[Dnsmasq-discuss] Single interface, multiple subnets...

[Scott]

Hmmm.  Well turning off dnsmasq & throwing up a quick windows DHCP server
seems to work for both subnets in terms of distributing the IP's.  =\

I did just test again by removing the 2nd network segment.  I've placed all
three machines on the same physical network.  I have the 2 DHCP ranges
configured in dnsmasq, and I have 2 reservations made via MAC address.  The
reservation for the 192.168.1.128/25 range hands out, the reservation for
the 192.168.1.0/25 gives the " no address range available for DHCP request
via eth0" error.  So now I'm able to repro on the same physical segment,
simply due to the fact that the IP reservation I've made is in a different
subnet than the eth0 IP address.  If I change eth0 on the DHCP server to an
IP in the 192.168.1.0/25 range, then suddenly the 192.168.1.0/25 DHCP
reservation works, and the 192.168.1.128/25 reservation that was working
previously gives the " no address range available for DHCP request via eth0"
error.

So to me, this definitely has something to do with the dnsmasq configuration
as it pertains to serving reservations outside of it's subnet.

Regards,
Scott Jarboe


-----Original Message-----
From: Simon Kelley [mailto:simon at thekelleys.org.uk] 
Sent: Monday, September 27, 2010 12:34 PM
To: Scott
Cc: dnsmasq-discuss at lists.thekelleys.org.uk
Subject: Re: [Dnsmasq-discuss] Single interface, multiple subnets...

Scott wrote:
> The DHCP relay is the router itself, ip helper is configured which
forwards
> the packets.  Again, the dhcp requests are being received by the dhcp
> server, it simply won't serve out the address.  One thing I did forget to
> mention is that I have mac reservations for each server.
> 
> The issue however, is not in the routing.  If I take server1 and modify
the
> reservation to an IP in the dhcp server's subnet (192.168.1.128/25), the
> dhcp server gives it an address.  It's only when I tell the dhcp server to
> give it an IP in the 192.168.1.0/25 subnet that it gives the error:  "Sep
24
> 12:45:47 server1 dnsmasq[2640]: no address range available for DHCP
request
> via eth0".
> 

Something is wrong somewhere: if the ip helper was doing the correct 
thing and setting the giaddr field in DHCP packet then the message would 
say "....DHCP request via w.x.y.z" and not "via eth0". Can you check 
that your DHCP relay is set up properly?


Simon.