[CentOS] Re: ISC dhcpd and Vista clients

Glenn centos at 1bigadmin.biz
Thu Jul 31 20:30:33 UTC 2008

At 03:41 PM 7/31/2008, you wrote:
>on 7-31-2008 12:24 PM Tim Utschig spake the following:
>>On 07/31/08 12:02, Scott Silva wrote:
>>>The other answer is to get ISC dhcpd to honor the broadcast flag, 
>>>and broadcast all packets instead of unicasting the answer 
>>>packets. That I can't find a setting for.
>>I have no Vista clients to test with, but have you tried 
>>"always-broadcast on;" ?
>>  From "man dhcpd.conf" on CentOS 5.2:
>>     always-broadcast flag;
>>     The  DHCP and BOOTP protocols both require DHCP and BOOTP clients
>>     to set the broadcast bit in  the  flags  field  of  the  BOOTP
>>     message header.   Unfortunately, some DHCP and BOOTP clients do
>>     not do this, and therefore may not receive responses from the
>>     DHCP server.    The DHCP server can be made to always broadcast
>>     its responses to clients by setting this flag to 'on' for the
>>     relevant scope; relevant scopes would be inside a conditional
>>     statement, as a parameter for a class, or as a parameter for a
>>     host declaration.   To avoid creating excess broadcast  traffic
>>     on  your network, we recommend that you restrict the use of this
>>     option to as few clients as possible.   For example, the
>>     Microsoft DHCP client is known not to have this problem, as are
>>     the OpenTransport and ISC DHCP clients.
>SO... I have to flood my network with broadcast traffic or pay the 
>microsoft extortion... Bill strikes again!
>Thanks for that. I had been reading the dhcp man page (I should say 
>book! What a long one.) I guess I missed that. I'll have to set any 
>Vista clients to named hosts so I can limit the traffic.
>According to that man page, ISC implies that Vista is broken, and 
>Microsoft implies that ISC is broken. Were playing the blame game again!
>How fun!  ;-P
>And I thought it was going to get boring...

Nice. Microsoft is regressing to its good old formula of flooding the 
LAN with lots of 'me too' and 'I am here' packets. Way to improve efficiency!

Yep. Think I'll stick with XP SP2 where and when I can, until I am 
forced to move on.


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