[Dnsmasq-discuss] Failing to get DHCP responses on OpenBSD

Geert Stappers stappers at stappers.nl
Sat Dec 7 20:44:08 GMT 2019


On Sat, Dec 07, 2019 at 09:38:07PM +0200, dnsmasq at mailfri.com wrote:
> Hi,
> 
> I am trying to run the dnsmasq 2.80 port on my OpenBSD home router and
> am failing miserably at soliciting any response for DHCP requests. I am
> reasonably sure that my firewall and routing settings are good because
> the dhcpd that comes with OpenBSD works just fine (and I can see DHCP
> requests on interface em2 with tcpdump).
> 
> I tried all sorts of combinations of bindings, interface, dhcp-range,
> etc. but I keep getting output like this and nothing else:
> 
> $ dnsmasq -d -q --log-dhcp --interface=em1 --interface=em2 --interface=em3 --dhcp-range=172.16.10.32,172.16.10.127 --dhcp-range=172.16.11.32,172.16.11.127 --dhcp-range=172.16.12.32,172.16.12.127 --dhcp-authoritative
> dnsmasq: started, version 2.80 cachesize 150
> dnsmasq: compile time options: IPv6 GNU-getopt no-DBus no-i18n no-IDN DHCP DHCPv6 no-Lua TFTP no-conntrack ipset auth no-DNSSEC loop-detect no-inotify dumpfile
> dnsmasq-dhcp: DHCP, IP range 172.16.12.32 -- 172.16.12.127, lease time 1h
> dnsmasq-dhcp: DHCP, IP range 172.16.11.32 -- 172.16.11.127, lease time 1h
> dnsmasq-dhcp: DHCP, IP range 172.16.10.32 -- 172.16.10.127, lease time 1h
> dnsmasq: reading /etc/resolv.conf
> dnsmasq: using nameserver 43.23.18.136#53
> dnsmasq: using nameserver 43.23.18.135#53
> dnsmasq: read /etc/hosts - 2 addresses
> 
> 
> fstat tells me that dnsmasq is bound to *:67 (i.e. port 67 on all
> interfaces) as it should. Any ideas what else I could try still? And
> is there some sort of debug setting that would allow me to see if
> dnsmasq sees the DHCP requests and what it decides to do with them?

That is '--log-dhcp', you have it already active.

But you are stuck. Here some "last resort actions"

A. stop dnsmasq and check again what fstat says about port 67
B. try only 1 interface  (add the others I/F when 1 works)


> Here is my network interface configuration:
> 
> $ ifconfig
> lo0: flags=8049<UP,LOOPBACK,RUNNING,MULTICAST> mtu 32768
>         index 6 priority 0 llprio 3
>         groups: lo
>         inet6 ::1 prefixlen 128
>         inet6 fe80::1%lo0 prefixlen 64 scopeid 0x6
>         inet 127.0.0.1 netmask 0xff000000
> em0: flags=a08843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST,AUTOCONF6,AUTOCONF4> mtu 1500
>         lladdr 00:0d:1a:e3:81:62
>         description: WAN
>         index 1 priority 0 llprio 3
>         groups: egress
>         media: Ethernet autoselect (1000baseT full-duplex,rxpause,txpause)
>         status: active
>         inet 182.227.21.34 netmask 0xffffe000 broadcast 182.227.21.255

FWIW:
  netmask and broadcast don't match. Make the broadcast 182.227.31.255
  to match the netmask


>         inet6 fe80::20e:c4ff:fed2:829d%em0 prefixlen 64 scopeid 0x1
> em1: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
>         lladdr 00:0d:1a:e3:81:63
>         description: WIFI
>         index 2 priority 0 llprio 3
>         media: Ethernet autoselect (none)
>         status: no carrier
>         inet 172.16.12.1 netmask 0xffffff00 broadcast 172.16.12.255
> em2: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
>         lladdr 00:0d:1a:e3:81:64
>         description: Intra
>         index 3 priority 0 llprio 3
>         media: Ethernet autoselect (1000baseT full-duplex,master,rxpause,txpause)
>         status: active
>         inet 172.16.10.1 netmask 0xffffff00 broadcast 172.16.10.255
> em3: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
>         lladdr 00:0d:1a:e3:81:65
>         description: DMZ
>         index 4 priority 0 llprio 3
>         media: Ethernet autoselect (none)
>         status: no carrier
>         inet 172.16.11.1 netmask 0xffffff00 broadcast 172.16.11.255
> enc0: flags=0<>
>         index 5 priority 0 llprio 3
>         groups: enc
>         status: active
> pflog0: flags=141<UP,RUNNING,PROMISC> mtu 33136
>         index 7 priority 0 llprio 3
>         groups: pflog
> 


Groeten
Geert Stappers
-- 
Leven en laten leven



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