I am wondering how, on a technical level, IPv4s and domains can be distinguished.
An IPv4 takes the form [0-255].[0-255].[0-255].[0-255].
A domain takes the form (a)+.b, where (a)+ denotes that this string occurs at least once and may repeat.
The values of a can be considered arbitrary alphanumericals (so yeah, mathematically, I am not super correct with the expression above), as can the values of b, though b has practically more restrictions because it must usually be registerd Top Level Domain (TLD), but apart from that, may be arbitrary alphanumericals, either.
In theory, the set of ip addresses looks like a subset of the set of domain addresses.
Edge cases like special characters and special addresses are not relevant for this question and can be ignored.
When I enter an IP or domain into my browser address field, the terminal, or an application, how does the system know whether I entered a domain that requires resolution, or an IP address that can be directly contacted?
Can someone, on a technical level, explain how the system handles these strings and what possible interactions can occur and whether (and why) this raises security issues, or not?
I was wondering, whether an attacker would be able to exploit this ambiguity and whether there are cases where exactly this already happened in the past.
