dhclient: ISP's server won't answer unicast DHCPREQUEST anymore

[Steve Clark]

On 12/12/2011 07:11 AM, Jiri Popelka wrote:
> On 12/12/2011 01:02 PM, Steve Clark wrote:
>> On 12/12/2011 03:15 AM, Jordan Russell wrote:
>>> A bizarre problem has appeared after upgrading from Fedora 14 to 15,
>>> which brought dhclient from 4.2.0-P2 to 4.2.1-P1.
>>>
>>> Since the upgrade (weeks ago), my ISP's DHCP server no longer responds
>>> to any of the unicast DHCPREQUEST packets sent by dhclient when it
>>> enters the RENEWING state. However, hours later, when dhclient reaches
>>> the REBINDING state and broadcasts instead, the server responds
>>> immediately, and the renewal succeeds.
>>>
>>>    DHCPREQUEST on eth1 to 10.72.0.1 port 67
>>>    DHCPREQUEST on eth1 to 10.72.0.1 port 67
>>>    DHCPREQUEST on eth1 to 10.72.0.1 port 67
>>>    [...]
>>>    DHCPREQUEST on eth1 to 255.255.255.255 port 67
>>>    DHCPACK from 10.72.0.1
>>>    bound to 76.x.x.x -- renewal in 14685 seconds.
>>>
>>> tcpdump confirms that the unicast DHCPREQUEST packets are making it out
>>> (with correct IP and MAC addresses), but no corresponding responses are
>>> coming in.
>>>
>>> Was there any change in dhclient 4.2.1 that might explain this? I'm
>>> using an empty dhclient.conf file just as I was prior to the upgrade.
>>> (Initially, Fedora 15 inserted dhcp-client-identifier and hostname
>>> settings into the config, but I've since removed both of those and
>>> restarted dhclient numerous times.)
>>>
>>> Also, as an interim workaround to cut back on the syslog spam, is there
>>> some way to force dhclient to broadcast all DHCPREQUEST packets (i.e.
>>> skip the RENEWING state)?
>>>
>>> Thanks.
>> I see the same behavior on Fedora 12 with
>> dhclient-4.1.1-18.P1.fc12.x86_64
>>
>> ...
>> Dec 11 06:01:41 joker dhclient[1829]: DHCPREQUEST on eth0 to 10.99.32.1 port 67
>> ...
>> Dec 11 06:02:23 joker dhclient[1829]: DHCPREQUEST on eth0 to 255.255.255.255 port 67
>> Dec 11 06:02:23 joker dhclient[1829]: DHCPACK from 10.99.32.1
>> Dec 11 06:02:23 joker dhclient[1829]: bound to xxx.xxx.xxx.66 -- renewal in 4264 seconds.
>
> I don't remember seeing this with previous versions,
> but it works with dhclient-4.2.3-4.P1.fc16.x86_64 (Fedora 16) for me.
> Dec 12 08:32:15 zepelin dhclient[1497]: DHCPREQUEST on br0 to 10.34.xxx.y port 67
> Dec 12 08:32:15 zepelin dhclient[1497]: DHCPACK from 10.34.xxx.y
> Dec 12 08:32:17 zepelin dhclient[1497]: bound to 10.34.24.zz -- renewal in 34601 seconds.
Where did you find that rpm? My google for it turned up nothing.

-- 
Stephen Clark
*NetWolves*
Sr. Software Engineer III
Phone: 813-579-3200
Fax: 813-882-0209
Email: steve.clark at netwolves.com
http://www.netwolves.com
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