We, National Institute of Public Health in Norway, run LISTSERV 1.8d on Win NT with Exchange Server 5.5. LISTSERV and Exchange run on separate machines and different domains. For our internal users the system works fine. Now that we want to make our lists available for people outside the institute we are having problems getting it to work as we want. If anyone else have got a similar setup to work we will be happy to get in touch with you. Here are some details about our system, and a short description of what is working and what is not: Our system is set up on two servers where "machine1" is running our mailserver and "machine2" is running LISTSERV. There is a firewall between the two servers and machine1 is inside the FW and machine2 is placed on the DMZ-segment of the FW together with the web-server. Our primary domain is folkehelsa.no and we have a subdomain for the lists, list.folkehelsa.no. If an internal user, [log in to unmask], subscribes to a list he get all the expected response from LISTSERV. After confirming his subscribtion to a list he can send messages to it and operate it as defined. When an external user with email address other than @folkehelsa.no send a subscription request to a list the user is added to the list as he is supposted to, but he never receive any confirmation form the list. This user can now send messages to the list as any of the internal members and the mail is distributed to all the internal members of the list as normal. Still the external member doesn't receive any messages from the list. From this we tend to conclude that the communication between LISTSERV and Exchange works fine and that the reason for the problem is that there might be something missing in our Exchange setup which allow mails that are sent from other domains/machines to be forwarded to users. Does anyone have any ideas on this? We would be grateful for any help. Tor-Arne Bertheussen, National Institute of Public Health, Oslo, Norway