How i can connect again to my instance?

Question

I'd made a big mistake today while i tried to make my ubuntu server more safe.

With ufw tools i'd denied the ssh access to all ipv4 adresses except my ip (or at least that's what I thought). In the network tab on lightsail web console, the firewall allows any ipv4 but it didn't work. Now i'm unnable to connect with windows cmd/pem key and lightsail ssh console. 😥

How i can recovery the access again?

I don't have any backup or snapshot. And this is my job project.

![SSH console](/media/postImages/original/IMJwj_jwqxQS-p-kcfEG-dkw)

Riku_Kobayashi · Answer

Hello.

Please try restoring your instance by following the steps in "An OS-level firewall is blocking SSH port access" in the following document.  
Create a snapshot from your existing Lightsail instance, and when restoring from that snapshot, configure a launch script to disable ufw.  
https://repost.aws/knowledge-center/lightsail-resolve-ssh-console-errors  
```
sudo ufw disable
sudo iptables -F
sudo mv /etc/hosts.deny /etc/hosts.deny_backup
sudo touch /etc/hosts.deny
sudo systemctl enable sshd
sudo systemctl restart sshd
```

Manvitha Potluri · Answer

Step 1: Create a temporary recovery instance
Go to Lightsail Console.
Launch a new instance with the same OS as your original one (Ubuntu).
Wait for it to be ready, then SSH into this temporary instance via web or PuTTY.

Step 2: Attach your original disk to the recovery instance
In the Lightsail dashboard, stop the original instance (the one you're locked out of).
Go to Snapshots > Create Snapshot of the original instance’s disk (optional but good for safety).
Go to the Networking tab, click Create a new disk from this instance (or go to Storage).
Attach the disk to the recovery instance you created earlier.

Step 3: Mount the attached disk and fix UFW
SSH into the recovery instance.
run --> lsblk
Identify the attached volume (e.g., /dev/xvdf1)
Mount it:
sudo mkdir /mnt/recovery
sudo mount /dev/xvdf1 /mnt/recovery
**Disable UFW for the original system:**
sudo chroot /mnt/recovery
ufw disable
exit
**Unmount the disk:**
sudo umount /mnt/recovery

Step 4: Detach the disk and reattach to original instance
Stop the recovery instance.
Detach the volume from it.
Reattach the volume back to the original instance (if it was a root disk) or simply restart the original instance if the disk was never detached.
Start the original instance again.

Step 5: Try SSH again
Use the web SSH console or your .pem key from a terminal.

How i can connect again to my instance?

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