inadyn is a C based client used to update DNS entries. Inadyn is an IP update client for DynDNS.com, no-ip.com , etc.

Why we need this? Well you don’t really need this if you are using static IP.

But if you have dynamic IP, you must keep your IP updated with the domain you choose in DynDNS.com or no-ip.com  every time you restart the router. Otherwise, the visitors can’t reach to your server.

Installation:

apt-get update && apt-get install inadyn

or you can download inadyn:

cd /usr/src


wget http://cdn.dyndns.com/inadyn.zip

unzip inadyn.zip

cp inadyn/bin/linux/inadyn /usr/bin/inadyn

Change the file permission:

chmod 755 /usr/bin/inadyn

Configuration file for inadyn:

vim /etc/inadyn.conf

In the inadyn.conf file must look something like as shown below:

## inadyn configuration file

# Check for a new IP every 600 seconds
update_period_sec 600

# How often the IP should be updated even if it is not changed
#forced_update_period 600 (not recomended to be used)

# DynDNS username and password here
username your-username
password your-password

#An optional DNS service. For http://www.dyndns.org the acceptable services are one of dyndns@dyndns.org, statdns@dyndns.org.
dyndns_system dyndns@dyndns.org

## Dynamic DNS hosts
#A host name alias.
alias your-choice.dyndns.info …etc

#run in background
background
#The name, including the full path, of a log file.
log_file /var/log/inadyn.log

Now set inadyn to start every time the system rebooted:

crontab -e

In the crontab, add this:

@reboot inadyn