[Dnsmasq-discuss] local AAAA requests

Curby curby.public at gmail.com
Tue Mar 14 11:36:47 GMT 2006


Some of the requests I'm getting from other computers on my network
are AAAA requests.  Originally, my /etc/hosts file did not have any
IPv6 definitions, so such requests were logged as

Mar 13 06:02:01 www dnsmasq[3741]: config www is <NODATA>-IPv6

I then changed my hosts file as follows:

# For each entry like
    192.168.1.10  www.curby.net www
# I added something like
    ::ffff:c0a8:010a   www.curby.net www

This was just a guess, according to Section 2.5.4 of
http://www.ietf.org/rfc/rfc2373.txt

Then I started seeing log lines like:

Mar 14 03:42:01 www dnsmasq[4971]: query[AAAA] www.curby.net from 192.168.1.1
Mar 14 03:42:01 www dnsmasq[4971]: /etc/hosts www.curby.net is
::ffff:192.168.1.10
Mar 14 03:42:01 www dnsmasq[4971]: query[A] www.curby.net from 192.168.1.1
Mar 14 03:42:01 www dnsmasq[4971]: /etc/hosts www.curby.net is 192.168.1.10

which might be explained by the fact that ffff at the beginning of the
embedded IPv4 address means the host doesn't support IPv6, so the
client requests an IPv4 address.  Alternately, the host is sending
both IPv4 and IPv6 requests at the same time.  (Do you have any idea
if Linux (Debian 3.1) would do this?)

I'm starting to think I'm in over my head though, so I'd like to ask
here how local IPv6 AAAA requests are supposed to be handled.  I would
prefer that all requests that should be handled by /etc/hosts (namely
local machines) get handled and logged that way and for DNS traffic in
my network to be minimized.  Ideally, if I receive an IPv6 request, I
should be able to reply, and that reply should be able to satisfy the
client so it doesn't need to send another request. (As noted above
however, some clients seem to blast both IPv4 and IPv6 requests at
once.)

So... is there any way for dnsmasq to intelligently map IPv4 addresses
to IPv6 addresses if an IPv6 address isn't explicitly defined? 
Alternately, can/should I disable the ability to service IPv6 requests
(I'm guessing that I shouldn't)?  Alternately, what is the correct way
to specify an IPv6 address in /etc/hosts so a DNS client can actaully
make use of the reply?

    ::0000:[ipv4 address]
    ::ffff:[ipv4 address]
    fe80::[something, but how would I determine this?]
    something else?

I know that inexperience often leads to the inability to clearly
phrase a question, so please ask for more information if it's needed. 
My config follows:

# dnsmasq.conf, stripped
    domain-needed
    bogus-priv
    strict-order
    expand-hosts
    domain=curby.net
    cache-size=500
    log-queries
    conf-file=/etc/dnsmasq.adservers.conf

Thanks!

--Curby



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