Remote users having trouble accessing OWA
We are using NT4 and Exchange 5.5. Up until about two months ago our users were able to use Outlook Web Access from remote locations. Now they receive the error "Cannot find server" or "DNS error" when they attempt to access Outlook via the Web from a remote location. We can access OWA internally on our network and log in to Outlook but are unable to access it from a remote location. What can I check to solve the problem? Thanks.
The first thing to check is name resolution. You are getting errors that indicate a name resolution failure (e.g., a failure to locate the requested system using its name). This means you'll want to check the DNS settings on the OWA client side and make sure the OWA client has good name resolution to the OWA server. NSLookup and ping are often helpful in resolving this. If you have already verified healthy name resolution, the next step would be to check your browser settings and make sure its not misconfigured in any respect (e.g., proxy settings missing or present when they should not be).
If this does not help, the next step would be to take a network capture using Network Monitor of the attempt to logon to OWA. I recommend taking simultaneous captures on both ends (OWA client and OWA server) so that you can reconcile captured activity between them.
This was first published in January 2003