I have a win server 2008 DC and a lot of XP clients,some of users in DC are tested and worked until I want to share files for some users
I logon as a domain user and share a folder,for permisions,I want to select another user but my domain name didn't show(my computer name show) so I can't select and also see other users!!!!
I have admin user.
Can You Help Me?

Is this your first time doing this? Have this problem occur before? If no, that means you must have changed some settings recently.

yes,this is the first time,
what settings you mean?
in server or clients?

Your computer. Tell me what steps you did to share the files. Be as specific as possible.

for adding in domain
system properties> computer name>change> select domain>enter domain name>in appear dialog box >administartor and its password,then ...
restart computer and logon as a domain user
for sharing:
in sharing tab>permisions>add>
i must see the domain name as location,but my computer name appear!!!

I found a way that solve problem,one of my coworkers found it(but didn't explain it)
we set win server 2008(as DC Server) IP as a DNS for XP clients,file sharing works
but I can't understand why???
can any one explain it for me??

Good to hear your problem is solved. Lol, i should have thought of that but i take your problem as an advanced and serious one. DNS is shortform for Domain Name System. Its a basic way how computer share data with one another on the internet or in private networks. Look at the picture i got from the internet maybe that will help you out.

thanks for your attention,I think I must learn more about network,I learn about network in situation that happen in work!!
can you give me some file or sites to help me more or giud me to learn ??

So did the link help you. Which part of networking are you intrested in and wanted to study. If you have any questions or problems about networking, you can always come back to daniweb. I wiill be more than willing to helo you. :)

Hi I would like to add a site that is worth its weight in gold

Its Microsoft, you can use most of it free , but if you are a student I think you get a membership fo a very good price.
As long as you are a paid member you can download and use almost all Microsoft programs
Server 2008 R2 - All office suites Vista etc.
I've been a member for years and would never think of giving my membership up.