Using domain as hostname for ssh

September 24, 2019 322 views
API DNS Automated Setups

I’m currently writing a script using the REST API to automate the process of creating a droplet from a snapshot. I have my own domain for the snapshot (we’ll say it’s example.com) and in the script I map the new IP of the created droplet to sub.example.com through an A record. When using putty, I try to enter sub.example.com as the hostname and it gives me an error saying “hostname not found”. If I try and enter the assigned ip address to the droplet it works. Is there something else I need to do that I’m missing to get this to work? Thanks!

1 Answer

Hello, @QuantumPie

Have in mind that when you create an A record for the subdomain (sub.example.com) the DNS will need some time in order to propagate. This might take up to 48 hours in order to fully update due to ISPs (Internet Service Providers) cache on their end.

If the A is created shortly before you try to ssh using the subdomain as hostname, this will be the reason you’re getting the “hostname not found” error in putty.

Let me know if you have any questions.

  • Shoot. So If I’m getting new IPs every couple hours, there is no fessable way to do this?

    • Hey,

      to be honest it will work, but the DNS will always needs some time in order to ssh using the hostname. As mentioned the DNS might need 24 hours in order to complete, but usually happens a lot faster, especially if you put a lower TTL for the A record.

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