I have entered the IP 192.168.xx.x, Error: Example: 192.168.1.1/24 Valid CIDR Range: 8-32

[Helposoft Staff]

The error message indicates that Proxmox requires the IP address to be in CIDR notation (e.g., 192.168.1.1/24). CIDR notation specifies both the IP address and the network mask.

Step-by-Step Guide to Add a Bridge with CIDR Notation​

1. Identify Your Network CIDR:
   • Determine the appropriate CIDR notation for your network. For example, if your subnet mask is 255.255.255.0, the CIDR notation is /24.
2. Convert Your IP Address to CIDR Notation:
   • For an IP address like 192.168.xx.x, you need to append the subnet mask in CIDR notation.
   • Example: 192.168.xx.x/24 for a subnet mask of 255.255.255.0.
3. Create a Bridge in Proxmox:
   • Open the Proxmox web interface and log in.
   • Go to Datacenter > your node > System > Network.
   • Click on Create > Linux Bridge.
4. Enter the Bridge Details:
   • Name: vmbr1 (or any name you prefer)
   • Bridge Ports: eth0 (or your physical network interface)
   • IPv4/CIDR: 192.168.xx.x/24
   • Gateway: Enter your gateway IP, e.g., 31.172.80.254
5. Save the Configuration:
   • Click Create and then Apply Configuration.

Example Configuration​

Proxmox Bridge Settings:

• Name: vmbr1
• Bridge Ports: eth0
• IPv4/CIDR: 192.168.xx.x/24
• Gateway: 31.172.80.254

Adding Multiple IPs (If you have multiple IPs)​

If you have multiple IP addresses, you need to configure the additional IPs within the virtual machine or as additional IPs on the bridge in Proxmox.
For example:

1. Edit the Bridge Configuration:
   • Go to Datacenter > your node > System > Network.
   • Select the bridge (vmbr1) and click Edit.
2. Add Additional IPs (if required):
   • Use the format 31.172.80.x/24 for each additional IP you want to add.
3. Configure Additional IPs in the VM:
   • Inside the VM, configure the network interface to use the assigned IP address.
   • Edit /etc/sysconfig/network-scripts/ifcfg-eth0 with the correct IP and gateway information.

Inside the VM:​

sudo nano /etc/sysconfig/network-scripts/ifcfg-eth0

Update the file with your network settings:

TYPE=Ethernet
BOOTPROTO=static
NAME=eth0
DEVICE=eth0
ONBOOT=yes
IPADDR=31.172.80.2
NETMASK=255.255.255.0
GATEWAY=31.172.80.254
DNS1=8.8.8.8

Restart Network Service:​

sudo systemctl restart network

By following these steps, you should be able to configure the network bridge in Proxmox and assign IP addresses correctly using CIDR notation.