Rule type: Reverse DNS

[zepich]

We would add a new rule type called Reverse DNS for this idea. With this rule type, it would be possible to register domains that are not allowed to submit a form.

Example:

• The client has the following IP address: 127.0.0.1
• The reverse DNS for this IP address is ip.127-0-01.internetprovider.xyz
• The domain of the internet provider internetprovider.xyz is added to a rule with the rule type Reverse DNS

When a client tries to submit a form with the IP address 127.0.0.1, mosparo resolves the DNS and receives the internet provider's domain. mosparo can then block the submission.

This rule type works differently than the Provider rule type since the Provider rule type requires the GeoIP2 database, which could contain outdated information. The Reverse DNS can be more accurate in detecting a specific provider.