I have followed https://premier.microsoft.com/premier/library/default.aspx?path=/premier/kb/en-us/Q278/8/87.ASP?KBID=Q278887 I can send video and transfer files with users behind the ISA Server but I can't with user's out side the ISA Server. MSN Chat works fine through the firewall to users on the internet. Just can't get Video/Voice or file transfers to work. Has anyone had any success with this? Thanks, George