Peering authentication is the process by which network devices, such as routers or switches, verify each other's identity before forming a trusted connection known as a peering relationship. This verification ensures that only authorized and legitimate devices can exchange routing information or data. Commonly used in internet service provider (ISP) networks and large enterprise environments, peering authentication helps prevent unauthorized access, route hijacking, and other security threats. Methods for peering authentication include the use of passwords (such as MD5 authentication), digital certificates, or cryptographic keys. By enforcing strict authentication measures, organizations can maintain the integrity, confidentiality, and availability of their network communications.