AboveNet Communications Continues to Address Denial of Service Issues by Upgrading to Latest Juniper Networks Internet Processor II ASIC

Business Wire, April 18, 2000

Business Editors/High-Tech Writers

MOUNTAIN VIEW, Calif.--(BUSINESS WIRE)--April 18, 2000

Juniper Networks, Inc. (NASDAQ:JNPR) and Metromedia Fiber Network (MFN), Inc. (NASDAQ:MFNX), today announced plans to deploy Juniper Networks(R) new Internet Processor II(TM) ASIC within the AboveNet Communications, Inc. global IP network to strengthen security against denial of service (DOS) attacks.

Metromedia Fiber Network has been uncompromising in its pursuit of security capabilities to help to block and track DOS attacks to protect their customers by minimizing potential disruptions. "We have been building up security in our network against denial of service attacks and unauthorized access to application servers, but lacked an effective solution that let us apply complex filters and still maintain wire-speed performance," said Paul Vixie, senior vice president for Internet services at MFN. "The Internet Processor II is a valuable new addition to our arsenal of preventive measures against DOS attacks."

"The real uniqueness of the Internet Processor II lies in its ability to perform wire-rate filtering at high speeds -- from OC-48/STM-16 and up to OC-192c/STM-64," said Pradeep Sindhu, CTO of Juniper Networks. "By adding our new M160 Internet backbone routers using the Internet Processor II to the core of their network, MFN can look forward to blocking DOS attacks more effectively without compromising performance."

In addition to packet filtering, the Internet Processor II provides sampling, counting, and load balancing. MFN plans to use the sampling and logging capabilities of the Internet Processor II to better understand its network traffic patterns at a detailed level with a goal of optimizing traffic inside its global IP network.

About Juniper Networks

Juniper Networks, Inc. is a leading provider of purpose-built systems that meet the scalability, performance, density, and compatibility requirements of rapidly evolving, optically enabled IP networks. The company's purpose-built systems provide new IP infrastructure solutions for the world's leading service providers. Juniper Networks service, manufacturing teams, and IP engineers work closely with customers to build and support customer networks. The company is headquartered in Mountain View, California. For more information, please contact the company at 650 526 8000 or visit the Web site at http://www.juniper.net.

Juniper Networks is a registered trademark of Juniper Networks, Inc. Internet Processor II, JUNOS, M20, M40, and M160 are trademarks of Juniper Networks. All other trademarks, service marks, registered trademarks, or registered service marks may be the property of their respective owners.

About Metromedia Fiber Network

Metromedia Fiber Network, Inc., the leading provider of end-to-end optical network solutions, is revolutionizing the fiber optic industry. By offering virtually unlimited, unmetered bandwidth at a fixed cost, Metromedia Fiber Network is eliminating the bandwidth barrier and redefining the way broadband capacity is sold. Metromedia Fiber Network is extending metropolitan fiber optic infrastructure to the end user in strategic top-tier markets, enabling its customers to implement the latest data, video, Internet and multimedia applications. In addition to its current expansion in 51 cities in North America, Metromedia Fiber Network is establishing an international presence with planned fiber optic network builds in 16 cities throughout Europe.

Together with its subsidiaries, AboveNet Communications, Inc., a leading provider of co-location and Internet connectivity solutions, and Paix.net, Inc., the leading neutral Internet Exchange, Metromedia Fiber Network is unleashing the full potential of the Internet. The combined company facilitates the explosive growth of e-commerce and advanced Internet applications by delivering secure, reliable and scalable optical networks and IP services to Internet content and service providers, carriers and enterprise users worldwide. For more information about Metromedia Fiber Network, please visit the company's Web site at www.mmfn.com or AboveNet Communications at www.above.net.

AboveNet, Internet Service Exchange, ISX, and AboveNet Global One-Hop Network are trademarks of AboveNet Communications, Inc. All other company or brand names may be trademarks of the respective companies with which they are associated.

This news release contains certain forward-looking statements that involve risks and uncertainties. Factors that could cause or contribute to such risks and uncertainties include, but are not limited to, general economic and business conditions, competition, changes in technology and methods of marketing, and various other factors beyond the Company's control. This also includes such factors as described from time to time in the SEC filings by Metromedia Fiber Network, including the Company's most recently filed Form S-3 and its annual report on Form 10-K for the year ended December 31, 1999.