Created attachment 218027 [details]
12.2-BETA has a new issue with VNET that 12.1-RELEASE didn't have.
Initially when a list of jails are created all can be pinged. However, after the default ARP timeout, the last jail attached to the bridge fails to respond. If the ARP for the last jail is statically set (arp -s) it will again respond to pings. The problem only effects the last jail attached to the bridge regardless of the number of jails or which one is last.
My /etc/jails.conf is attached
*** This bug has been marked as a duplicate of bug 249399 ***