SSH on dynamic IP

ogromnakarina · 09-23-2011, 04:38 AM

Is it possible for me to ssh to my laptop at dormitory, which forbids me from having a static IP. If so, how?

claudelepoisson · 09-23-2011, 04:51 AM

Hi, you are looking for a dynamic DNS. Most people use dyndns.com. You can have an update client which detects and reports your IP to the DNS and allows you to access your box with <nickname>.homeip.net for example. The update client can be a linux program running on your machine. Most routers usually have an embedded update client but they suck unless you flashed your router with dd-wrt.

claudelepoisson · 09-23-2011, 04:57 AM

Here is an update because I couldn't include URLs in my first post (anti-spam policy).
DynDNS recommends these two linux update clients.
The free account at dynDNS is a little hard to find : http://dyn.com/dns/dyndns-free/.

ogromnakarina · 09-23-2011, 05:46 AM

Thank you, I will try this as soon as I get home.

BjarniRunar · 09-23-2011, 05:52 AM

Note that if you happen to be behind a strict firewall or NAT, dynamic DNS may not work.

In that case you will need a tunnel of some sort. If you have an external server somewhere you can put one together yourself using SSH and port forwarding, or alternately you can try a service like PageKite.

Googling for "ssh tunnel" or "PageKite SSH" will get you the docs you need in either case. :-)

- Bjarni

jefro · 09-23-2011, 04:48 PM

If the dorm is smart they'd block all of that but it seems that the technical staff at these places stink. So it should be typically easy.

Might see if you can get an old copy of barracudaserver to use https and you'd have to follow a dynamic dns setup. There are a few free choices out there.