Create your own Dynamic DNS using files shared using an ftp account and a web hosting service
LICENSE Copyright 2014 Mark Hughes, http://markhughes.com.
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ftpdns is a hack... you need web hosting to:
- host a trivial PHP script
- provide an ftp server account
It is pure co-incidence that I operate a suitable UK based hosting service, at http://managedwebsitehosting.net
Each machine to be accessed remotely using the DNS runs a bash script that gets its public IP and uploads this and its hostname in a file to the ftp account. My machines Linux/Win7 run this script regularly using cron/scheduler.
I've written a short client script in perl that grabs the files from the ftp server and edits the local hosts file to insert entries for reach machine, while preserving the rest of the file.
On windows I have cygwin Perl installed.
Important thing is its simple, free and works. :-)
You will need a web hosting service (such as my UK based http://managedwebsitehosting.net - repeat shameless plug) where you can a) host a trivial PHP script, and b) create a password protected ftp account where these scripts can upload and access some small text files (one tiny file per remote machine).
Set up a password protected ftp account that will be used to store and access files containing DNS details.
Edit the following files and replace elements inside '<' and '>' (e.g. ) to refer to the web hosting and FTP services and account you are going to use.
ftpdnsputip.sh
ftpdnsmakehosts.pl
On Windows machines you might want the very simple wrappers for these files ftpdnsputip.bat and ftpdnsmakehosts.bat. All files need to be somewhere on the path, or if not, you can specify the full path whenever you run them (e.g. from command line, cron or Task Scheduler).
Ensure the ftp and scripts they refer to are in place as follows.
I suggest you upload a copy of the edited ftpdns files in a folder of this ftp account to make it easy to install the files on any machines featuring in or using ftpdns.
Upload getmyip.php to your web hosting service, accessible as http:///getmyip.php or similar.
On each remote machine you want to be accessible using this Dynamic DNS:
-
ftpdnsputip.sh (on Windows you might also want the wrapper ftpdnsputip.bat)
-
a suitable 'bash' shell (e.g. cygwin on Windows)
-
wget (e.g. cygwin on Windows)
-
a cron or Windows Task Scheduler job to run ftpdnsputip.sh automatically (e.g. every 15 minutes)
-
a standard ftp command line program (e.g. cygwin on Windows, or on Linux run: sudo apt-get install ftp)
-
commands and scripts need to be somewhere on the path, or if not, you can specify the full path whenever you run them (e.g. from command line, cron or Task Scheduler).
Note: these tested on Windows 7 and Ubuntu 14.04 LTS
On each machine you want to be able to access the remote machines you need:
-
ftpdnsmakehosts.pl (on Windows you might also want the wrapper ftpdnsmakehosts.bat)
-
a suitable Perl interpreter (e.g. cygwin on Windows)
-
a standard ftp command line program (e.g. cygwin on Windows, or on Linux run: sudo apt-get install ftp)
-
commands and scripts need to be somewhere on the path, or if not, you can specify the full path whenever you run them (e.g. from command line, cron or Task Scheduler).
Note: these tested only on Windows 7
Sorry for requiring Perl and bash, but I decided to use Perl 'after' I wrote the bash script. Feel free to convert ftpdnsputip.sh to Perl!
Its fine for a machine to act in both roles at once.
-
Inserting your web hostname, check that you can manually obtain a "somename.getmyip" file with:
wget -qO somename.getmyip http:///getmyip.php >/dev/null
-
Check the content of the somename.getmyip file looks like a valid "hosts" file entry, for example:
12.45.56.78 somename
You can access the http:///getmyip.php in a web browser to verify this.
- Use command line ftp to verify the machine can login to ftp, and then UPLOAD the "somename.getmyip" file from step 1)
-
Use command line ftp to verify the machine can login to ftp, and then DOWNLOAD a previously uploaded "somename.getmyip" file.
-
Check you can repeat the effect of 1), 2) and 3) using ftpdnsputip.sh
-
From the directory containing your hosts file (/etc on Linux, C:\Windows\system32\drivers\etc\ on Windows 7), make a backup copy of your hosts file. Then manually run ftpdnsmakehosts.pl, for example using:
On Windows you will need Administrator permissions
c:\cygwin\bin\perl /cygdrive/c/binl/ftpdnsmakehosts.pl
On Linux you will need to use "sudo" when running manually, or run the script using the root crontab, because it needs to edit the "hosts" file.
The above is to verify that it downloads all *.getmyip files stored on the ftp server and inserts an entry for each in the hosts file (while preserving everything else). Repeating the command will just update the inserted section which will look something like this:
98.19.245.34 tantalum
23.87.237.52 bargee
-
Try "ping tantalum" etc to verify you machine picks this up. On Windows I provide a wrapper (ftpdnsmakehosts.bat) that runs the command followed by "ipconfig /flushdns" although this does not seem to be necessary.
-
Once you have set up cron (Linux) or Task Scheduler (Windows) jobs to run the ftpdnsputip.sh script regularly, verify that it does indeed update the files on the ftp server whenever those machines are on.