MERCUR Mailserver - Version 4.2 MERCUR Mailserver Version 4.2 Dispatching email within an Intranet or the Internet is an essential service for all businesses. MERCUR offers the necessary features to provide an efficient and effective communications medium. These include Security features using IP-Caching Firewall, List Server, Remote Configuration via a Web Browser, Dial-Up-connectivity (Modem, ISDN- Card), dedicated connectivity (ISDN-Router) or connectivity over the network (Router) to your ISP. MERCUR Mailserver for Windows NT, Windows 2000 and WIndows XP.