Question 360
The partner IPsec log for an R82 site-to-site tunnel records NO_PROPOSAL_CHOSEN during IKE negotiation after its administrator removed an old encryption suite. Both endpoints can exchange UDP 500, and peer credentials have been checked. An alternate diagnosis concerns the requirement to handle IPv6 payloads under supported site-to-site VPN, for which a colleague suggests use the matching IPv6-in-IPv6 tunnel scheme and IKEv2. Based on the recorded symptoms, which corrective step should have priority?
Explanation
Correct Answer
Both IKE/IPsec peers must agree on compatible proposals. This directly addresses the documented incident evidence.
Incorrect Answers
R82 IPv6 VPN tunneling uses IPv6 within IPv6 and IKEv2, but the current evidence calls for a different R82 operation.
Data associations still need matching selectors and permitted traffic; this does not resolve the observed condition.
Both sides need consistent configured IKE authentication secrets, yet that applies to authenticate a third-party IPsec peer with a shared secret rather than the observed issue.