> ::ffff:0:0:0/96 == ::ffff:0:a.b.c.d https://www.ibm.com/docs/en/zos/2.1.0?topic=addresses-ipv4-mapped-ipv6
Mapped IPv4 addresses have the ::ffff:a.b.c.d short form, without any intervening 0 word. The CIDR form above just denotes that 96 bits are the prefix (the "network" part) and, thus, the remaining 32 bits is the host part within the network. IPv6 addresses are 128 bit long. But the ::ffff:0:a.b.c.d notation is not a mapped IPv4 address, it's just some IPv6 address which is written with last four octets in the IPv4 notation (any IPv6 address can be accepted this way), but when you convert it back from its binary form, that won't re-emerge the same way because only IPv4 compatible (all 96 leading bits zero) or IPv4 mapped (80 zero bits followed by 16 one bits) followed by 4 bytes of IPv4 address) can be conventionally written in the IPv4 form (depending on the system settings). E.g. 1.2.3.4 (input) -> (binary rep) ::ffff:1.2.3.4 -> (output) 1.2.3.4 but ::ffff:0:1.2.3.4 -> (binary rep, same) -> (output) ::ffff:0:102:304 HTH, Anton Lavrentiev Contractor NIH/NLM/NCBI -- Problem reports: https://cygwin.com/problems.html FAQ: https://cygwin.com/faq/ Documentation: https://cygwin.com/docs.html Unsubscribe info: https://cygwin.com/ml/#unsubscribe-simple
