Where does Proxmox get the gateway IP?

[pxmxadm]

Hi,

pardon my lack of networking understanding. I have vmbr0 assigned an IP, say, 10.10.10.10/24 with gateway 10.10.10.1. I then want to tag vlans on on bridge. So I try to create vmbr0.1080 with an IP 10.10.11.11/24 in vlan 1080 but if I specify vlan 1080 gateway IP in the web UI, it throws error:

Parameter verification failed. (400)

gateway: Default gateway already exists on interface 'vmbr0'

If I don't specify the gateway and commit the changes anyway, somehow I am able to ping it. Where does it get the gateway info from? Thanks.

 

[bbgeek17]

Hi @pxmxadm ,

There is no gateway configured for your VLANs. You have Layer 2 (L2) connectivity, allowing hosts on the same subnet to broadcast and receive ARP messages from other hosts within the subnet.

To examine your routing table for more details, you can do:
ip r

Any traffic that the host cannot reach directly will be sent to the gateway of your primary network. This means the source IP will be the original one, not the VLAN IP.

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