IPFW/IPv6 problem with JAIL: JAIL cannot ping -6 host until host first pings jail (ipv6)

Hello,

I've got a problem with recent CURRENT, running vnet JAILs.
FreeBSD 15.0-CURRENT #28 main-n267432-e5b33e6eef7: Sun Jan  7 13:18:15 CET 2024 amd64

Main Host has IPFW configured and is open for services like OpenLDAP on UDP/TCP and ICMP
(ipfw is configured via rc.conf in this case, host is listening on both protocol families
IPv4 and IPv6). 

The host itself has openldap-server 2.6 as a service. The host's interface is igb0 with
assigned ULA. JAILs (around eight jails) are sharing their vnet interfaces via a bridge with
the same physical device as the host (igb0). After a while (the time elapsed is unspecific)
the jail is unable to contact the host via IPv6: neither UDP, TCP nor ICMP sent from the JAIL
is reaching the host. IPv4 is working like a charme! No problems there.

When pinging the Jail from the main host via ping -6, the jail is responding! After the first
ping -6, the jail now is able to ping -6 the main host.

After a fresh reboot, the problem is not present and occurs after a while and it seems to
happen first to very active jails.

Kind regards,

oh


-- 
O. Hartmann