Default Route Goes Missing After Reboot in Proxmox VE 8.2.2: A Troubleshooting Guide

The Problem:

After upgrading to Proxmox VE 8.2.2, users have reported that their default route is missing after a reboot. This means that any traffic sent over the network will not be routed properly, resulting in connectivity issues with external networks.

Symptoms:

• Default route (0.0.0.0/0) is missing from the routing table
• Network connections are lost or become unresponsive
• Errors such as "no route to host" or "connection timed out"

Causes and Troubleshooting Steps:

While there isn't a single cause for this issue, several factors may contribute to it:

1. Network configuration: Verify that the network interface is configured correctly and has an IP address assigned.
2. Routing table: Check if the routing table is populated with the default route (0.0.0.0/0). You can use the command ip -4 addr show or ip -6 addr show to check for any errors.
3. Firewall rules: Ensure that there are no firewall rules blocking traffic on the network interface.
4. DHCP settings: Verify that DHCP is enabled and working correctly.

Step-by-Step Resolution:

To resolve this issue, follow these steps:

1. Check the network configuration: Verify that the network interface has an IP address assigned using ip addr show. If not, assign one manually or use DHCP.
2. Rebuild the routing table: Run the command pve-manager and then navigate to Network > Routing . Click on the three dots next to your network interface and select Add route . Add a new default route with destination 0.0.0.0/0, gateway <default gateway>, and metric 10.
3. Verify firewall rules: Check if there are any firewall rules blocking traffic on the network interface. You can use firewall-cmd --list-all to check for any active rules.
4. Restart the networking service: Run systemctl restart networking or service networking restart to apply changes.

Conclusion:

The default route disappearing after a reboot in Proxmox VE 8.2.2 is an issue that has left many users scratching their heads. By following these troubleshooting steps and verifying network configuration, routing table, firewall rules, and DHCP settings, you should be able to resolve this issue and get your networking back up and running smoothly.

Disclaimer:

This blog post provides a general guide for resolving the default route issue in Proxmox VE 8.2.2. While these steps may work for most users, it's essential to note that individual configurations and setups can vary greatly. If you're still experiencing issues after following these steps, please seek further assistance from the Proxmox community or support forums.