pfSense

Where using IKEv2 with PSK on a site to site VPN, where the identifiers are IPs, and the remote is a FQDN, you end up with something like the following:

Jun 22 16:29:44    charon: 01[NET] <con3|1> sending packet: from 172.27.44.52[500] to 172.27.44.51[500] (300 bytes)
Jun 22 16:29:44    charon: 01[NET] <con3|1> received packet: from 172.27.44.51[500] to 172.27.44.52[500] (76 bytes)
Jun 22 16:29:44    charon: 01[ENC] <con3|1> parsed IKE_AUTH response 1 [ N(AUTH_FAILED) ]
Jun 22 16:29:44    charon: 01[IKE] <con3|1> received AUTHENTICATION_FAILED notify error
Jun 22 16:29:44    charon: 01[IKE] <con3|1> received AUTHENTICATION_FAILED notify error

or:

Jun 22 16:27:14    charon: 05[IKE] <con3|3> no shared key found for '172.27.44.52' - '172.27.44.51'
Jun 22 16:27:14    charon: 05[IKE] <con3|3> no shared key found for '172.27.44.52' - '172.27.44.51'

where ipsec.secrets is configured like:

%any 172.27.44.51 : PSK 0sFjeRIUgndkfjEiufeskFD

Change %any to the specific local identifier and it works fine.

172.27.44.52 172.27.44.51 : PSK 0sFjeRIUgndkfjEiufeskFD