I want to add another domain name to the search order but whn I tried
either the service doesn't start properly or from Windows the DNS
Suffix search order isn't displayed and or set properly. Example
scenario.

I first set the dhcpd.conf settings for the multiple names.
....
option domain-name "linux.net linux.org";
....


Then from Windows PC I run ipconfig /all
....
DNS Suffix Search List. . . . . . : linux.net linux.org
....

Then I run a ping command
C:\> ping www
Ping request could not find host www. Please check the name and try
again.

As you can it didn't work. However, if the option is set to
"linux.net" only, then the ping of www works. BTW, www is mapped to
the IP address of the DNS server from within the /var/named zone file.
When I ping the FQDN of www.linux.net everything works.

C:\>ping www.linux.net

Pinging linux.linux.org [192.168.0.202] with 32 bytes of data:

Reply from 192.168.0.202: bytes=32 time=296ms TTL=64
Reply from 192.168.0.202: bytes=32 time=296ms TTL=64
Reply from 192.168.0.202: bytes=32 time=296ms TTL=64
Reply from 192.168.0.202: bytes=32 time=296ms TTL=64