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On 20/05/2022 19:19,
Simon Kelley <<a href="mailto:simon@thekelleys.org.uk">simon@thekelleys.org.uk</a>>
wrote:
<div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><br>
I have a theory:<br>
<br>
In the logs, it takes between 7 and 9 seconds after carrier detect on <br>
eth0 (I guess that's when you plug the RTMU86 in?) before eth0 is <br>
allocated IP address 192.168.6.1. Until the address is allocated, <br>
dnsmasq will ignore DHCP requests and log<br>
<br>
"DHCP packet received on eth0 which has no address"<br>
<br>
If the RTMU86 send a DHCP discover faster than 7 seconds and doesn't <br>
retry in a reasonable time, that could explain the problem.<br>
<br>
ISC dhcpd may not need the local interface to be configured with an IP <br>
address, which would explain the different behaviour.<br>
<br>
<br>
The packet capture below shows just one DHCPDISCOVER being sent from<br>
0.0.0.0.bootpc > 255.255.255.255.bootps<br>
<br>
and it's before the IP 192.168.6.1 > <a href="http://igmp.mcast.net" rel="noreferrer" target="_blank">igmp.mcast.net</a> which markswhen <br>
eth0 gets an IP address.<br>
<br>
If you repeat the same test and leave the capture running for a few <br>
minutes, do you see any more 0.0.0.0.bootpc > 255.255.255.255.bootps <br>
packets, and if you do, do they get a reply?<br>
<br>
If I'm right, the solution may be to configure eth0 with a statis IP <br>
address, so it doesn't have to wait for dhcpcd to go through a lengthy <br>
process to give it an IP address every time the cable gets plugged in.<br>
<br></blockquote><div> </div><div>
<div><div>
Dear Simon, <br></div><div><br></div><div>1) I've just sent my reply to
Geert where I included my full logs with exact timestamps and my comments. Please have a look: <a href="https://www.mail-archive.com/dnsmasq-discuss@lists.thekelleys.org.uk/msg16249.html">https://www.mail-archive.com/dnsmasq-discuss@lists.thekelleys.org.uk/msg16249.html</a></div><div>2) Because
I'm switching between two devices and the address for "Device X" is
being assigned every time - I think that it's not the case of "time".</div><div>3) Also I've left RTMU86 for a little bit longer and as you can see it retries several times.</div>4) eth0 has static IP configured for all this time. In /etc/dhcpcd.conf I have:</div><div>> interface eth0<br>> static ip_address=<a href="http://192.168.6.1/24" target="_blank">192.168.6.1/24</a> </div><div><br></div><div>Kind regards,</div><div>Kamil</div>
</div><div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
<br>
Simon.<br>
<br>
<br>
On 15/05/2022 15:40, Kamil via Dnsmasq-discuss wrote:<br>
> <br>
> On Sun, May 15, 2022 at 01:10:40AM +0200, Kamil via Dnsmasq-discuss<br>
> wrote:<br>
> > On Sat, May 14, 2022 at 11:27:34AM +0200, Geert Stappers via<br>
> Dnsmasq-discuss wrote:<br>
> > > On Sat, May 14, 2022 at 02:53:51AM +0200, Kamil via<br>
> Dnsmasq-discuss wrote:<br>
> ...<br>
> > > > 1. I plug one device - it works.<br>
> > > > 2. I unplug it and plug the RTMU86 - doesn't work.<br>
> > > > 3. I Unplug RTMU86 and plug any other device - it works.<br>
> > > ><br>
> ...<br>
> > > Be yourself, accept yourself. Full focus on the challenge that<br>
> you are<br>
> > > facing.<br>
> ><br>
> > Sure<br>
> ><br>
> <br>
> What proof is available of<br>
> the RTMU86 sending DHCP packages<br>
> when pluging the ethercable back in?<br>
> <br>
> <br>
> RTMU86 has a led indicator that is lid when the address has been <br>
> assigned to it.<br>
> 1. If I plug RTMU86 to the home router - the led is on, I can find its <br>
