Question

How to user droplet UserData to change sshd_config

I’m trying the following code to change the IP ssh listens to. Unfortunately this doesn’t work as I can’t successfully connect after droplet is created.

Tested in an existing dropley with su privileges it works. I’m creating a droplet from an image where su only have access after authentication. Does it have any connection?

I’m trying this on a Debian 8.

#!/bin/bash apt-get update export PRIVATE_IPV4=$(curl -s http://169.254.169.254/metadata/v1/interfaces/private/0/ipv4/address) sed -i “s/.ListenAddress./ListenAddress $PRIVATE_IPV4 /g” /etc/ssh/sshd_config ssh restart


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Hi Thanks for answering. Indeed, my sed command was replacing both lines. But that is not an issue to log in to ssh, after I manually give a reset cycle from dashboard.

The problem is that ssh restart doesn’t do anything. I assume this is because in the image I’m building from I removed root access, and the other 2 users have not access to run commands without password.

I also added

#cloud-config
power_state:
  mode: reboot

with no success

@admin87f7492443

You should be able to use something such as:

sed -i "0,/ListenAddress.*/c\ListenAddress $PRIVATEIPV4" /etc/ssh/sshd_config

Since there’s two instances of ListenAddress in the default Debian sshd_config file, when you run your sed, it actually modifies both instances as the s/ and /g matches all instances, not just one.

By default, you’ll see:

#ListenAddress ::
#ListenAddress 0.0.0.0

When running your sed replacement, you end up with:

ListenAddress PRIVATE_IP ::
ListenAddress PRIVATE_IP 0.0.0.0

Where PRIVATE_IP is your Droplet Private IP.

When running the command I’ve provided, it’ll only modify the first instance and it’ll remove the line entirely and replace it with just:

ListenAddress PRIVATE_IP

That said, unless you’re connecting over a VPN, you won’t be able to connect to SSH using the Private IP, so if you plan on connecting sans VPN, you’d need to change that to the public IP.