Show threadBruce Simpson, Ph.D.Mar 8
And the name of that #StrongES extension? net.inet.ip.source_address_validation, which, incidentally, is missing from the #FreeBSD ip(4) man page just now, along with its close cousin, net.inet.ip.rfc1122_strong_es. See #IETF #RFC1122 https://datatracker.ietf.org/doc/html/rfc1122
Volunteers?
RFC 1122: Requirements for Internet Hosts - Communication Layers

This RFC is an official specification for the Internet community. It incorporates by reference, amends, corrects, and supplements the primary protocol standards documents relating to hosts. [STANDARDS-TRACK]

IETF Datatracker
Show threadBruce Simpson, Ph.D.Mar 8
In theory this should be fine, modulo #IPv4 #StrongES restrictions; #FreeBSD
introduced a further out-of-box hardening of this which may affect such
"unnumbered" interfaces; although, like legacy #Cisco IOS platforms, the
address of the bridge should be "reachable" from all other physical links
on the IPv4 node. I smell a patch for someone!