Troubleshooting Tip: The IPv4 address is not supported for Peer ID for IPsec vpn tunnels

[rbarnes]

Description	This article describes that the IPv4 address is not supported for a Peer ID setup for IPsec VPN tunnels.
Scope	FortiGate v7.2, v7.4, v7.6.
Solution	Configured is a Site-to-site dialup tunnel using Peer ID due to there being multiple tunnels on the same FortiGate in the following example. The tunnel will not come up. The IPv4 Peer ID setting is causing the tunnel to fail and not come up. All other configurations are correctly set and in place. Remote tunnel settings: config vpn ipsec phase1-interface     edit "bgpfun"         set interface "port3"         set mode aggressive         set peertype any         set net-device disable         set proposal aes128-sha1 aes256-sha1         set localid "192.168.194.99"         set localid-type address         set remote-gw 192.168.194.99         set psksecret xxxxx A     Next end Local tunnel settings: config vpn ipsec phase1-interface     edit "bgpfun"        set type dynamic        set interface "port3"        set mode aggressive        set peertype one        set net-device disable        set proposal aes128-sha1 aes256-sha1        set dpd on-idle        set peerid "192.168.194.99"        set psksecret xxxxx        set dpd-retryinterval 60    next en IKE debug output. Snippet: 2025-03-05 16:3:46.059299 ike 0:bgpfun:2783: peer is FortiGate/FortiOS (v0 b0)2025-03-05 16:34:46.059703 ike 0:bgpfun:2783: VID FRAGMENTATION 4048B7D56EBCE88525E7DE7F00D6C2D32025-03-05 16:34:46.060180 ike 0:bgpfun:2783: VID FRAGMENTATION  02025-03-05 16:34:46.060704 ike 0:bgpfun:2783: peer identifier IPV4_ADDR 192.168.194.99 2025-03-05 16:34:46.061145 ike 0:bgpfun:2783: error, received 'c' expected '192.168.194.99'0::2784: peer identifier IPV4_ADDR 12.168.194.992025-03-05 16:34:49.009670 ike 0:bgpfun: ignoring IKE request, incorrect ID. 2025-03-05 16:34:46.010366 ike 0::2782: peer identifier IPV4_ADDR 192.168.194.99 2025-03-05 16:34:46.010784 ike 0:bgpfun: ignoring IKE request, incorrect ID. The debug shows it is failing. This is because FortiGate cannot use IPv4 as Peer ID is not supported as per the known issue 1109028. Configure a text string as the Peer ID and Local ID in the tunnel setup. config vpn ipsec phase1-interface     edit "bgpfun"         set interface "port3"         set mode aggressive         set peertype any         set net-device disable         set proposal aes128-sha1 aes256-sha1         set localid "bgpfun”         set remote-gw 192.168.194.99         set psksecret xxxxx     Next end The local tunnel settings: config vpn ipsec phase1-interface     edit "bgpfun"         set interface "port3"         set mode aggressive         set peertype one         set net-device disable         set proposal aes128-sha1 aes256-sha1         set remote-gw 192.168.194.50         set peerid "bgpfun"         set psksecret xxxxx    next end This will work. This behavior will be fixed in v7.6.3.