One VM's IP can connect to the Internet, while the other IPs can't?


New Member
Oct 23, 2023
Hello everyone.

I'm trying to set up Proxmox 7.4-17 VM networking. I have 4 IP addresses plus the host's one assigned to the VPS I'm trying to run Proxmox on.

Currenly, only one VM with an IP, let's call it, VM_IP_4, can access the Internet. Other VMs with the other IPs can't.

I can't understand why that is. I have set up my /etc/network/interfaces like this:

source /etc/network/interfaces.d/*

auto lo
iface lo inet loopback

auto enp3s0
iface enp3s0 inet static
address HOST_IP/19
gateway GATEWAY_IP
dns-search lo
up route add -net HOST_IP netmask gw GATEWAY_IP dev enp3s0
post-up echo 1 > /proc/sys/net/ipv4/conf/enp3s0/proxy_arp

auto vmbr0
iface vmbr0 inet static
address HOST_IP/22
bridge-ports none
bridge-stp off
bridge-fd 0
post-up echo 1 > /proc/sys/net/ipv4/ip_forward

And my /etc/network/interfaces.d/vm-routes like this:

iface vmbr0 inet static
up ip route add VM_IP_1/22 dev vmbr0
up ip route add VM_IP_2/22 dev vmbr0
up ip route add VM_IP_3/22 dev vmbr0
up ip route add VM_IP_4/22 dev vmbr0

Subnet is /22. Can someone help me?

Thank you.
Has it something to do with the fact that all IPs come from the same subnet? But only one works, whatever VM I use it on. The others never work, on any VM.


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