I'm using an old ESXi server to run Proxmox Backup Server. It has 192GB of RAM but never uses more than about 99GB (according to the Memory usage graph on the Server Administration page). I'm assuming most of that is just caching indexes and...
indeed I mean "Firewall" (post edited).
If Firewall not enable, no rules are applied so LXC should works out the box.
ipv6 is, by default, SLAAC which doesn't dhclient. I have no experience with dhcp ipv6.
EDIT:
try increase timeout in...
PVE Firewall is only active if set to "Yes" under Datacenter \ Firewall \ Options \ Firewall.
Try set to "Off" to globally turno off PVE firewall, as the default.
BTW, IPv6 clients require accepting ICMPv6 packets.
as VM within PVE or physical external ?
is your Edge router have IPv6 ?
IPv6 uses RA to get IPv6 prefix from router then generates its own IPv6 itself , it's not like IPv4 DHCP.
BTW, /etc/sysctl.conf is no more used since Debian13, *.conf are in...