Hello All, We have Exchange 5.5 SP4 on Windows NT 4.0 with SP 6a. When I check Internet Mail Service Queue, I see that some of messages remain and when I check the details, it says "host unreachable" althoug our DNS works properly. I checked it with nslookup on mail server ant it returns the mx records of these "unreachable" domains. Any idea? Nortel Networks Netas 35 years in communications