Clients cannot connect to server and visa versa

Hi

check if the its firewall is running and turn it off..
if you dont have any firewall running,,

no firewalls running... this is on a lan... Windows Firewall / ICS is disabled...

oops

if you dont have any firewall running,,
then check connectivity to the server
can you ping client to server and vice versa ?

Try to Ping the server from any of the clients using the IP adres
Also Ping on server 127.0.0.1 to ensure NIC and TCP/IP Stack is OK

Please post results.

yes, tcpip is ok.  I can ping the server itself at 127.0.0.1 from the server.  I can go to the clients and ping its address ok... which is 192.168.1.5

I just cannot go to \\server\share from the clients nor can I get to any of the client shares from the server like \\client\share

what error you get when you access shared folder on both sides ??

"Windows cannot find \\client\share"... Check the spelling and try again, or try searching for the item by cli cking the start button and clicking search

did you give users permission to the shared folder ?
if yes try add everyone also to check if it's permission issue or not?

Check the services...
Check if there are any servie in hung state (starting OR stopping)
Also check the required services are running.
Ref: http://technet.microsoft.com/en-us/library/cc785922(WS.10).aspx
(This URL gives you the picture of default state of services in 2003)

Note: Following services should be automatic and started in DC
File Replication, Netlogon, DNS, Windows Time

Thank you.  I will check this article and post results back here asap.  I am also about to upgrade this server from win 2k3 standard to enterprise.

Also check following.

DCDIAG
DCDIAG /test:DNS
Netdiag

This is absolutely baffling.  I am nearly at a point of considering re-installing the operating system on this server!  It is like it just disappeared from our network.  Even though it is online, I cannot see it from any other system in our network, nor can I see any of our workstations from it while I am logged into it.  Does DNS have anything to do with it?  It is running Active Directory.  Very lost with this!  ...and the only thing I did yesterday was temporarily enable Routing and Remote Access, and it went downhill from there.  in need of some real help here...

No need to reinstall:

You are experiencing what happens with a Multihomed domain controller.

Are both nics still enabled?

You are able to ping the server/client, but unable to access shares.

Please let us know the following.

How many DCs you have?
Did you find any errors in DCDIAG or DCDIAG /test:DNS or NETDIAG?
All the required services are running?
Is there any errors in event log (IPSEC / DNS / Netlogon / any other, which you find relevant to this problem)?

Try to access //localhost; and let us know
Did you restart the server and check the problem?

Ah yes, both NICs are still enabled.  I will try to disable the one I am not using and see if I get better results.  I have one NIC that is labeled LAN (the one I need) and another one labeled WAN (which I don't need).  I only have just this one domain controller.  We plan on getting a BDC this next year, but for now, we have just this one.  If this still doesn't fix the problem, I'll post results of the diags here next.  Thanks!

Wow!  Lots of potential issues here!  Thanks for your help on a Christmas ChiefIT!  ...and Merry Christmas to everyone!  Ok, I am going to start by clearing the ARP cache because disabling that second NIC and rebooting didn't yield any better results.  So, I am going to go through these paces here as you have presented and will keep us posted...

Ok, I think I might have just stumbled onto something... in doing as much investigation as I possible could into this matter, it being one of the more bizarre and challenging server issues I have ever run across (a server disappearing off the network and workstations disappearing out of view from the server), I was inside the protocol settings of the TCP/IP protocol, in the Advanced section, and then the WINS tab, there is a setting for the "NetBIOS setting".  Upon noticing that the option "Disable NetBIOS over TCP/IP" was checked, thinking this wasn't correct, I enabled this setting, rebooted and now things seem to be getting back to normal.  I can see the server from my workstations and visa versa.  This is very curious how this setting got set like this since I did not make this configuration change in this protocol.  This isn't something that enabling Routing and Remote Access could have caused, would it?  Just very bizarre...

Now I need to make sure that I haven't messed up anything else along the way in everything else I have done.  One thing... is it absolutely necessary to have DNS running on the server?  Is that required?  

This is one of the first Active Directory servers that I have had to administer as I am typically a web server admin, and we NEVER use AD for web servers.  However, with this new contract I am on assisting this company with their server, I am now in the thick of admin'ing an AD server.  Are there any good AD resources to learn AD and all of it's ins and outs?

Thanks for the help!  I believe the main / underlying issue was with the second NIC.  After disabling that, all was well.