Open Door Networks has released a public beta of DoorStop, a software-based firewall for individual Macintosh servers. Unlike expensive hardware solutions, DoorStop operates only on the Macintosh on which it is installed, providing flexible blocking of TCP services. You can block any TCP connection from any address or range of addresses, block access to all TCP services on the server, block accesses to particular IP addresses on a multihomed server, and keep a log of all denied and allowed accesses. DoorStop should be of special interest to anyone running Open Door’s ShareWay IP, which provides AppleShare-over-IP services to Macs running Personal File Sharing. As we commented in "Share and Share IP Alike" in TidBITS 436, ShareWay IP creates some security issues – DoorStop should significantly alleviate those concerns if installed correctly. DoorStop requires a PowerPC-based Mac, Mac OS 8.1, and Open Transport 1.3 or later. Pricing has yet to be set, and version 1.0b1, which expires 01-Oct-98, is a 680K download.