[clug] For dyndns junkies

Bob Edwards bob at cs.anu.edu.au
Tue Aug 22 00:34:44 UTC 2017

On 21/08/17 20:10, Andrew Janke via linux wrote:
> #! /bin/sh
> IP=$(wget -O - http://icanhazip.com/ -o /dev/null)
> So many good things available out there that I am yet to find.  This
> one courtesy of:
>    https://github.com/AntonioCS/no-ip.com-bash-updater.git
> a

I'd just say be careful - transparent proxying and NAT means that
the IP(v4) address that an HTTP service sees may well be quite different
than what some other protocol might see, or the IP(v4) that you
are using to offer public-facing services.

I had a colleague trying to SSH to a server I maintain from an
ISP-connected machine in Singapore. He gave me his IP(v4) address
which he found from a web-based service so that I could allow it
for SSH access.

The IP(v4) that his SSH was using was completely different. I had to
convince him to SSH into another server and type:
which revealed the actual (probably NAT'd) IP(v4) he was using.


Bob Edwards.

More information about the linux mailing list