[Dnsmasq-discuss] Restrict DHCP providing default gateway to *one* host on one network

Will Dennis (Live.com) willarddennis at live.com
Tue Apr 23 15:33:23 BST 2013


Hi, Simon

OK, did add the log-dhcp option; here are the active stanzas in my
dnsmasq.conf as of now:

# grep -v ^# /etc/dnsmasq.conf | grep -v ^$
interface=vl10-ovsbr0
interface=vl20-ovsbr0
bind-interfaces
dhcp-range=vl10-ovsbr0,192.168.10.50,192.168.10.150,4h
dhcp-range=vl20-ovsbr0,192.168.20.50,192.168.20.150,4h
dhcp-host=52:54:00:d5:ee:4d,id:*,192.168.10.1
dhcp-mac=set:wanem-20,52:54:00:45:8c:6a
dhcp-option=vl10-ovsbr0,3,192.168.10.254
dhcp-option=tag:vl20-ovsbr0,tag:!wanem-20,3,192.168.20.254
log-dhcp

Here is the output of log-dhcp from my syslog file as regards the WANem VM
requesting DHCP for its two NICs:

http://pastebin.com/nuWKa67q

On line 67 and 86 (not sure why two DHCPDISCOVER's coming from the VM?) I
see dnsmasq providing a default gateway (router) to the net-20 NIC as a part
of the DHCPOFFER...

Thanks again for your assistance with troubleshooting this!

Will

-----Original Message-----
From: Simon Kelley [mailto:simon at thekelleys.org.uk] 
Sent: Tuesday, April 23, 2013 4:51 AM
To: Will Dennis (Live.com)
Cc: dnsmasq-discuss at lists.thekelleys.org.uk
Subject: Re: [Dnsmasq-discuss] Restrict DHCP providing default gateway to
*one* host on one network

<snip>

Add

log-dhcp

to your configuration. Amongst other useful information, that will tell you
exactly what options are being sent, and the tags which are set during any
DHCP transaction. Both of these will help trace the problem.


Cheers,

Simon.

<snip>




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