IKEv2 Tunnel Fails: Cisco vs Palo vs Juniper

Three vendors. One VPN. Zero uptime.

If you’ve ever built a site-to-site IPsec tunnel between Cisco ASA, Palo Alto NGFW, and Juniper SRX, you’ve likely run into the same problem: the tunnel refuses to come up, and every vendor blames the other.

This article walks through the most common IKEv2 failure scenarios across these platforms, what the logs really mean, and how to quickly align proposals so your tunnel actually works.