Message389556
Python supports IPv4-mapped IPv6 addresses as defined by RFC 4038:
"the IPv6 address ::FFFF:x.y.z.w represents the IPv4 address x.y.z.w.”
The current behavior is as follows:
from ipaddress import ip_address
addr = ip_address('::ffff:8.8.4.4') # IPv6Address('::ffff:808:404')
addr.ipv4_mapped # IPv4Address('8.8.4.4')
Note that the textual representation of the IPv6Address is *not* in IPv4-mapped format.
It prints ::ffff:808:404 instead of ::ffff:8.8.4.4.
This is technically correct, but it’s somewhat frustrating as it makes it harder to read IPv4s embedded in IPv6 addresses.
My proposal would be to check, in __str__, if an IPv6 is an IPv4-mapped, and to return the appropriate representation :
from ipaddress import ip_address
addr = ip_address('::ffff:8.8.4.4')
# Current behavior
str(addr) # '::ffff:808:404'
repr(addr) # IPv6Address('::ffff:808:404')
# Proposed behavior
str(addr) # '::ffff:8.8.4.4'
repr(addr) # IPv6Address('::ffff:8.8.4.4')
A few data points:
- Julia prints ::ffff:808:404 (current behavior)
- C (glibc) and ClickHouse prints ::ffff:8.8.4.4 (proposed behavior) |
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Date |
User |
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2021-03-26 17:34:40 | maxmouchet | set | recipients:
+ maxmouchet |
2021-03-26 17:34:40 | maxmouchet | set | messageid: <1616780080.54.0.443105360022.issue43633@roundup.psfhosted.org> |
2021-03-26 17:34:40 | maxmouchet | link | issue43633 messages |
2021-03-26 17:34:40 | maxmouchet | create | |
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