TransIP DynamicDNS

A few weeks ago I spotted an interesting deal to have my own domain name (fritvet.be). I decided to register it and forward it to my external IP address.

Now the problem was that my isp doesn't assign static IP addresses, so I had to update my domain DNS settings regulary to keep it forwarded to my actual external IP address.

In order to do this, my DNS registrar ( TransIP ) provides an API built in PHP which allows to update the DNS settings for my domain.

Though my knowledge of PHP is next to nonexisting, I managed to get a setup running in a FreeNAS jail which will be explained in this blogpost.

Overview

1. Creating a FreeNAS jail + general configuration
2. install php & php-extensions
3. script for execution + crontab

Maybe some additional information about my setup which might be relevant:
- This installation was done on FreeNAS 9.2.1.3-RELEAS-x64
- forumpost on transip which contains a working php script: click!

1. Creating a FreeNAS jail + general configuration

Start off by logging into the FreeNAS webinterface and navigate to jails and choose to add a jail.
Enter a suitable jailname, make sure to select standardjail as type, and fill in an IP address in the same range as the subnet where the FreeNAS server is located in.

property	value
Jailname	TransIP-PRD
IPv4 address	192.168.1.110
type	standard
vanilla	FALSE (unchecked)

Once the jail is created, open a terminal session on the newly created jail via the FreeNAS web interface so that SSH can be enabled.

Configure root password

The root password can be set by executing the following command
passwd root

Create technical user account

The technical user account will be used to run the script.
run the adduser command to create a new user:

Note that the user is also added to the group wheel so that during a session, the user can switch user as root if necessary. At the end of the configuration, the account will be removed from the group so that root access will be denied.

Enable SSH

modify the file /etc/rc.conf so that sshd_enable="NO" becomes sshd_enable="YES". This will make sure the sshd daemon will be start when the jail is started:
ee /etc/rc.conf

Now, the SSH daemon isn't running yet, execute the following command to start the sshd daemon:
service sshd start

Setting the hostname

Setting the hostname for the jail should be done so that it gets a nice name, issue this by executing the following command
hostname transip-prd.local

Portstree

Now that ssh is set up and a technical user account (transip) is created, further configuration can be done via a SSH session. Once logged in via ssh, run the following commands to pull and extract the portstree in the jail :
portsnap fetch extract

Note: Only the first time portsnap fetch extract should be used. If the portstree is already extracted, it can be updated in the future by executing portsnap fetch update

2. Install php and php-extensions

After the portstree is available inside the jail (default location is /usr/ports), the necessary software can be installed.
Since  the API is written in php, the php port should be installed inside the jail, this is done by executing the following commands as root:
cd /usr/ports/lang/php56
make install clean

After the sourcecode is downloaded and compiled, the program will be available: man php

The API also requires some php-extensions to be installed:
cd /usr/ports/lang/php56-extensions
make config

php56-extensions to be installed (1)

php56-extensions to be installed (2)

Moving the API to the jail

The API should be placed inside the jail so that it can actually be used. There are different ways of doing this, depending on your setup. I did this myself by downloading the API to my PC-BSD machine and with the help of the scp command the file could be copied to the jail (ssh should be running on the server for this method to work!)
Notice that the scp command was run on my PC-BSD machine.
scp transip.tar transip@192.168.1.110:/home/transip

after the file  was copied to the jail, it can be extracted with the following command:
tar -xf transip.tar

PHP script

In order to have a working php script, follow the instructions provided in the commented section of the php script - TransIP-updateDNS

3. script for execution + crontab

Fix group membership

Earlier on in this blog, the transip user was created and added to the wheel group, which allows the user to switch user to root. Now all configuration is done, the user can be removed from the 'wheel' group to improve the security
pw groupmod wheel -d transip

Shell script

A shell script provides the possibility of having multiple commands being run sequential. The following code will check if there is a directory called 'log'. If not, it will be created in /home/transip/updateDNS. Then, the current date and timestamp will be shown, and the actual php script which handles the DNS update is launched.

#!/bin/sh
cd /home/transip/updateDNS
if [ ! -d log ]; then
echo "creating log folder"
mkdir log
fi
date "+%d/%m/%Y - %H:%M"
/usr/local/bin/php /home/transip/updateDNS/update.php
printf "\n"

Make the script executable by executing chmod o+x shell.sh
If the script runs fine, you will see the following output (make sure to run this command as the transip to verify permissions are OK):

The shell script runs just fine, without any errors (permissions, php plugins missing,... ). The script should now be run on a fixed interval to keep the domain forwarded to my actual external IP.

Crontab

The crontab file allows us to configure scheduled tasks. In my case, I'll be running the 'update.sh' script each 15 minutes. The script should be run as the transip user, so make sure the following command is ran as the transip user.

crontab -e
and add the following line

*/15 * * * * /bin/sh /home/transip/updateDNS/update.sh >> /home/transip/updateDNS/log/updateDNS.log