Slow Logon to Lion Server from Snow Leopard Machines

Hi Everyone,

I am usually okay with computers however something has been baffling me for a while now!

We have recently updated our server from an ageing Tiger server to a Lion server. (Mac Mini Server)

We have a suite of Mac minis that are running 10.7.4 and have no trouble connecting to the server in fact they sign a relatively quickly.

We also have a set of MacBooks that are currently all updated to Snow Leopard (10.6)

The issue we are having is with those MacBooks:

When the user attempts to access their network share from any of those MacBooks running Snow Leopard the login works however it can take up to 2 min to login. This does happen over the wireless network, however I have also checked it by plugging them in with an ethernet cable and they exhibit the same behaviour.

This is obviously quite frustrating for all the people using the MacBooks.

I got strange feeling that the check box somewhere that I've missed.

Any help would be greatly appreciated.