[Dnsmasq-discuss] Cannot obtain IP address from dnsmasq

Discussion:

Matwey V. Kornilov

2016-06-24 09:10:53 UTC

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?

Albert ARIBAUD

2016-06-24 16:19:38 UTC

Permalink

Hi Matwey,

Le Fri, 24 Jun 2016 12:10:53 +0300

Post by Matwey V. Kornilov
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
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?

The above is a tcpdump log. What does dnsmaq itself log? Think of
adding the log-dhcp option to the dnsmasq config file beforehand.

Amicalement,

--
Albert.

Matwey V. Kornilov

2016-06-24 16:30:04 UTC

Permalink

Post by Albert ARIBAUD
Hi Matwey,
Le Fri, 24 Jun 2016 12:10:53 +0300

The above is a tcpdump log. What does dnsmaq itself log? Think of
adding the log-dhcp option to the dnsmasq config file beforehand.

Nothing about 192.168.1.1 in log-dhcp, unfortunately.

Post by Albert ARIBAUD
Amicalement,
--
Albert.

--
With best regards,
Matwey V. Kornilov
http://blog.matwey.name
xmpp://***@jabber.ru

Albert ARIBAUD

2016-06-24 20:21:23 UTC

Permalink

Hi Matwey,

Le Fri, 24 Jun 2016 19:30:04 +0300

Post by Matwey V. Kornilov

Post by Albert ARIBAUD
Hi Matwey,
Le Fri, 24 Jun 2016 12:10:53 +0300

Post by Matwey V. Kornilov
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
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,
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?

The above is a tcpdump log. What does dnsmaq itself log? Think of
adding the log-dhcp option to the dnsmasq config file beforehand.

Nothing about 192.168.1.1 in log-dhcp, unfortunately.

Not a dnsmasq issue, then: if the request from 192.168.1.1 never
reaches dnsmasq, it's either dnsmasq not listening on the right
interface or a network issue. Since requests from others on the
same physical network segment are seen, dnsmasq is listening on the
right interface. Therefore, it is a network issue.

Amicalement,

--
Albert.

Dan Sneddon

2016-06-24 19:55:29 UTC

Permalink

Post by Matwey V. Kornilov
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
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?
_______________________________________________
Dnsmasq-discuss mailing list
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
***@redhat.com | redhat.com/openstack
650.254.4025 | dsneddon:irc @dxs:twitter