Help needed: When EC2 instance is stopped and restarted, VPN no longer works

[wyun]

Help needed:
When EC2 instance is stopped and restarted, VPN no longer works. The user script is the same, I wonder why restarting a working EC2 instance will not create a working VPN any more....

[sarfata]

The script is only executed once when the machine starts, not when it reboots. There are different reasons why it's not working anymore:

• Some services might not have started automatically
• IP address might have changed

In any case, you can just create a new instance instead of re-using the same one. It would cost you the same. Have you tried this?

[wyun]

Thanks for the quick reply.

I modified the script to include a variable $DYNDNS_URL, then at the end of the script, it will automatically updates the dynamic DNS with the new IP address:
curl -s $DYNDNS_URL

This all works well. So for the second reason, it's usually not an issue for changed IP.

I did try to start new instance, it works well. Just trying to figure out why the same script cannot be restarted.

Thanks.

[sarfata]

@wyun the script is ran only the first time you boot the machine. Not every time. The ip addresses are saved in ipsec.conf and I think your problem is that they are not updated when you start the machine the second time.

[wyun]

That makes sense. Thank you for the help. I will restart new instances then.