DNS Suffixes

it2b

I am migrating my company to our corporate parent's domain. I have a DNS server with multiple zones in my source domain. PCs have had no problems after migration.

I moved my first server had problems resolving host names. The TCP/IP properties are set to append the primary suffix. I had to use the "Append these suffixes" option to add both the domains.

Since both zones are on the same DNS server that I am pointing to, should I have to do this? I thought the server would look in all zones before trying recursion or failing.

Claymoore

The DNS suffixes are used to fully qualify single-lable names so that DNS resolution is used instead of netbios or WINS.

For example:
2 domains - domain1.local and domain2.ad (in that order)
2 servers - server1.domain1.local and reallylongservername.domain2.ad

client1 pings server1 (NETBios \ WINS is used LAST)
client1 tries to resolve server1.domain1.local and succeeds

client1 pings reallylongservername
client1 tries to resolve reallylongservername.domain1.local and fails
client1 tries to resolve reallylongservername.domain2.ad and succeeds
client1 cannot resolve reallylongservername using NETBios \ WINS because it is too long.

Here's a better flowchart:
Name Resolution

it2b

I think I see now. My workstations resolve both domains because they have both domains added to their search list. The old DNS domain is assigned via DHCP scope options. The new domain became the primary DNS suffix when the PC joined the new domain.

The server (who does not use DHCP) received the new primary DNS suffix when it joined the new domian. It could no longer append the suffix of the source domain.

So I guess then even if you have multiple zones on a server, if you are trying to resolve host names you need to have a suffix search list on the connection.