From outside, can you do 'telnet XXX.XXX.XXX.XXX:88 and have it connect ok? This is a basic connectivity test. What is the error you are getting, anything in your iislogs on the server listening on port 88? those are a couple things to see if all moving parts are configured properly.
Steve Schofield
Windows Server MVP - IIS
MCTS - Windows Hosting
http://weblogs.asp.net/steveschofield
http://www.iislogs.com
http://www.orcsweb.com/
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