Update : whmcs is smart enough.
They use auto provision to validate license.
If you have installed WHMCS on hostgator Dedicated Server , Dedicated Hosting you will be able to use use WHMCS license as long you have hostgator dedicated hosting/server.
Once you install on any other hosting provider/ vps or even shared hosting of hostgator.
They will suspend your account…
Tip : if someone has real Dedicated server / hosting with hostgator & they are kind enough allow you to host a subdomain on his server you can use WHMCS .
How : ask him to host your subdomain on his hostgator server and keep this record for ever.
E.G : you will install whmcs on eg.bestblackforum.com so hostgator friend has to point www.eg.bestblackforum.com to hostgator.
Install whmcs on eg.bestblackforum.com -
After installing go to settings and change domain ( open settings in 2 tabs and also open whmcs license info page in tab 3.
In tab 2 change domain (whmcs installed domain to www.eg.bestblackforum.com , save ( it will shown error after saving) close tab 2.
In tab 3 pn license information click on force recheck.
Wait for a minute.
Go to tab 1 - change back domain to e.g.bestblackforum.com and save .
Now in file manager . Change license.php file permession to 644 (it is by default)
If above step fails ??
Open license info page and leave it open
Open PHP my admin - config (find where domain table is -/: edit table .
Change Default vlaue to : As Defined and in text feild enter subdomain www.eg.bestblackforum.com /
Now force reload license in tab you open in 1st step.
Additionally you can preven whmcs to verify your ip again & again .
By blocking whmcs license + whmcs IP in .htaccess
Let me know if you need my help