As an alternative to a fake tag to remove the empty field, would it work to
declare a static dhcp-range in my configuration file to cover the addresses
that are managed by the hostsfile?
On Monday, December 16, 2013 2:47 PM, Maule Mark <[email protected]> wrote:
I don't think our client is asking for a lease time. Or if it was, I would
also expect it to make the request on the very first DHCPREQUEST, which gets
the correct 1h lease.
>
>
>The double comma is to establish a placeholder field where we can plug in an
>optional tag: field, which we do in certain situations to influence the next
>dhcp exchange for this id. The program we use to manage this file rigidly
>expects each line to have the same number of fields if this optional tag
>exists or not.. I'll try putting a fake tag in that field and see if it
>solves the 2m lease time issue.
>
>
>
>
>
>
>
>On Monday, December 16, 2013 2:28 PM, Simon Kelley <[email protected]>
>wrote:
>
>On 16/12/13 19:36, Maule Mark wrote:
>>> I'm seeing an unexptected (to me) behavior when using a dnsmasq
>>> hostsfile and dhcp. To start, my interface (pmi_if) is configured with
>>> a lease time of 1h (the default), and I have a blank hostsfile.
>>>
>>> dhcp-leasefile=/var/lib/axiom/dnsmasq_pmi.leases
>>> dhcp-hostsfile=/var/lib/axiom/dnsmasq_pmi_hostsfile
>>> dhcp-range=172.30.80.0,static,255.255.255.0
>>> dhcp-range=172.30.80.200,172.30.80.240,255.255.255.0
>>> dhcp-lease-max=255
>>> dhcp-option=option:dns-server,172.30.80.1
>>> dhcp-option=option:router,172.30.80.1
>>> dhcp-option=option:ntp-server,172.30.80.1,172.30.80.2,172.30.80.3
>>> dhcp-option=option:default-ttl,50
>>> dhcp-option=option:all-subnets-local,1
>>> dhcp-script=/var/lib/axiom/dhcp-script-pmi.sh
>>> dhcp-boot=/pds/pxe/pxelinux.0,172.30.80.1
>>>
>>> Clients boot and are assigned dhcp addresses as expected. We have a
>>> program in our software stack that looks for heartbeat messages on this
>>> pmi_if, and when detected, constructs a hostsfile entry for the client
>>> that looks like this:
>>>
>>> [root@pilot2 axiom]# cat dnsmasq_pmi_hostsfile
>>> 00:21:28:A1:F3:F2,00:21:28:A1:F3:F3,,WN5080020001592690,172.30.80.128
>>> 00:21:28:A1:CA:3A,00:21:28:A1:CA:3B,,WN5080020001592691,172.30.80.129
>>>
>>> The clients are running udhcpc from busybox.
>>>
>>> Everything works as expected until the clients get toward the end of
>>> their 1h lease period at which point the clients start sending
>>> DHCPREQUEST requests. It seems at this point, that the leases granted
>>> are now 120s. Here's some syslog output showing the first DHCPREQUEST
>>> being sent about 55 minutes into the 1h initial lease. Why did dnsmasq
>>> return a lease time of 12s in this case?