> IP in the router's lease list and I can ping this IP<br>
> 2. If I plug RTMU86 to the RPi with isc-dhcp-server configured - the led <br>
> is on, I can find its IP in the isc-dhcp-server's lease list and I can <br>
> ping this IP<br>
> 3. If I plug RTMU86 to the RPi with Dnsmasq configured - I can use <br>
> tcpdump which gives me this output (I changed MAC addresses):<br>
> > 16:17:31.125779 IP 0.0.0.0.bootpc > 255.255.255.255.bootps: <br>
> BOOTP/DHCP, Request from fa:XX:XX:XX:XX:1c (oui Unknown), length 300<br>
> So I presume that RTMU86 indeed sends DHCP packages, but the led is off <br>
> and I can not find it in the Dnsmasq lease list.<br>
> <br>
> Full tcpdump log (with changed MAC addresses) below:<br>
> > 16:17:28.175124 IP6 :: > ff02::16: HBH ICMP6, multicast listener <br>
> report v2, 2 group record(s), length 48<br>
> > 16:17:28.187120 IP6 :: > ff02::16: HBH ICMP6, multicast listener <br>
> report v2, 4 group record(s), length 88<br>
> > 16:17:28.199412 ARP, Request who-has 192.168.6.1 tell 0.0.0.0, length 28<br>
> > 16:17:28.235076 IP6 :: > ff02::16: HBH ICMP6, multicast listener <br>
> report v2, 4 group record(s), length 88<br>
> > 16:17:28.483118 IP6 :: > ff02::1:fffb:fe9: ICMP6, neighbor <br>
> solicitation, who has fe80::XX:XX:XX:fe9, length 32<br>
> > 16:17:29.507285 IP6 fe80::XX:XX:XX:fe9 > ff02::16: HBH ICMP6, <br>
> multicast listener report v2, 5 group record(s), length 108<br>
> > 16:17:29.507966 IP6 fe80::XX:XX:XX:fe9 > ip6-allrouters: ICMP6, <br>
> router solicitation, length 16<br>
> > 16:17:29.519049 IP6 fe80::XX:XX:XX:fe9 > ff02::16: HBH ICMP6, <br>
> multicast listener report v2, 1 group record(s), length 28<br>
> > 16:17:29.891065 IP6 fe80::XX:XX:XX:fe9 > ff02::16: HBH ICMP6, <br>
> multicast listener report v2, 5 group record(s), length 108<br>
> > 16:17:30.019064 IP6 fe80::XX:XX:XX:fe9 > ff02::16: HBH ICMP6, <br>
> multicast listener report v2, 1 group record(s), length 28<br>
> > 16:17:30.077265 IP6 fe80::XX:XX:XX:fe9.mdns > ff02::fb.mdns: 0*- [0q] <br>
> 2/0/0 (Cache flush) PTR myhost.local., (Cache flush) AAAA <br>
> fe80::XX:XX:XX:fe9 (139)<br>
> > 16:17:30.151935 ARP, Request who-has 192.168.6.1 tell 0.0.0.0, length 28<br>
> > 16:17:31.125779 IP 0.0.0.0.bootpc > 255.255.255.255.bootps: <br>
> BOOTP/DHCP, Request from fa:XX:XX:XX:XX:1c (oui Unknown), length 300<br>
> > 16:17:31.728625 ARP, Request who-has 192.168.6.1 tell 0.0.0.0, length 28<br>
> > 16:17:32.152301 IP6 fe80::XX:XX:XX:fe9.mdns > ff02::fb.mdns: 0*- [0q] <br>
> 2/0/0 (Cache flush) PTR myhost.local., (Cache flush) AAAA <br>
> fe80::XX:XX:XX:fe9 (139)<br>
> > 16:17:33.510623 IP6 fe80::XX:XX:XX:fe9 > ip6-allrouters: ICMP6, <br>
> router solicitation, length 16<br>
> > 16:17:33.730051 ARP, Request who-has 192.168.6.1 tell 192.168.6.1, <br>
> length 28<br>
> > 16:17:33.739141 IP 192.168.6.1 > <a href="http://igmp.mcast.net" rel="noreferrer" target="_blank">igmp.mcast.net</a> <br>
> <<a href="http://igmp.mcast.net" rel="noreferrer" target="_blank">http://igmp.mcast.net</a>>: igmp v3 report, 1 group record(s)<br>
> <br>
> PS. I've read in FAQ about 255.255.255.255 broadcast and invalid <br>
> firewall rules, but I don't have any firewall rules and I'm not changing <br>
> network config files when switching to isc-dhcp-server (which I use as a <br>
> benchmark)<br>
> <br>
> Kind regards,<br>
> Kamil<br>
> <br>
> <br>
> <br>
> Groeten<br>
> Geert Stappers<br>
> -- <br>
> Silence is hard to parse<br>
> <br>
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</blockquote></div></div>