Subject: Re: RFC1933 IPv4 mapped address
To: None <>
From: Andrew Brown <>
List: tech-net
Date: 12/19/1999 23:16:38
>Well, standards are standards but I don't like to have it on by
>default as to me it doesn't follow the rule `of least suprise';
>It makes a bind on INET6 get fuzzy semantics, as application
>programmer you may think you're accepting only real INET6 connections
>but you have no way of telling whether you get IPv4 connections in
>disguise too.

if you're doing a bind to an INET6 socket and using an appropriately
sized sockaddr in the accept call, can't you just check the ipv6
address in the resulting sockaddr via the IN6_IS_ADDR_V4MAPPED() macro
(from rfc2133, and superceded by rfc2553)?

then your application could "know" that it got an ipv4 connection and
drop it.

|-----< "CODE WARRIOR" >-----|             * "ah!  i see you have the internet (Andrew Brown)                that goes *ping*!"       * "information is power -- share the wealth."