After reinstalling Debian—whether version 10 (Buster) or 11 (Bullseye)—one of the most common headaches is losing your network configuration. If your setup uses bonded interfaces (LACP / 802.3ad) for redundancy, the reload wipes out all those settings. The system comes up, but there’s no proper connectivity until bonding is restored.This guide walks through the exact steps we follow at SupportPRO to bring the network back up after a reload, get the bonds working again, and make sure SSH is accessible.

Step 1: Find the Correct Interfaces

Start by listing your interfaces:

ip a

You’ll usually see something like eno1, enp9s0f0, or similar. The one with the smaller number is typically your public NIC. Make note of both interfaces that are connected to your public network — you’ll need them for bonding.

Step 2: Bring Up a Temporary Network

Before setting things up permanently, it’s easier to create a temporary connection so you can install packages or fetch updates. Adjust interface names and IPs as needed for your server:

Once this is done, check if you can ping an external host (for example, 8.8.8.8). If that works, you’re good to move on.

Step 3: Update and Install Required Packages

Next, refresh the package index and install a couple of tools that help with bonding:

If this step fails, it’s usually because the Debian repository URLs are outdated — that’s common when working with older versions.

Step 4: Fixing the Repository List (for Debian 10)

Debian 10’s repositories have moved to the archive servers. You’ll need to point APT to those.
Open /etc/apt/sources.list and replace the contents with:

Then run:

apt update

That should fix the issue and let you proceed with package installation.

Step 5: Set Up the Bonding Configuration

Now it’s time to make the bonding permanent.
Edit the network configuration file:

nano /etc/network/interfaces

Add or replace the content with:

Replace eno1 and eno2 with your actual interface names — check using ip a if unsure.

Step 6: Restart the Network

To apply the configuration:

systemctl restart network

After restarting, your data center team will need to rebond the ports on the switch. Once they’ve done that, the system should come back online with full internet access.

Step 7: Check SSH Settings

If SSH isn’t accessible, open /etc/ssh/sshd_config and make sure this line is present (or uncommented):

PermitRootLogin yes

Then restart SSH:

systemctl restart sshd && systemctl restart ssh

Step 8: Verify Access and Reboot

Try logging in via SSH:

ssh root@your-server-ip

If it connects, reboot the server once to confirm the changes persist:

reboot

After the reboot, your bonded interface (bond0) should be up and stable.

Quick Recap

Step	Action	Purpose
1	Identify interfaces	Determine public NICs
2	Temporary setup	Enable short-term connectivity
3	Install tools	Add ifenslave and net-tools
4	Fix APT sources	Update repositories if needed
5	Configure bonding	Edit /etc/network/interfaces
6	Restart & notify DC	Activate bonding on both ends
7	Enable SSH	Allow root login if blocked
8	Verify	Test connectivity and reboot

Final Thoughts

Once you’ve done this process a few times, it starts to feel pretty straightforward. The tricky part is just getting that temporary connection up long enough to install the right tools. After that, it’s mostly about following the steps in the right order and making sure your data center rebonds the ports on their end.

Bonding’s a small task that makes a big difference. You get better uptime, load balancing, and peace of mind knowing your public network won’t drop because of a single cable. We at SupportPRO do this routinely for hosting providers worldwide, so if you’d rather not wrestle with it yourself, we can take care of it anytime.