VM cannot ping interface proxmox et not acces internet


Hi everyone
I have a proxmox server i have private subnet with VMS but i can’t ping gateway of proxmox so internet too.
my set up on proxmox
vmbr0 public ip of dedibox bridge
vmbr1 private subnet bridge
vmbr2 private subnet bridge

iptables -t nat -A POSTROUTING -s ‘’ -o vmbr0 -j MASQUERADE
and ip_forward=1

on vm
but cannot ping why what i miss
Or it is necessry to use rpn or ipfailover i don’t understand
thank for your return


I resolve some troubles by my self now i can ping my interfaces it was iptables now i allow icmp but my vm cannot always reach google or dns by ping or nslookup. I think at first it is iptables so i try to allow all dns traffic from any src to any dest but nothing change. i think normally when nat is configure you don’t need to allow all dns trafic maybe i am wrong.
my resolv.conf of my vm have dns or ip of host proxmox or dns online but