Remote access using openssh and DynDNS

I’m not a big fan of the “cloud” and having to rely on third party to store and sync my data. I prefer to have more control of my own things. Unfortunately static IP address are usually paid and not very cheap. I don’t want to pay for a static IP adress right now so U looked for other options. DynDNS seemed to be the best one. What does it do? Well, it takes your public dynamic IP adreess provided by your IPS and associates that with a domain name DynDNS provides. But if its a dynamic DNS won’t it change and break your connection anyway? That’s where ddclient come… but one thing at a time so I don’t get lost with the instruccions.

This assumes you already have ssh configured and a static IP adress assigned to your computer that will be the server your want to connect to. There are lots of guides online on how to do this.

1- Sign up to DynDNS dynaic DNS service. It’s free and reliable! The confirmation email can take some hours to arrive, mine took around 4 or 5 hours, so be patient.

2- Choose your domain name from the free ones DynDNS provides. There are a lot of options, some of them very cool such as :). Take note of your username and password and domain name. They will be needed again.

3- Configure your rooter to foward port 22 (for ssh)  to your computer (the server one). If you dont know how to do this follow a guide to your router at:

4- Install ddclient (it’s in Debian/Ubuntu Repositories) and debconf will popup aking you to configure the client. Select DynDNS as the service provider and enter your username and password. ddclient will update with DynDNS your public IP address so that the connection is not broken when the public IP address changes. It can be done trough the router but apparently doing this thought software is more reliable.

This is a sample /etc/ddclient.conf file to update Dyndns:

# Configuration file for ddclient generated by debconf
# /etc/ddclient.conf




use=web,, web-skip=’IP Address’






5 – See if it works! Example: ssh If it does not work when you have booth computers at your LAN, try a remote access, some routers don’t support loopback connections.

For security reasons make sure you have ssh configured to allow key acess only. Password autentication over the internet is not safe really. Follow these guides on how to setup openssh and openssh with key acess.

13 comentários a “Remote access using openssh and DynDNS”

  1. Do you have user name(s) and password(s)? WHOIS Information Who is the registrant? Can you access the administrative email address? Is the domain name locked? Where the domain name is registered at?

  2. HTML 5 allows connections across domains, through use of the Access- Control HTTP header, as defined in a separate W3C specification (which applies identically to normal XHR usage and to server- sent events). A request is made for a resource as usual, but if that resource on the server (in this case, an event stream from a Comet server), includes the Access- Control HTTP header with values allowing the use of the resources, browsers will treat it as if it came from the same domain as the main document. If…

  3. @T-Rex your comments are… well, confusing and they considered as spam by askimet 😛

    I am tented to considerer it also as spam, but you seem to have a valid email adress and a website. Anyway I don’t get your comments 🙂

  4. I’ve been trying to get this to work myself. I believe port forwarding is working (it’s working for other services), and ddclient is working, and I can ssh on the LAN to my server.

    But when I try to come from the Internet (using PuTTY), it prompts for “”. This fails, i think because my server’s expecting to authenticate “user@localhostname” ?

    So this is probably a dumb question: how to get ssh and/or putty to authenticate as my server’s local user, when coming from outside?

  5. @Michael: “” should work. Make sure your firewall is not blocking port 22 (if you didn’t change the default ssh’s port).

  6. yep, works, i’m a dummy. i tried from *outside* as you suggested in the article. guess my router is one of those that don’t do lookback connections.

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