Re: lib/42405: libc: getaddrinfo() should perform T_A lookups before T_AAAA lookups, was: Resolver problems

[Thor Lancelot Simon <tls%panix.com@localhost>]

On Fri, Dec 04, 2009 at 11:37:26AM -0800, Jason Thorpe wrote:
> 
> Maybe we should ask for AAAA and A in parallel.  It would also be nice
> if all of this was transparent to libc.  IMO, all resolving activity
> should be done through mdnsd, and we can make policy tweaks there.

I think this is a very, very bad idea, because it is so inherently fragile.
To my knowledge, the first Unix system to take this approach was Irix.
I know of a number of sites which actually switched away from Irix in the
ensuing years because, of course, any problem with the name service caching
daemon brought the system quickly into an unusable state -- and there were
plenty of problems.

Similarly, I've seen nameservice cache daemon problems, at one point or
another, cause major issues with every version of OS X I've used (which is
all of them).

This is a valuable feature but in my opinion it should not be the default
and it should certainly not be the only way libc can do it.

Thor