Multiple Domains possible?

Glenn Satchell Glenn.Satchell at
Mon Apr 21 12:51:10 UTC 2008

>Date: Sun, 20 Apr 2008 23:04:08 -0600
>From: "S Kalyanasundaram" <skalyanasundaram at>
>To: <dhcp-users at>
>Subject: Multiple Domains possible?
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>>I am running a Redhat Linux server running DHCP 3.01 and bind 9.2.4 I 
>>was wondering if it was possible to have DHCP hand out multiple 
>>domains to search through.
>>Right now I use the line:
>>option domain-name "e.d.c.b.a"
>>in my dhcp.conf file.
>>where a-e are parts of my domain. In my environment we are a 
>>subdomain for a larger environment. If for example hostA is on my 
>>network and I do a query it resolves fine as hostA.e.d.c.b.a. If 
>>hostB in on the upper domain, my DNS server tries to resolve it as 
>>hostB.e.d.c.b.a, then hands it off to alternate DNS servers but still 
>>as hostB.e.d.c.b.a, not hostB.d.c.b.a. If I manually put in the 
>>multiple search paths on specific machines everything works great and 
>>it resolves both hostA.e.d.c.b.a and hostB.d.c.b.a. I would love to 
>>have DHCP itself hand out the multiple domains, it is possible?
>I too have a somewhat similar scenario, where all the desktop machines gets 
updated in for example
> by the dhcp server (using ddns) and all the labs  machines have a A 
record entry in dns (manually entered)
>in the domain
>If suppose the user is trying to resolve his desktop simply with the host name 
"user1" it adds and resolve successfully 
>but if he tries for lab machine "labnode1" it tries, 
instead how to make it to search in also?
>If I keep multiple "option domain-name" the latest one is taken.
>Is there a solution for this?
>Thanks in advance,
>  -Kalyan
3.0.1 is truely ancient, so you should upgrade. The latest V3 is 3.1.0,
(previous versions went to 3.0.6). 3.1.0 supports option domain-search:

man dhcp-options
     The domain-list data type specifies a list of domain  names,
     a  space between each name and the entire string enclosed in
     double quotes.   These  types  of  data  are  used  for  the
     domain-search  option  for  example,  and encodes an RFC1035
     compressed DNS label list on the wire.
     option domain-search string;

       The domain-search option  specifies  a  'search  list'  of
       Domain  Names  to  be  used  by  the client to locate not-
       fully-qualified domain names.  The difference between this
       option  and historic use of the domain-name option for the
       same ends is  that  this  option  is  encoded  in  RFC1035
       compressed labels on the wire.

Not all clients may support this setting though. Guess you need to try
it and see. Either way an upgrade to a newer version of dhcpd is a very
good idea.


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