[Dnsmasq-discuss] No DHCP on eth1

Michael Rack michael.rack at rsm-freilassing.de
Wed Nov 17 14:45:41 GMT 2010


Wow, that is really freaky what you are doing ;-)

You can not AND you should not assign IP-Adresses to an bridged Interface!
Remove all IP-Adresses from eth1. Your Interface eth1 should only have 
0.0.0.0 assigned and link-state to be up.

DNSMASQ have to listen on virbr0 not on eth1



Liebe Grüße aus Freilassing,

Michael Rack
RSM Freilassing
-- 
RSM Freilassing                 Tel.: +49 8654 607110
Nocksteinstr. 13                Fax.: +49 8654 670438
D-83395 Freilassing            www.rsm-freilassing.de


Am 17.11.2010 11:43, schrieb Eldon Ziegler:
> We are downsizing an app that runs on multiple servers onto a single
> server but are not getting DHCP responses from dnsmasq on eth1. It works
> correctly when dnsmasq is run on a separate server.
> dnsmasq-2.45-1.1.el5_3 from Red Hat is running.
>
> Virtual machines are started dynamically (using QEMU-KVM) and are
> connected to tap0 and tap1 on bridge virbr0. All MAC to IP address
> assignments are via /etc/ethers.
>
> sudo brctl show
> bridge name	bridge id		STP enabled	interfaces
> virbr0		8000.00259010282a	no		tap1
> 							tap0
> 							eth1
>
> tcpdump shows the DHCP requests on eth1.
>
> listening on eth1, link-type EN10MB (Ethernet), capture size 96 bytes
> 05:19:42.338702 IP 0.0.0.0.68>  255.255.255.255.67: BOOTP/DHCP, Request from 00:50:56:01:00:01, length: 300
> 05:19:43.150538 IP 0.0.0.0.68>  255.255.255.255.67: BOOTP/DHCP, Request from 00:50:56:01:01:01, length: 300
> 05:19:47.149363 IP 0.0.0.0.68>  255.255.255.255.67: BOOTP/DHCP, Request from 00:50:56:01:01:01, length: 300
> 05:19:51.150423 IP 0.0.0.0.68>  255.255.255.255.67: BOOTP/DHCP, Request from 00:50:56:01:01:01, length: 300
> 05:19:58.152492 IP 0.0.0.0.68>  255.255.255.255.67: BOOTP/DHCP, Request from 00:50:56:01:01:01, length: 300
> 05:19:58.336652 IP 0.0.0.0.68>  255.255.255.255.67: BOOTP/DHCP, Request from 00:50:56:01:00:01, length: 300
> 05:20:12.189338 IP 0.0.0.0.68>  255.255.255.255.67: BOOTP/DHCP, Request from 00:50:56:01:01:01, length: 300
>
> The log shows no indication that dnsmasq saw the messages.
>
> Nov 17 05:19:33 allin1 kernel: virbr0: topology change detected, propagating
> Nov 17 05:19:33 allin1 kernel: virbr0: port 2(tap0) entering forwarding state
> Nov 17 05:19:34 allin1 kernel: virbr0: topology change detected, propagating
> Nov 17 05:19:34 allin1 kernel: virbr0: port 3(tap1) entering forwarding state
> Nov 17 05:23:02 allin1 dnsmasq[8997]: exiting on receipt of SIGTERM
>
> Extracts from dnsmasq.conf
>
> #interface=eth0
> interface=eth1
> #interface=eth2
> #interface=eth3
>
> no-dhcp-interface=eth0
> no-dhcp-interface=eth2
>
> dhcp-range=10.0.0.230,static,255.255.0.0,10m
> dhcp-range=10.1.0.230,static,255.255.0.0,10m
> dhcp-range=10.2.0.230,static,255.255.0.0,10m
> dhcp-range=10.3.0.230,static,255.255.0.0,10m
> dhcp-range=10.4.0.230,static,255.255.0.0,10m
> dhcp-range=10.5.0.230,static,255.255.0.0,10m
> dhcp-range=10.6.0.230,static,255.255.0.0,10m
> dhcp-range=10.7.0.230,static,255.255.0.0,10m
> dhcp-range=10.8.0.230,static,255.255.0.0,10m
