Re: host(1) problem with -6 option

[Matthew Seaman]

mdh wrote:

Howdy folks,
I'm having a little trouble understanding a problem that the `host`
command in RELENG_7_0 (very recent) is having. This is by and large
my first time working with IPv6, which I've been meaning to learn for
some time. First off, I've got my zone file configured to return a
AAAA record for x1.mydomain and named isn't complaining. However,
when I run `host -6 x1.mydomain`, host returns the following output:

([EMAIL PROTECTED]) [/etc/namedb]: host -6 x1.mydomain
/usr/src/lib/bind/isc/../../../contrib/bind9/lib/isc/unix/socket.c:1179: 
internal_send: ::ffff:127.0.0.1#53: Invalid argument
/usr/src/lib/bind/isc/../../../contrib/bind9/lib/isc/unix/socket.c:1179: 
internal_send: ::ffff:IP.IP.IP.8#53: Invalid argument
/usr/src/lib/bind/isc/../../../contrib/bind9/lib/isc/unix/socket.c:1179: 
internal_send: ::ffff:127.0.0.1#53: Invalid argument
/usr/src/lib/bind/isc/../../../contrib/bind9/lib/isc/unix/socket.c:1179: 
internal_send: ::ffff:IP.IP.IP.8#53: Invalid argument
;; connection timed out; no servers could be reached

It's the way resolv.conf works.  Consider this --


nameserver      ::1
nameserver      127.0.0.1

Which is all fine and dandy when told to use IPv6:

happy-idiot-talk:~:% host -6 h-i-t.infracaninophile.co.uk
h-i-t.infracaninophile.co.uk is an alias for 
happy-idiot-talk.infracaninophile.co.uk.
happy-idiot-talk.infracaninophile.co.uk has address 81.187.76.162
happy-idiot-talk.infracaninophile.co.uk has IPv6 address 
2001:8b0:151:1:240:5ff:fea5:8db7
happy-idiot-talk.infracaninophile.co.uk mail is handled by 10 
smtp.infracaninophile.co.uk.

but goes tits-up when told to use IPv4:

happy-idiot-talk:~:% host -4 h-i-t.infracaninophile.co.uk
host: couldn't get address for '::1': address family not supported

nameserver entries in resolv.conf are tried in the order given.  Using
the -4 or -6 switches to host(1) forces it to try each of the listed



Name: localhost
Address: 127.0.0.1#53

h-i-t.infracaninophile.co.uk is an alias for 
happy-idiot-talk.infracaninophile.co.uk.
happy-idiot-talk.infracaninophile.co.uk has address 81.187.76.162
happy-idiot-talk.infracaninophile.co.uk has IPv6 address 
2001:8b0:151:1:240:5ff:fea5:8db7
happy-idiot-talk.infracaninophile.co.uk mail is handled by 10 
smtp.infracaninophile.co.uk.


happy-idiot-talk:~:% host -6 h-i-t.infracaninophile.co.uk localhost
Using domain server:
Name: localhost
Address: ::1#53

h-i-t.infracaninophile.co.uk is an alias for 
happy-idiot-talk.infracaninophile.co.uk.
happy-idiot-talk.infracaninophile.co.uk has address 81.187.76.162
happy-idiot-talk.infracaninophile.co.uk has IPv6 address 
2001:8b0:151:1:240:5ff:fea5:8db7
happy-idiot-talk.infracaninophile.co.uk mail is handled by 10 
smtp.infracaninophile.co.uk.


Arguably it is a bug for host(1) to give up on the first entry in

everything works as expected.

        Cheers,

        Matthew

[*] but only if the domain name of the nameserver you want to query
can be resolved by means that don't  fall foul of the same IPv4 vs


--
Dr Matthew J Seaman MA, D.Phil.                   7 Priory Courtyard
                                                 Flat 3
PGP: http://www.infracaninophile.co.uk/pgpkey     Ramsgate
                                                 Kent, CT11 9PW

happy-idiot-talk:~:% cat /etc/resolv.conf domain infracaninophile.co.uk nameserver addresses by the stated protocol. It makes no sense at all to try and access an IPv6 address using IPv4 transport, and trying the converse: an IPv4 address via IPv6, will either fail or try and use IPv4-mapped addresses. You might think that the '-4' and '-6' flags to host(1) are pretty much useless in that case, but they work fine when you also tell host(1) the domain name of a nameserver to use[*]: happy-idiot-talk:~:% host -4 h-i-t.infracaninophile.co.uk localhost Using domain server: Aliases: Aliases: /etc/resolv.conf when told to use a conflicting address type. However, that should be reported to ISC rather than the FreeBSD project. When allowed to determine the transport type automatically IPv6 problem. Which boils down to using other than the DNS -- eg. /etc/hosts -- to find the nameserver address.

signature.asc
Description: OpenPGP digital signature