do not respond to DHCPINFORM requests

[Glenn Satchell]

Can you add an "option hostname" and send that out with the original dhcp
response? Don't know if that will work but simple to try.

regards,
-glenn

On Sat, May 11, 2013 2:55 am, Sergey Skobkarev wrote:
> Hi Glenn,
>
> Thank you for your advise. It seems like a viable workaround for my
> Windows
> 7 machines issue.
>
> However, I also used DHCPINFORM's for assigning hostnames to my lab
> computers after their re-imaging, and unfortunately your solution will not
> help in that case, so I'm still going to revise the server's code and try
> to fix it if it won't take to much time and effort.
>
> Cheers,
>
> --
> Sergey Skobkarev
> CIS System Administrator
> University of the Fraser Valley
>
>
>
> On Thu, May 9, 2013 at 4:21 AM, Glenn Satchell
> <glenn.satchell at uniq.com.au>wrote:
>
>> Hi Sergey and Randall
>>
>> Several years ago I added this to my dhcpd.conf to try to work around
>> one
>> cause of dhcpinform: the browser querying for wpad options. Not sure if
>> the \000 is still needed, but it does no harm. In the comments PRL is
>> the
>> "parameter request list".
>>
>> # Windows systems accept the WPAD option for setting up their proxy
>> server
>> # (Autodetect proxy settings):
>> # (According to Ted Lemon, "text" will get the Microsoft
>> # NUL termination bug heuristic applied, and "string" won't!
>> option wpad code 252 = text;
>> option wpad "http://proxy/proxy.pac\000";
>>
>> # Special config for Windows ("MSFT 5.0") systems.
>> # Note this does not catch Windows CE.
>> class "MSFT" {
>>   match if substring(option vendor-class-identifier, 0, 4) = "MSFT";
>>   # They put 252 on the DHCPINFORM's, but not on the DHCPREQUEST's
>>   # PRL.  So we over-ride the PRL to include 252 = 0xFC, which will
>>   # send the option at DHCPDISCOVER/DHCPREQUEST time, and wil also
>>   # suppress the DHCPINFORMS!  They seem to cache it.
>>   option dhcp-parameter-request-list = concat(option
>> dhcp-parameter-request-list, fc);
>> }
>>
>> regards,
>> -glenn
>>
>> On Thu, May 9, 2013 9:44 am, Sergey Skobkarev wrote:
>> > Hi Randall,
>> >
>> > I'm having the same problem with 'custom' groups inside subnets.
>> Windows
>> 7
>> > machines successfully get IP, domain, DNS server and other parameters
>> on
>> > IP renew, but then they (IE?) send DHCPINFORM request, receive wrong
>> DNS
>> > server and domain information and "fix" their lease details. As a
>> result,
>> > I cannot assign proper 'custom' options.
>> >
>> > If I remove 'authorative' from the configuration file, dhcpd stops
>> > responding to DHCPINFORM requests, so it works as a temporary
>> solution.
>> > However, I however have some other usage for DHCPINFORM's and would
>> like
>> > to fix the server and get proper INFORM answers.
>> >
>> > I was going to hack the code, but then saw your message and decided to
>> ask
>> > if you succeeded in that already and if you did, would you send me a
>> patch
>> > or at least point out where should I start?
>> >
>> > My DHCP server's version is 4.1.1 (Release: 34.P1.el6.centos), but
>> I'll
>> > probably use the latest code for hacking/recompiling.
>> >
>> > Thank you,
>> >
>> >
>> > --
>> > Sergey Skobkarev
>> >
>> >
>> > _______________________________________________
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>> > dhcp-users at lists.isc.org
>> > https://lists.isc.org/mailman/listinfo/dhcp-users
>>
>>
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