> dhcp-range=10.9.0.230,static,255.255.0.0,10m
> dhcp-range=10.10.0.230,static,255.255.0.0,10m
>
> cat /etc/ethers
> 00:50:56:01:00:01 10.0.1.0
> 00:50:56:01:01:01 10.0.1.1
>
> eth1      Link encap:Ethernet  HWaddr 00:25:90:10:28:2A
>            inet addr:10.0.0.1  Bcast:10.0.255.255  Mask:255.255.0.0
>            inet6 addr: fe80::225:90ff:fe10:282a/64 Scope:Link
>            UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
>            RX packets:117 errors:0 dropped:0 overruns:0 frame:0
>            TX packets:427 errors:0 dropped:0 overruns:0 carrier:0
>            collisions:0 txqueuelen:1000
>            RX bytes:17430 (17.0 KiB)  TX bytes:76864 (75.0 KiB)
>            Memory:d8020000-d8040000
>
> eth1:101  Link encap:Ethernet  HWaddr 00:25:90:10:28:2A
>            inet addr:10.0.0.101  Bcast:10.0.255.255  Mask:255.255.0.0
>            UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
>            Memory:d8020000-d8040000
>
> tap0      Link encap:Ethernet  HWaddr 06:4E:13:A2:24:EC
>            inet6 addr: fe80::44e:13ff:fea2:24ec/64 Scope:Link
>            UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
>            RX packets:10 errors:0 dropped:0 overruns:0 frame:0
>            TX packets:6 errors:0 dropped:0 overruns:0 carrier:0
>            collisions:0 txqueuelen:500
>            RX bytes:1836 (1.7 KiB)  TX bytes:1800 (1.7 KiB)
>
> tap1      Link encap:Ethernet  HWaddr 2A:9C:E6:EF:BD:B0
>            inet6 addr: fe80::289c:e6ff:feef:bdb0/64 Scope:Link
>            UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
>            RX packets:6 errors:0 dropped:0 overruns:0 frame:0
>            TX packets:5 errors:0 dropped:0 overruns:0 carrier:0
>            collisions:0 txqueuelen:500
>            RX bytes:1800 (1.7 KiB)  TX bytes:1186 (1.1 KiB)
>
> virbr0    Link encap:Ethernet  HWaddr 00:25:90:10:28:2A
>            inet addr:10.0.0.101  Bcast:10.0.255.255  Mask:255.255.0.0
>            inet6 addr: fe80::225:90ff:fe10:282a/64 Scope:Link
>            UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
>            RX packets:453 errors:0 dropped:0 overruns:0 frame:0
>            TX packets:18 errors:0 dropped:0 overruns:0 carrier:0
>            collisions:0 txqueuelen:0
>            RX bytes:88453 (86.3 KiB)  TX bytes:3737 (3.6 KiB)
>
> sudo netstat -nlp | grep dnsmasq
> tcp        0      0 0.0.0.0:53                  0.0.0.0:*                   LISTEN      9254/dnsmasq
> tcp        0      0 :::53                       :::*                        LISTEN      9254/dnsmasq
> udp        0      0 0.0.0.0:53                  0.0.0.0:*                               9254/dnsmasq
> udp        0      0 0.0.0.0:67                  0.0.0.0:*                               9254/dnsmasq
> udp        0      0 :::53                       :::*                                    9254/dnsmasq
>
> Connection to the LAN is on eth2.
>
> Note, a cross over cable is used between eth0 and eth1 to get the NICs
> in "RUNNING" mode. The DHCP request messages did not appear on eth1
> until this cable was installed.
>
> Any suggestions will be appreciated.
>
> Eldon
>
>
>
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