>>>
>>> 2013-12-16 19:33:42.253+00:00 pilot2 dnsmasq-dhcp[23916]: 208328817
>>> DHCPREQUEST(pmi_if) 172.30.80.129 00:21:28:a1:ca:3a
>>> 2013-12-16 19:33:42.253+00:00 pilot2 dnsmasq-dhcp[23916]: 208328817
>>> tags: known, pmi_if
>>> 2013-12-16 19:33:42.253+00:00 pilot2 dnsmasq-dhcp[23916]: 208328817
>>> DHCPACK(pmi_if) 172.30.80.129 00:21:28:a1:ca:3a WN5080020001592691
>>> 2013-12-16 19:33:42.253+00:00 pilot2 dnsmasq-dhcp[23916]: 208328817
>>> requested options: 1:netmask, 3:router, 6:dns-server, 12:hostname,
>>> 2013-12-16 19:33:42.253+00:00 pilot2 dnsmasq-dhcp[23916]: 208328817
>>> requested options: 15:domain-name, 28:broadcast, 42:ntp-server
>>> 2013-12-16 19:33:42.253+00:00 pilot2 dnsmasq-dhcp[23916]: 208328817
>>> bootfile name: /pds/pxe/pxelinux.0
>>> 2013-12-16 19:33:42.253+00:00 pilot2 dnsmasq-dhcp[23916]: 208328817
>>> server name: 172.30.80.1
>>> 2013-12-16 19:33:42.253+00:00 pilot2 dnsmasq-dhcp[23916]: 208328817 next
>>> server: 172.30.80.3
>>> 2013-12-16 19:33:42.253+00:00 pilot2 dnsmasq-dhcp[23916]: 208328817 sent
>>> size: 1 option: 53 message-type 5
>>> 2013-12-16 19:33:42.253+00:00 pilot2 dnsmasq-dhcp[23916]: 208328817 sent
>>> size: 4 option: 54 server-identifier 172.30.80.3
>>> 2013-12-16 19:33:42.253+00:00 pilot2 dnsmasq-dhcp[23916]: 208328817 sent
>>> size: 4 option: 51 lease-time 2m
>>> 2013-12-16 19:33:42.253+00:00 pilot2 dnsmasq-dhcp[23916]: 208328817 sent
>>> size: 4 option: 58 T1 56s
>>> 2013-12-16 19:33:42.253+00:00 pilot2 dnsmasq-dhcp[23916]: 208328817 sent
>>> size: 4 option: 59
T2 1m41s
>>> 2013-12-16 19:33:42.253+00:00 pilot2 dnsmasq-dhcp[23916]: 208328817 sent
>>> size: 4 option: 1 netmask 255.255.255.0
>>> 2013-12-16 19:33:42.253+00:00 pilot2 dnsmasq-dhcp[23916]: 208328817 sent
>>> size: 4 option: 28 broadcast 172.30.80.255
>>> 2013-12-16 19:33:42.253+00:00 pilot2 dnsmasq-dhcp[23916]: 208328817 sent
>>> size: 5 option: 15 domain-name axiom
>>> 2013-12-16 19:33:42.253+00:00 pilot2 dnsmasq-dhcp[23916]: 208328817 sent
>>> size: 18 option: 12 hostname WN5080020001592691
>>> 2013-12-16 19:33:42.253+00:00 pilot2 dnsmasq-dhcp[23916]: 208328817 sent
>>> size: 20 option:209 70:78:65:6c:69:6e:75:78:2e:63:66:67:2f:64...
>>> 2013-12-16 19:33:42.253+00:00 pilot2 dnsmasq-dhcp[23916]: 208328817
sent
>>> size: 4 option:208 f1:00:74:7e
>>> 2013-12-16 19:33:42.253+00:00 pilot2 dnsmasq-dhcp[23916]: 208328817 sent
>>> size: 12 option: 42 ntp-server 172.30.80.1, 172.30.80.2, 172.30.80.3
>>> 2013-12-16 19:33:42.253+00:00 pilot2 dnsmasq-dhcp[23916]: 208328817 sent
>>> size: 4 option: 3 router 172.30.80.1
>>> 2013-12-16 19:33:42.253+00:00 pilot2 dnsmasq-dhcp[23916]: 208328817 sent
>>> size: 4 option: 6 dns-server 172.30.80.1
>>>
>>>
>>> Is there a default lease time of 120s for client requests whose
>>> addresses which match a hoststfile entry?.
>>
>>No, there's no 120s default, but there is a 120s floor (ie no lease less
>>the 120s will be issued).
>>
>>Note that the DHCP _client_ can ask for a particular lease time, it
>>would be interesting to see if it's sending a lease-time option for 120s
>>or less in the DHCPREQUEST packet.
>>
>>Another potential issue is your hostfile:
>>
>>00:21:28:A1:CA:3A,00:21:28:A1:CA:3B,,WN5080020001592691,172.30.80.129
>>
>>I've not looked, but the double comma may concievably confuse the parser
>>such that it looks like a zero, which then gets interpreted as a lease
>>time, and transformed to 120s by the floor.
>>
>>I think that is the most likely explanation.
>>
>>Cheers,
>>
>>Simon.
>>
>>
>>>
>>> thanks
>>> Mark
>>>
>>>
>>>
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>>
>>
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