Editing Virtual private network (section)

==Trusted delivery networks==
Trusted VPNs do not use cryptographic tunneling; instead, they rely on the security of a single provider's network to protect the traffic.<ref>{{Cite book |last=Cisco Systems, Inc. |url=https://books.google.com/books?id=3Dn9KlIVM_EC |title=Internetworking Technologies Handbook |publisher=Cisco Press |year=2004 |isbn=9781587051197 |edition=4 |series=Networking Technology Series |page=233 |quote=<nowiki>[...] VPNs using dedicated circuits, such as Frame Relay [...] are sometimes called </nowiki>''trusted VPN''s, because customers trust that the network facilities operated by the service providers will not be compromised. |access-date=2013-02-15}}
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* [[Multiprotocol Label Switching]] (MPLS) often overlays VPNs, often with quality-of-service control over a trusted delivery network.
* L2TP<ref>[https://www.ietf.org/rfc/rfc2661.txt Layer Two Tunneling Protocol "L2TP"] {{Webarchive|url=https://web.archive.org/web/20220630094743/https://www.ietf.org/rfc/rfc2661.txt |date=30 June 2022 }}, {{IETF RFC|2661}}, W. Townsley ''et al.'', August 1999</ref> which is a standards-based replacement, and a compromise taking the good features from each, for two proprietary VPN protocols: Cisco's [[L2F|Layer 2 Forwarding (L2F)]]<ref>[https://www.ietf.org/rfc/rfc2341.txt IP Based Virtual Private Networks] {{Webarchive|url=https://web.archive.org/web/20220709081725/https://www.ietf.org/rfc/rfc2341.txt |date=9 July 2022 }}, {{IETF RFC|2341}}, A. Valencia ''et al.'', May 1998</ref> (obsolete {{As of | 2009 | alt =as of 2009}}) and Microsoft's [[Point-to-Point Tunneling Protocol|Point-to-Point Tunneling Protocol (PPTP)]].<ref>[https://www.ietf.org/rfc/rfc2637.txt Point-to-Point Tunneling Protocol (PPTP)] {{Webarchive|url=https://web.archive.org/web/20220702054527/https://www.ietf.org/rfc/rfc2637.txt |date=2 July 2022 }}, {{IETF RFC|2637}}, K. Hamzeh ''et al.'', July 1999</ref>

From a security standpoint, a VPN must either trust the underlying delivery network or enforce security with a mechanism in the VPN itself. Unless the trusted delivery network runs among physically secure sites only, both trusted and secure models need an authentication mechanism for users to gain access to the VPN.{{fact|date=June 2023}}