There is a thread in "23.1 Legacy Series" about how FRR BGP with MD5 should work out of the box, but the setkey does not actually set the md5-key.
I tried to set the md5-key manually as described the old forum post, and the peer went up.
My setting looks right, I have the "Local Initiater IP" filled in with the source IP I want in my setkey, and the peer IP as the peer. But no keys created.
Was this working and is now broken again?
It looks like /usr/local/opnsense/scripts/frr/register_sas is not being run.
The original bug-report is at https://github.com/opnsense/plugins/issues/3372 if anyone else can fix it.