Intermittent vpn flapping and disconnection.VPN Tunnel is established, but not traffic passing through.Phase 2 (IPsec) security associations fail.

Phase 1 (ISAKMP) security associations fail.There are Four most common issue we generally face while setting up vpn tunnel. While creating vpn tunnels, we generally encounter common issue and as a set of rules’, there are basically few checks that you need to validate for when a tunnel fails to establish. As a network engineer, it doesn’t matter what vpn device you are using at each end of the vpn site. I love to work on CLI (command line) and cisco Firewall is my favorite and have successfully created vpn tunnels including Cisco ASA, SonicWALL, Cyberoam, Checkpoint, Palo-Alto and lots more. In this article i wanted to describe the steps of Troubleshooting a site-to-site VPN tunnel, most of vpn appliances provide the Plenty of debugging information for engineer to diagnose the issue. The first and most important step of troubleshooting is diagnosing the issue, isolate the exact issue without wasting time. (Image Source – Network Troubleshooting is an art and site to site vpn Troubleshooting is one of my favorite network job.I believe other networking folks like the same. SITE TO SITE IPSEC VPN PHASE-1 AND PHASE-2 TROUBLESHOOTING STEPS, NEGOTIATIONS STATES AND MESSAGES MM_WAIT_MSG

Fortigate debug ipsec