# Finding "lost" computers on the web the homebrew way #
*Jan 23, 2012*

During the course of updating my home computer I rebooted it because of a kernel update.  Later that week at work I went to connect to my home computer and discovered that it's dynamic IP had changed and it's DNS name was invalid.

So following common advice to "fix a problem two ways to prevent it in the future" I fixed the DNS, but I also wanted an automated way to track my computers when and if their IPs changed.

So the first thing I needed was shared place to store the IP information.  Thinking about it I realized that Dropbox would work well for that.  So all I needed was a simple script.

So the solution was to put a script that determined the IP of the computer in Dropbox and have cron on all the computers run it.  Each user can call cron with

    $ crontab -e

And I created a crontab directory that I could add more scripts to later if need be with and run them hourly with the following entry

    0 * * * * cd /home/dan && run-parts Dropbox/cron

The script itself was a file called `getip` and it used whatsmyip.com's automation detection script.

**getip**

    #!/bin/sh 
    
    wget -O /tmp/`hostname`.ip http://automation.whatismyip.com/n09230945.asp
    tmp_file=/tmp/`hostname`.ip
    dst_file=Dropbox/var/log/`hostname`.ip
    if ! diff -q ${tmp_file} ${dst_file} > /dev/null  ; then
      `cp ${tmp_file}  ${dst_file}`
    fi


Then I just created `Dropbox/var/log` and installed the crontab on all my computers, and volia, homebrew IP tracking for all my compters accessible to me from anywhere.

## Comments ##

**garza** Says:

January 25th, 2012

or just use gnudip?


** Dan Ballard** Says:

January 27th, 2012

@garza Assuming you have a server to run it from, which while I do, not everyone may, and in this case, this with dropbox and whatismyip replaces.