issue getting response from some gtld servers

[JINMEI Tatuya / 神明達哉]

>>>>> On Fri, 12 Nov 2004 08:04:42 -0600, 
>>>>> Will Yardley <&- at no.spam.veggiechinese.net> said:

>>> aura% dig @a.gtld-servers.net net. soa
>>> 
>>> ; <<>> DiG 9.2.3rc3 <<>> @a.gtld-servers.net net. soa
>>> ;; global options:  printcmd
>>> ;; connection timed out; no servers could be reached
>> 
>> a.gtld-servers (as well as B) now has an IPv6 address. Your IPv6
>> routing seems down.
>> 
>> With a recent dig (> 9.2 ?), you can use the -4 option to force
>> IPv4. Or you can either fix IPv6 or disable it.

> Gah. I guess this is the cause of some of my weird hangs in Mozilla too.

As far as I know, this is not really correct.  The problem with dig
(< 9.3) is that it only tries the first address of the specified
nameserver name (in this case the IPv6 address).  Mozilla should be
able to try all possible addresses, but there are still know cases
which can cause wired results.  If you can provide more details
(including operating system and its version, the web site(s) that
caused the trouble), we may be able to help you.

> Doing a quick google, it would seem that on FreeBSD, setting:
> net.inet6.ip6.v6only to 0 /should/ resolve this problem (by checking the
> ip4 IP first), but doesn't seem to fix it for me. I have no intention of
> having an IPv6 connection on any of these machines any time soon, but it
> seems a bit annoying to have to completely remove ipv6 support just to
> "fix" this.

Setting net.inet6.ip6.v6only to 0 does not mean "checking IPv4
addresses first", but it can help some situations.  I suspect you just
encountered other cases where "v6only=0" doesn't help.

> I guess putting "-4" in .digrc will do the trick.

> A bit OT for this forum, but do I have any options on FreeBSD or OpenBSD
> other than rebuilding the kernel / OS without ipv6 support?

If you're using FreeBSD 5.3 (or perhaps other 5.x - I'm not 100%
sure), you might want to try:

- create a file containing the following lines:
::1/128               50     0 
::ffff:0:0/96         45     4
::/0                  40     1 
2002::/16             30     2 
::/96                 20     3 

- execute the following command as a super user:
# /usr/sbin/ip6addrctl install FILENAME

This way you can tell some DNS resolver routines about your preference
between IPv4 and IPv6.  My firefox 1.0 on FreeBSD 5.3R works well with
this.

					JINMEI, Tatuya
					Communication Platform Lab.
					Corporate R&D Center, Toshiba Corp.
					jinmei at isl.rdc.toshiba.co.jp