User-Level Authentication in IPsec Scott Kelly IPsec Remote Access Working Group 47th IETF

Main Points Modifying/extending IKE probably not prudent Transition from legacy mechanisms to stronger ones is desirable and necessary Even if PKIs were widely deployed, they likely would not be entirely sufficient (passwords still required)

The Mechanism Establish IKE SA –server cert, no client auth –preshared key –server/client certs Establish phase 2 SA which permits authentication exchange If authentication succeeds, either –modify existing phase 2 attributes, or –drop SA(s) and negotiate new one(s)

Considerations Underlying requirements must be clearly understood Drawbacks –DoS susceptibility due to SA establishment prior to authentication if client not authenticated somehow Strengths –can periodically renew authentication without additional DH exchanges