We're thinking of removing WINS from our internal network. Will doing so have a negative impact on Exchange Server?
Microsoft recommends that you use WINS; though the service isn't required, Microsoft won't support Exchange configurations that don't use it. The Microsoft article "Exchange Server 2003 and Exchange 2000 Server require NetBIOS name resolution for full functionality" (http://support.microsoft.com/?kbid=837391) clearly states this recommendation but doesn't clearly explain why WINS is required or what to do if you're determined to remove it.
I can think of a few circumstances in which Exchange and its components actually require WINS to resolve short NetBIOS names. Exchange System Manager (ESM) uses WINS, although you can work around that requirement by editing your management workstations' local HOSTS files. WINS is necessary during Exchange installation because the Setup utility makes a variety of WINS queries to locate existing Exchange resources—no word yet on whether this process will change in the next version of Exchange (code-named Exchange 12), which is set to use the Windows Installer in response to the Windows Server System Common Engineering Criteria. Clustered Exchange servers require WINS because short network names are an integral part of Cluster service name resolution and resource location.
If none of this information dissuades you from getting rid of WINS, be sure that all domain controllers (DCs), Global Catalog (GC) servers, and Exchange servers have the correct DNS suffix information defined for the root domain and all child domains. Doing so will help ensure that servers in the child domains can find servers in the root domain. If the fact that Microsoft doesn't guarantee that you'll be able to run Exchange without WINS causes you to reconsider your plans, you might consider this alternative: Add two WINS servers (for redundancy) to your organization and configure your Exchange servers to use those WINS servers. These servers will use few resources, so once you've installed them you can pretty much leave them alone. Other applications—including Windows—can do without WINS, but by keeping the service available to Exchange, you'll insulate yourself from potential problems.