Comment 11 for bug 369008

Debugging the case of scope ID == 0 when family is set to AF_INET6...

I'm finding that when family is set to AF_INET6, then _nss_gethostbyname2_r is called instead of _nss_gethostbyname4_r. This decision is made by libresolv. I did 'apt-get source libc6', which got me eglib-2.17 source (this is on Ubuntu 13.10 at the moment). In sysdeps/posix/getaddrinfo.c, I indeed see that it's only calling _nss_gethostbyname4_r when family is set to AF_UNSPEC. A comment says "gethostbyname4_r sends out parallel A and AAAA queries and is thus only suitable for PF_UNSPEC."

So that looks like a clash of requirements:

a) _nss_gethostbyname4_r is needed for IPv6 scope ID
b) _nss_gethostbyname4_r is allegedly not suitable for IPv6-only queries, because it sends out parallel A and AAAA queries.

Surely _nss_gethostbyname4_r SHOULD be used in order to get IPv6 scope ID.

What should we do next?