[Q] How can I convert a variable of IPAddress class to a String Object?

Why do you think you need to? An IP address is simply 4 bytes. Convert them one at a time to a string, and then append the strings.

Maybe u can resolve it with a simple cast... for example int a;String b; b = a.toString();

for example int a;String b; b = a.toString();

Well, sure. If int was a class that had a toString() method. The Arduino is NOT programmed with C#.

PaulS:
Why do you think you need to? An IP address is simply 4 bytes. Convert them one at a time to a string, and then append the strings.

Yeah I think I will have to do something like that.. Thanks!