Exhibit 10.21 THIS AMENDMENT NO. 1 dated as of October 4, 1999 to the Amended and Restated Investors' Rights Agreement (the "Agreement") dated as of July 16, 1999, by and among DSL.net, Inc., a Delaware corporation (the "Company"), the investors...Investors' Rights Agreement • October 5th, 1999 • DSL Net Inc • Telephone communications (no radiotelephone)
