Bug#684794: getaddrinfo sorts IPv4 before IPv6

[Bastian Blank <waldi@debian.org>]

On Mon, Aug 13, 2012 at 10:54:28PM +0200, Per Olofsson wrote:
> I recently configured IPv6 connectivity on my system using 6to4 on my
> router. It works, except that getaddrinfo() sorts IPv4 addresses
> before IPv6 addresses, which means that IPv4 is used if the remote
> host has both IPv4 and IPv6.

This is expected behaviour if you are using 2002::/16 addresses:

|    Rule 7:  Prefer native transport.
|    If DA is reached via an encapsulating transition mechanism (e.g.,
|    IPv6 in IPv4) and DB is not, then prefer DB.  Similarly, if DB
|    is reached via encapsulation and DA is not, then prefer DA.

> $ getent ahosts www.debian.org
> 86.59.118.148   STREAM www.debian.org
> 86.59.118.148   DGRAM  
> 86.59.118.148   RAW    
> 2001:858:2:2:214:22ff:fe0d:7717 STREAM 
> 2001:858:2:2:214:22ff:fe0d:7717 DGRAM  
> 2001:858:2:2:214:22ff:fe0d:7717 RAW

| $ getent ahosts www.debian.org
| 2001:858:2:2:214:22ff:fe0d:7717 STREAM www.debian.org
| 2001:858:2:2:214:22ff:fe0d:7717 DGRAM  
| 2001:858:2:2:214:22ff:fe0d:7717 RAW    
| 86.59.118.148   STREAM 
| 86.59.118.148   DGRAM  
| 86.59.118.148   RAW    

Bastian

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