Custom Domain Validation Checking

[Aqiszz]

Hello 
I am creating a custom registrar module, and I want to add validation for domain names that should be invalid when using special characters like %tesdomain&.xyz. This work for the following examples:

• -tesdomain.xyz
• tesdomain-.xyz
• -tesdomain-.xyz
• na--domain.my.id
  
  All the example above should return an error "the domain is invalid".

I have tried using the DomainValidation hook, but it seems the domain name is already sanitized from special characters, so I think I cannot use this method. Do you have any ideas on how to perform this validation?
now i am using whmcs namespinning as the lookup provider

[RadWebHosting]

Why not query the registry's WHOIS? It seems you'd need to get the availability value...

[Aqiszz]

Quote

Why not query the registry's WHOIS? It seems you'd need to get the availability value...

No, I don't have any issues with getting the availability value. I just want to add additional validation outside of the validation done by WHMCS. For example, when I enter a domain name like $tesdomain%, it gets detected as 'tesdomain' and it's considered available (if available). What I mean is that I want to add validation for domains that contain special characters.