1 EXHIBIT 23.1 CONSENT OF ERNST & YOUNG LLP, INDEPENDENT AUDITORS We consent to the references to our firm under the captions "Selected Consolidated Financial Data" and "Experts" and to the use of our reports dated January 17, 2000, in Amendment No. 3 to the Registration Statement (Form S-1 No. 333-96171) and related Prospectus of Juniper Networks, Inc. for the registration of its common stock issuable under the conversion of convertible notes. Our audits also included the financial statement schedule listed in Item 16(b) of this Registration Statement. This schedule is the responsibility of the Company's management. Our responsibility is to express an opinion based on our audits. In our opinion, the financial statement schedule referred to above, when considered in relation to the basic financial statements taken as a whole, presents fairly in all material respects the information set forth therein. /s/ Ernst & Young LLP Palo Alto, California February 23, 2000