Today I found one of my website fully being displayed at another domain that is not mine. Is this some kind of DNS hack or what is the purpose of these actions ? Because I seen this before, few years ago, all content from Adobe Exchange (user uploaded content) was being displayed at many other domains.
Should I be worried about anything ?
Edit: I pinged that domain and it shows same IP address as my own domain. My site is a new/small social networking site with a bit under 3000 users. I found this other domain while looking at traffic sources.
Edit: The other domain that shows my site is forum.[domain].com and their main domain shows illegal downloads, it also has 20 000 Alexa traffic rank.
Temporary I made a test in my php scripts and if http_host is different than my domain, then it exists, this seems to work, but I probably need to edit some DNS settings to stop it from serving my site to outside domains. How do I do that ?
Edit: Inside Plesk panel under ip addresses
I removed the default domain
for that IP and this caused that other site to show a default Plesk panel (same page that is shown if someone directly types my IP in browser.