[Dnsmasq-discuss] Cannot obtain IP address from dnsmasq

[Dan Sneddon]

On 06/24/2016 02:10 AM, Matwey V. Kornilov wrote:
> Hello,
> 
> I am running dnsmasq-2.71 and experiencing the following issue.
> 
> I have network interface eth3 with 10.3.0.1/24 address assigned to it.
> I want dnsmasq instance to supply everyone on eth3 L2-segment with IP
> address from 10.3.0.1/24 subnet. I don't want DHCP be running on other
> interfaces where it can interfere others.
> 
> The issue is the following, HP commutator can not obtain address.
> 
> 12:03:01.609174 IP 192.168.1.1.68 > 255.255.255.255.67: BOOTP/DHCP,
> Request from 40:a8:f0:6f:64:40, length 256
> 12:03:23.952477 IP 192.168.1.1.68 > 255.255.255.255.67: BOOTP/DHCP,
> Request from 40:a8:f0:6f:64:40, length 256
> 
> At the same time, other devises obtain address successfully:
> 
> 12:03:45.311101 IP 0.0.0.0.68 > 255.255.255.255.67: BOOTP/DHCP, Request
> from 44:aa:e8:00:0c:4e, length 249
> 12:03:45.313634 IP 10.3.0.1.67 > 255.255.255.255.68: BOOTP/DHCP, Reply,
> length 300
> 12:03:45.340273 IP 0.0.0.0.68 > 255.255.255.255.67: BOOTP/DHCP, Request
> from 44:aa:e8:00:0c:4e, length 256
> 12:03:45.371271 IP 10.3.0.1.67 > 255.255.255.255.68: BOOTP/DHCP, Reply,
> length 300
> 12:03:45.395392 IP 10.3.0.33.1025 > 239.255.255.250.1900: UDP, length 320
> 12:03:46.884261 IP 0.0.0.0.68 > 255.255.255.255.67: BOOTP/DHCP, Request
> from 44:aa:e8:00:0c:46, length 249
> 12:03:46.885707 IP 10.3.0.1.67 > 255.255.255.255.68: BOOTP/DHCP, Reply,
> length 300
> 12:03:46.911271 IP 0.0.0.0.68 > 255.255.255.255.67: BOOTP/DHCP, Request
> from 44:aa:e8:00:0c:46, length 256
> 12:03:46.945596 IP 10.3.0.1.67 > 255.255.255.255.68: BOOTP/DHCP, Reply,
> length 300
> 12:03:46.968662 IP 10.3.0.32.1025 > 239.255.255.250.1900: UDP, length 320
> 12:03:50.390213 IP 10.3.0.33.1025 > 239.255.255.250.1900: UDP, length 320
> 
> I suppose, that the issue here is that HP's source address is
> 192.168.1.1, how could I configure dnsmasq to overcome this issue?
> 
> 
> _______________________________________________
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> Dnsmasq-discuss at lists.thekelleys.org.uk
> http://lists.thekelleys.org.uk/mailman/listinfo/dnsmasq-discuss

I'm going to take a wild guess at your problem, based on the limited
data available.

If the DHCP request is coming from 192.168.1.1, that sounds like a
configuration issue on the HP commutator (whatever that is). Is the HP
configured to use a particular IP with DHCP (for the subnet mask,
gateway, etc.)? If so, you need to reconfigure the HP, because it won't
be able to obtain a reservation for it's preferred IP because it's on
the wrong subnet. You can either configure the HP to use a static IP on
the correct subnet, or modify it to obtain an IP address dynamically.

-- 
Dan Sneddon         |  Principal OpenStack Engineer
dsneddon at redhat.com |  redhat.com/openstack
650.254.4025        |  dsneddon:irc   @dxs:twitter