[Dnsmasq-discuss] dnsmaq responds with DHCPNACK

Budai Laszlo laszlo.budai at gmail.com
Mon Jun 18 10:33:13 BST 2018


Hi Simon,

Thank you for the answer.
This is the command line for the dnsmasq process:

dnsmasq --no-hosts --no-resolv --strict-order --bind-interfaces --interface=tap347066a3-42 --except-interface=lo --pid-file=/var/lib/neutron/dhcp/af5d4690-46b6-4ad3-b0ee-6f02e2d1a8e2/pid --dhcp-hostsfile=/var/lib/neutron/dhcp/af5d4690-46b6-4ad3-b0ee-6f02e2d1a8e2/host --addn-hosts=/var/lib/neutron/dhcp/af5d4690-46b6-4ad3-b0ee-6f02e2d1a8e2/addn_hosts --dhcp-optsfile=/var/lib/neutron/dhcp/af5d4690-46b6-4ad3-b0ee-6f02e2d1a8e2/opts --dhcp-leasefile=/var/lib/neutron/dhcp/af5d4690-46b6-4ad3-b0ee-6f02e2d1a8e2/leases --dhcp-range=set:tag0,192.168.1.0,static,86400s --dhcp-lease-max=256 --conf-file= --domain=openstacklocal

so there is no such setting on the command line, and no config file is set . So the value should be a default one (which I guess that it is not authoritative.

