OPEN DOOR NETWORKS SHIPS WHO'S THERE? FIREWALL ADVISOR FOR MAC OS X

ASHLAND, OR. -- August 20, 2001 -- Open Door Networks Inc. today announced
that it was shipping a Mac OS X specific version of its Who's There?
Firewall Advisor. Who's There? Firewall Advisor, available since January
for Mac OS 8 and 9, provides an important aspect of Internet security by
helping users analyze, investigate and respond to access attempts to their
Macintosh. Who's There? Firewall Advisor for Mac OS X is an OS X native
version of the application that provides analysis and advice specific to
the Mac OS X environment.

"Mac OS X's Unix base presents some interesting security challenges for Mac
users," said Alan Oppenheimer, president of Open Door Networks and
co-author of the new book "Internet Security for Your Macintosh: A Guide
for the Rest of Us". "Who's There? Firewall Advisor for Mac OS X alerts
users to attacks that might not have been significant under previous
versions of the Mac OS, and provides them with advice and suggestions
specific to Mac OS X," Oppenheimer continued.

With the ever-growing number of computers connected to the Internet through
"always on" connections, there has been a significant increase in the
number of hackers attempting to infiltrate those computers. Personal
firewalls have been developed to thwart those attempts. As the number of
attempts has risen, however, users have become increasingly confused as to
the degree to which they should be concerned and what they can do in
response. Who's There? Firewall Advisor works with the user's firewall to
answer those questions.

Who's There? Firewall Advisor for Mac OS X works with Symantec's recently
released Norton Personal Firewall for Mac OS X, which is based on
technology licensed from Open Door. Features of Who's There? Firewall
Advisor for Mac OS X include:

o Advanced Access History window displaying all logged access attempts and
including security risk level and host name of the accessor.

o Windows summarizing access attempts by service type and accessor IP address.

o Built-in information about the most common attacks and their
applicability specifically to the Mac OS X environment.

o Automated "Whois" lookup to determine details of the accessor's network,
including administrator name, address, phone number and email.
Administrator's address plotted on a world map.

o Automated drafting of an email that can be used to notify the
administrator of the access attempt and provide the administrator with
details that may be useful in tracking the attempt.

Features new to the OS X version include a column indicating whether an
email has been sent in response to a particular access attempt, and support
for new top-level domain names like .biz and .info.

A free evaluation version of Who's There? Firewall Advisor for Mac OS X is
available directly from Open Door's Web site. Who's There? for Mac OS X can
also be purchased from the site, for $49. Registered users of previous
versions of Who's There? can upgrade to the Mac OS X version for $29.
Volume and site licenses are also available. Additional information on
Who's There? can be obtained from the Who's There? Web site at
http://www.opendoor.com/whosthere/.

Open Door Networks, Inc. is a leading provider of Internet security
solutions for the Macintosh, and the developer of Mac OS 9's TCP/IP File
Sharing feature. Open Door was founded in January, 1995 by Alan
Oppenheimer, an 11-year Apple veteran and co-creator of the AppleTalk
network system. Open Door's mission is to provide Macintosh users with
Internet solutions that are as easy-to-use and as powerful as the Macintosh
itself. Open Door Networks is based in Ashland, Oregon.