The wiki DDNS Client guide didn't quite work for me with GratisDNS.
This is how I did it:
1: Install the "luci-app-ddns" application (and remember to enable it afterwards in web UI menu "System\Startup")
2: Add an entry in the file "/usr/lib/ddns/services":
"GratisDNS" https://ssl.gratisdns.dk/ddns.phtml?u=[USERNAME]&p=[PASSWORD]&d=Mydomain&h=[DOMAIN]&i=[IP]
Replace "Mydomain" with your own domain, e.g. e.g. "openwrt.com"
3: Add an DDNS entry in the file "/etc/config/ddns":
config service 'gratisdns'
option interface 'wan'
option use_syslog '1'
option use_https '1'
option force_interval '72'
option force_unit 'hours'
option check_interval '10'
option check_unit 'minutes'
option retry_interval '60'
option retry_unit 'seconds'
option enabled '1'
option service_name 'GratisDNS'
option domain 'YourHost'
option username 'YourUserName'
option password 'YourPassword'
option ip_source 'network'
option ip_network 'wan'
*Peplace "YourUserName", "YourPassword" and "YourHost" e.g. "ftp.openwrt.com"
4: Install the application "Curl" to enable SLL/HTTPS support
5: Install the application "ca-certificates"
6: Insert the following line into the file "/etc/profile":
export SSL_CERT_DIR=/etc/ssl/certs
7: Execute this command with SSH (PuTTY or WinSCP):
source /etc/profile
Done! :-)
(you might need to reboot)
To test the script use this command with SSH:
/usr/lib/ddns/dynamic_dns_updater.sh gratisdns
I get this result:
root@OpenWrt:~# /usr/lib/ddns/dynamic_dns_updater.sh gratisdns
update_url=https://ssl.gratisdns.dk/ddns.phtml?u=[USERNAME]&p=[PASSWORD]&d=wit.dk&h=[DOMAIN]&i=[IP]
force seconds = 259200
check seconds = 600
old process id (if it exists) = ""
time_since_update = 0 hours
Running IP check...
current system ip = xx.xx.83.207
registered domain ip = xx.xx.83.156
update necessary, performing update ...
updating with url="https://ssl.gratisdns.dk/ddns.phtml?u=XX&p=XXt&d=XX&h=XX&i=xx.xx.83.207"
% Total % Received % Xferd Average Speed Time Time Time Current
Dload Upload Total Spent Left Speed
100 6 100 6 0 0 9 0 --:--:-- --:--:-- --:--:-- 9
Update Output:
OK<br>
Good luck :-)