Related

can i run my own debian based OS on a droplet? Question Question
When will Debian 9 be avialable? Question Question

Question

How to user droplet UserData to change sshd_config

Posted January 27, 2017 2.1k views
DebianDeployment

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 PRIVATEIPV4=$(curl -s http://169.254.169.254/metadata/v1/interfaces/private/0/ipv4/address)
sed -i “s/.ListenAddress./ListenAddress $PRIVATEIPV4 /g” /etc/ssh/sshd_config
ssh restart

Add a comment
admin87f7492443
By:
admin87f7492443

Related

can i run my own debian based OS on a droplet? Question Question
When will Debian 9 be avialable? Question Question

These answers are provided by our Community. If you find them useful, show some love by clicking the heart. If you run into issues leave a comment, or add your own answer to help others.

×
Submit an Answer
2 answers
jtittle1 January 27, 2017

@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.

Reply Report
admin87f7492443 January 28, 2017

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

Reply Report

Related

Looking for something else?

Ask a new question Search for more help