Maximum length of the textual representation of an IPv6 address?

Question

I want to store the data returned by $_SERVER["REMOTE_ADDR"] in PHP into a DB field, pretty simple task, really. The problem is that I can't find any proper information about the maximum length of the textual representation of an IPv6 address, which is what a webserver provides through $_SERVER["REMOTE_ADDR"].

I'm not interested in converting the textual representation into the 128 bits the address is usually encoded in, I just want to know how many characters maximum are needed to store any IPv6 address returned by $_SERVER["REMOTE_ADDR"].

Answer 1

Answered my own question:

IPv6 addresses are normally written as eight groups of four hexadecimal digits, where each group is separated by a colon (:).

So that's 39 characters max.

Answer 2

I believe it would be:

8 * 4 + 7 = 39

8 groups of 4 digits with 7 ':' between them.

Or, if you want to take into account the IPv4 tunneling features [0000:0000:0000:0000:0000:0000:192.168.0.1],

(6 * 4 + 5) + 1 + (4 * 3 + 3) = 29 + 1 + 15 = 45