IPv4 and IPv6 address lengths

Little scum · Posted on 3/21/2019 5:12:16 PM

The binary form of IPv4 addresses is 32, and the maximum length is 15 in our commonly used dot decimal form, for example, "255.255.255.255"

Therefore, the maximum length of the IPv4 address string form defined in the <netinet/in.h> of posix is 16 bytes, and the '\0' terminator also needs to occupy 1 byte:

#define INET_ADDRSTRLEN 16

The binary form of IPv6 addresses is 128 long, and it is expressed in hexadecimal form such as "ffff:ffff:ffff:ffff", at first I thought that the maximum length of the IPv6 address string form was 128/4+7+1=40 bytes

However, looking at the IPv6 address string form defined in the <netinet/in.h> of posix, the maximum length is 46 bytes

#define INET6_ADDRSTRLEN 46

The IPv6 address originally mapped by IPv4 may have this format "ffff:ffff:ffff:ffff:255:255:255:255", which is 45 bytes, plus the closing character is 46 bytes

The blue smoke and moon shrouded the sand · Posted on 3/22/2019 4:12:49 PM

Prompt:Authors are banned or removed content is automatically blocked

IPv4 and IPv6 address lengths

Related Posts

Sections viewed

The blue smoke and moon shrouded the sand	Posted on 3/22/2019 4:12:49 PM \| Prompt:Authors are banned or removed content is automatically blocked
The blue smoke and moon shrouded the sand