<div dir="ltr"><blockquote style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex" class="gmail_quote"><br style="color:rgb(34,34,34);font-family:Arial,Helvetica,sans-serif;font-size:small;white-space:normal"><span style="color:rgb(34,34,34);font-family:Arial,Helvetica,sans-serif;font-size:small;white-space:normal">Tell more about the set up in use.</span><br style="color:rgb(34,34,34);font-family:Arial,Helvetica,sans-serif;font-size:small;white-space:normal"><span style="color:rgb(34,34,34);font-family:Arial,Helvetica,sans-serif;font-size:small;white-space:normal">My hope is that it provides some clue why `tcpdump` can see DHCP network<br></span><span style="color:rgb(34,34,34);font-family:Arial,Helvetica,sans-serif;font-size:small;white-space:normal">traffic that `dnsmasq` should seen also.</span></blockquote><pre style="font-family:courier,"courier new",monospace;font-size:14px;white-space:pre-wrap;margin-top:0px;margin-bottom:0px;color:rgb(0,0,0)"><span style="color:rgb(34,34,34);font-family:Arial,Helvetica,sans-serif;font-size:small;white-space:normal"><br></span></pre><pre style="font-family:courier,"courier new",monospace;font-size:14px;white-space:pre-wrap;margin-top:0px;margin-bottom:0px;color:rgb(0,0,0)">I'm running a very odd environment in that I'm using 2 usermodelinux
virtual machines connected via a virtual hub. I've got such a simple setup
because originally I had a much larger configuration and wanted to test it
wasn't something messed up in routing and such.</pre><pre style="font-family:courier,"courier new",monospace;font-size:14px;white-space:pre-wrap;margin-top:0px;margin-bottom:0px;color:rgb(0,0,0)">Just wanted to add that dnsmasq 2.62 with a much older Linux kernel (3.2
from memory?) worked on this sort of setup perfectly fine, so it seems
thats either the kernel update or a newer version of dnsmasq has broken
something along the way.
Thanks,
Josh
P.s never used a mailing list before so apologies for the wrong formatting!</pre></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Tue, 14 Apr 2020 at 20:19, Geert Stappers <<a href="mailto:stappers@stappers.nl">stappers@stappers.nl</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">On Tue, Apr 14, 2020 at 06:51:25PM +0100, Josh H wrote:<br>
> Hi there,<br>
> <br>
> I'm receiving no DHCPOffer back from my DHCPDiscover. However, I can<br>
> tcpdump the machine running dnsmasq and it is receiving the DHCPOffer<br>
> packets.<br>
<br>
Acknowledge<br>
<br>
<br>
> Here's my very very simple dnsmasq.conf<br>
> # To disable dnsmasq's DNS server functionality.<br>
> port=0<br>
> <br>
> # To enable dnsmasq's DHCP server functionality.<br>
> dhcp-range=192.168.1.3,192.168.1.8,255.255.255.240,12h<br>
> <br>
> # Set gateway as Router. Following two lines are identical.<br>
> #dhcp-option=option:router,192.168.0.1<br>
> dhcp-option=3,192.168.0.1<br>
> <br>
> # Set DNS server as Router.<br>
> dhcp-option=6,192.168.0.1<br>
> <br>
> # Logging.<br>
> log-facility=/var/log/dnsmasq.log # logfile path.<br>
> log-async<br>
> log-queries # log queries.<br>
> log-dhcp # log dhcp related messages.<br>
<br>
Acknowledge on `log DHCP`<br>
<br>
<br>
> <br>
> Here's the contents of /var/log/dnsmasq.log after running dhclient on a<br>
> machine connected to the subnet:<br>
> Apr 14 18:36:57 dnsmasq[1702]: started, version 2.80 DNS disabled<br>
> Apr 14 18:36:57 dnsmasq[1702]: compile time options: IPv6 GNU-getopt DBus i18n IDN DHCP DHCPv6 no-Lua TFTP conntrack ipset auth DNSSEC loop-detect inotify dumpfile<br>
> Apr 14 18:36:57 dnsmasq-dhcp[1702]: DHCP, IP range 192.168.1.3 -- 192.168.1.8, lease time 12h<br>
<br>
Missing DHCP related entries ...<br>
<br>
<br>
> I can see the service running with netstat -anp4:<br>
> Active Internet connections (servers and established)<br>
> Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name<br>
> udp 0 0 <a href="http://0.0.0.0:67" rel="noreferrer" target="_blank">0.0.0.0:67</a> 0.0.0.0:* 1702/dnsmasq<br>
> udp 0 0 <a href="http://0.0.0.0:1701" rel="noreferrer" target="_blank">0.0.0.0:1701</a> 0.0.0.0:* 1607/xl2tpd<br>
> <br>
> There are no firewalls setup anywhere on my network for the moment. I have<br>
> been able to get isc-dhcp-server to successfully allocate DHCP requests<br>
> just fine however, so I don't think it's anything broken with DHCP in<br>
> general. I'm running Linux kernel 5.6.2 and using dnsmasq from Debian<br>
> Bullseye.<br>
> <br>
> Hopefully someone can work out my issue!<br>
<br>
You already have met the best someone ;-)<br>
<br>
Tell more about the set up in use.<br>
<br>
My hope is that it provides some clue why `tcpdump` can see DHCP network<br>
traffic that `dnsmasq` should seen also.<br>
<br>
<br>
> Thank you very much!<br>
<br>
Thank you for reporting in an interresting problem.<br>
<br>
<br>
<br>
Regards<br>
Geert Stappers<br>
-- <br>
Silence is hard to parse<br>
<br>
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</blockquote></div>