Problem with DHCP-enabled clients

[Simon Hobson]

Phusion wrote:

>I am having a problem with DHCP-enabled clients on my test network.
>The servers are running on the test.com domain while the DHCP-enabled
>clients are on the mdnlan.test.com domain. The DHCP computers get
>domain names of computername.mdnlan.test.com. The DNS server is named
>smdndnsp1.test.com. This server also runs the DHCP service. These
>computers are having problems pinging the computers on the test.com
>domain.
>
>- ping from testcomp.mdnlan.test.com to dns.test.com works
>- ping from testcomp.mdnlan.test.com to dns fails


Sounds like a normal dns problem, not a dhcp one.

When you ping dns.test.com your client resolves the address 
"dns.test.com" and gets an address.

When you ping "dns" the client is almost certainly resolving 
dns.mdnlan.test.com and not getting an address for it - so it fails.

Several ways around this :

1) Always use FQDN - it's the safest option anyway as it avoids any 
possibility of confusion.

2) Set the clients search options. Clients typically have one or both of :

a) a specific search list, so you could set mdnlan.test.com and 
test.com as the list and the client would try dns.mdnlan.test.com 
then dns.test.com.

b) search parents of the clients domain, so again it would try 
dns.test.com when the first query failed.

3) Add a dns entry for your subdomain, so that dns.mdnlan.test.com 
resolves (CNAME for dns.test.com ?).


Depending on the client, you may or may not be able to set a domain 
search list via DHCP.