Register for a remote access dynamic dns account from dyndns.org and add hostname in My Hosts menu
Then configure it on your stc 4g router
Example:- if you added host as sample.dyndns.org
Domain name: dyndns.org
Hostname: sample
Username: your username
Password: your password
select enable -> Submit
Now the private ip will be updated to dyndns server.
You can only access STC 4g router from another STC 4g router