When to assign an IP address to a proxmox network bridge?

[BrettR]

Hello.

I have a proxmox server that has two configured network bridges (i.e. vmbr0, and vmbr1).

Here is most of the /etc/network/intefaces file from my proxmox server:
---------------------------------------------------------
auto lo
iface lo inet loopback

iface eth0 inet manual

iface eth1 inet manual

iface eth2 inet manual

iface eth3 inet manual

auto vmbr0
iface vmbr0 inet static
address 172.16.20.40
netmask 255.255.255.0
gateway 172.16.20.1
bridge_ports eth0
bridge_stp off
bridge_fd 0

auto vmbr1
iface vmbr1 inet manual
bridge_ports none
bridge_stp off
bridge_fd 0
#Isolated VM Network
---------------------------------------------------------

Under what condition, should I assign an IP address (and netmask, and gateway)
to the 'vmbr1' interface?


(I have a VM on my system that uses both the 'vmbr0' and 'vmbr1' network bridges (i.e. virtual switches).

Here is most of the /etc/network/interfaces file from that VM:
----------------------------------------------------------
source /etc/network/interfaces.d/*

# The loopback network interface
auto lo
iface lo inet loopback

# The primary network interface # (This interface is configured to use the 'vmbr0' bridge)
auto ens18
iface ens18 inet static
address 172.16.20.39
netmask 255.255.255.0
gateway 172.16.20.1
dns-nameservers 172.16.20.1

# The secondary (VM-only) private network interface #(This interface is configured to use the 'vmbr1' bridge)
auto ens19
iface ens19 inet static
address 10.10.10.2
netmask 255.255.255.0
dns-nameservers 10.10.10.2
----------------------------------------------------------

Thanks!

--Brett

 

[wolfgang]

Hi,

the IP on the bridge is needed if you like to communicate from the bridge to Guest.
It is not necessary for Guest to Guest communication.

 

[BrettR]

Thank you for your help.

May I pose one more question..or two?

In my particular case..

The proxmox server bridge has the following configuration
(taken from the /etc/network/interfaces file):

auto vmbr0
iface vmbr0 inet static
address 172.16.20.40
netmask 255.255.255.0
gateway 172.16.20.1
bridge_ports eth0
bridge_stp off
bridge_fd 0

And a Windows VM connected to the 'vmbr0' bridge has it's own network address
i.e.
auto ens18
iface ens18 inet static
address 172.16.20.41
netmask 255.255.255.0
gateway 172.16.20.1
dns-nameservers 172.16.20.1

So, are we saying that the vmbr0 bridge must have an IP address assigned to it..in order for
a host outside of the 172.16.20.x network..to be able to establish a connection with
the 172.16.20.41 host?

Thanks!

 

[wolfgang]

Correct you need the Ip address on the vmb0 for host communication.
The VM can communicate with the outer world without the host IP.