XX:fe9 (139)
> 16:17:33.510623 IP6 fe80::XX:XX:XX:fe9 > ip6-allrouters: ICMP6, router
solicitation, length 16
> 16:17:33.730051 ARP, Request who-has 192.168.6.1 tell 192.168.6.1, length
28
> 16:17:33.739141 IP 192.168.6.1 > igmp.mcast.net: igmp v3 report, 1 group
record(s)

PS. I've read in FAQ about 255.255.255.255 broadcast and invalid firewall
rules, but I don't have any firewall rules and I'm not changing network
config files when switching to isc-dhcp-server (which I use as a benchmark)

Kind regards,
Kamil


>
>
> Groeten
> Geert Stappers
> --
> Silence is hard to parse
>
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