Kind regards,
Laszlo

On 16.06.2018 00:17, Simon Kelley wrote:
> Do you have dhcp-authoritative set in the dnsmasq configuration?
> 
> 
> Simon.
> 
> 
> 
> On 14/06/18 14:02, Budai Laszlo wrote:
>> Hello,
>>
>> we have an openstack install that uses dnsmasq for dhcp functionality.
>> we have 2 ndsmasq processes running for each network (on different
>> openstack network nodes).
>>  From time to time I can see DHCPNACK sent by one of the servers when a
>> client is trying to renew its lease.
>>
>> On the client log I have the following:
>>
>> Jun  7 09:34:25 hhr-prd-be1 dhclient: message repeated 2580 times: [
>> DHCPREQUEST of 192.168.1.32 on eth0 to 192.168.1.1 port 67
>> (xid=0x196ca4cf)]
>> Jun  7 09:34:25 hhr-prd-be1 dhclient: DHCPACK of 192.168.1.32 from
>> 192.168.1.1
>> Jun  7 09:34:25 hhr-prd-be1 dhclient: bound to 192.168.1.32 -- renewal
>> in 36110 seconds.
>> Jun  7 19:36:15 hhr-prd-be1 dhclient: DHCPREQUEST of 192.168.1.32 on
>> eth0 to 192.168.1.1 port 67 (xid=0x196ca4cf)
>> Jun  7 19:36:15 hhr-prd-be1 dhclient: DHCPNAK from 192.168.1.1
>> (xid=0xcfa46c19)
>> Jun  7 19:36:15 hhr-prd-be1 dhclient: DHCPDISCOVER on eth0 to
>> 255.255.255.255 port 67 interval 3 (xid=0x1a8d6d00)
>> Jun  7 19:36:15 hhr-prd-be1 dhclient: DHCPREQUEST of 192.168.1.32 on
>> eth0 to 255.255.255.255 port 67 (xid=0x6d8d1a)
>> Jun  7 19:36:15 hhr-prd-be1 dhclient: DHCPOFFER of 192.168.1.32 from
>> 192.168.1.1
>> Jun  7 19:36:15 hhr-prd-be1 dhclient: DHCPACK of 192.168.1.32 from
>> 192.168.1.1
>> Jun  7 19:36:15 hhr-prd-be1 dhclient: bound to 192.168.1.32 -- renewal
>> in 34193 seconds.
>>
>>
>> the first server (the one with the IP 192.168.1.1) is responding with ACK:
>>
>> Jun  7 09:34:00 dp-c2-bl16 dnsmasq-dhcp[27774]:
>> DHCPREQUEST(tap347066a3-42) 192.168.1.33 fa:16:3e:5c:2e:fc
>> Jun  7 09:34:00 dp-c2-bl16 dnsmasq-dhcp[27774]: DHCPACK(tap347066a3-42)
>> 192.168.1.33 fa:16:3e:5c:2e:fc host-192-168-1-33
>> Jun  7 09:34:25 dp-c2-bl16 dnsmasq-dhcp[27774]:
>> DHCPREQUEST(tap347066a3-42) 192.168.1.32 fa:16:3e:76:aa:56
>> Jun  7 09:34:25 dp-c2-bl16 dnsmasq-dhcp[27774]: DHCPACK(tap347066a3-42)
>> 192.168.1.32 fa:16:3e:76:aa:56 host-192-168-1-32
>> Jun  7 19:13:38 dp-c2-bl16 dnsmasq-dhcp[27774]:
>> DHCPREQUEST(tap347066a3-42) 192.168.1.33 fa:16:3e:5c:2e:fc
>> Jun  7 19:13:38 dp-c2-bl16 dnsmasq-dhcp[27774]: DHCPACK(tap347066a3-42)
>> 192.168.1.33 fa:16:3e:5c:2e:fc host-192-168-1-33
>> Jun  7 19:36:15 dp-c2-bl16 dnsmasq-dhcp[27774]:
>> DHCPREQUEST(tap347066a3-42) 192.168.1.32 fa:16:3e:76:aa:56
>> Jun  7 19:36:15 dp-c2-bl16 dnsmasq-dhcp[27774]: DHCPACK(tap347066a3-42)
>> 192.168.1.32 fa:16:3e:76:aa:56 host-192-168-1-32
>> Jun  7 19:36:15 dp-c2-bl16 dnsmasq-dhcp[27774]:
>> DHCPDISCOVER(tap347066a3-42) fa:16:3e:76:aa:56
>> Jun  7 19:36:15 dp-c2-bl16 dnsmasq-dhcp[27774]:
>> DHCPOFFER(tap347066a3-42) 192.168.1.32 fa:16:3e:76:aa:56
>> Jun  7 19:36:15 dp-c2-bl16 dnsmasq-dhcp[27774]:
>> DHCPREQUEST(tap347066a3-42) 192.168.1.32 fa:16:3e:76:aa:56
>> Jun  7 19:36:15 dp-c2-bl16 dnsmasq-dhcp[27774]: DHCPACK(tap347066a3-42)
>> 192.168.1.32 fa:16:3e:76:aa:56 host-192-168-1-32
>>
>>
>> While the other (192.168.1.2) sends the NACK:
>>
>> Jun  7 09:34:00 dp-c1-bl16 dnsmasq-dhcp[635]:
>> DHCPREQUEST(tap347066a3-42) 192.168.1.33 fa:16:3e:5c:2e:fc
>> Jun  7 09:34:00 dp-c1-bl16 dnsmasq-dhcp[635]: DHCPACK(tap347066a3-42)
>> 192.168.1.33 fa:16:3e:5c:2e:fc host-192-168-1-33
>> Jun  7 09:34:16 dp-c1-bl16 dnsmasq-dhcp[635]:
>> DHCPREQUEST(tap347066a3-42) 192.168.1.33 fa:16:3e:5c:2e:fc
>> Jun  7 09:34:16 dp-c1-bl16 dnsmasq-dhcp[635]: DHCPACK(tap347066a3-42)
>> 192.168.1.33 fa:16:3e:5c:2e:fc host-192-168-1-33
>> Jun  7 19:13:38 dp-c1-bl16 dnsmasq-dhcp[635]:
>> DHCPREQUEST(tap347066a3-42) 192.168.1.33 fa:16:3e:5c:2e:fc
>> Jun  7 19:13:38 dp-c1-bl16 dnsmasq-dhcp[635]: DHCPACK(tap347066a3-42)
>> 192.168.1.33 fa:16:3e:5c:2e:fc host-192-168-1-33
>> Jun  7 19:36:15 dp-c1-bl16 dnsmasq-dhcp[635]:
>> DHCPREQUEST(tap347066a3-42) 192.168.1.32 fa:16:3e:76:aa:56
>> Jun  7 19:36:15 dp-c1-bl16 dnsmasq-dhcp[635]: DHCPNAK(tap347066a3-42)
>> 192.168.1.32 fa:16:3e:76:aa:56 lease not found
>> Jun  7 19:36:15 dp-c1-bl16 dnsmasq-dhcp[635]:
>> DHCPDISCOVER(tap347066a3-42) fa:16:3e:76:aa:56
>> Jun  7 19:36:15 dp-c1-bl16 dnsmasq-dhcp[635]: DHCPOFFER(tap347066a3-42)
>> 192.168.1.32 fa:16:3e:76:aa:56
>> Jun  7 19:36:15 dp-c1-bl16 dnsmasq-dhcp[635]:
>> DHCPREQUEST(tap347066a3-42) 192.168.1.32 fa:16:3e:76:aa:56
>> Jun  7 19:36:15 dp-c1-bl16 dnsmasq-dhcp[635]: DHCPACK(tap347066a3-42)
>> 192.168.1.32 fa:16:3e:76:aa:56 host-192-168-1-32
>>
>> my question is that from the client we can see the request targeting
>> 192.168.1.1:
>> Jun  7 19:36:15 hhr-prd-be1 dhclient: DHCPREQUEST of 192.168.1.32 on
>> eth0 to 192.168.1.1 port 67 (xid=0x196ca4cf)
>>
>> why the 192.168.1.2 is sending the NACK in this case?
>>
>> Thank you,
>> Laszlo
>>
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>> Dnsmasq-discuss at lists.thekelleys.org.uk
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>>
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