Joel Wiramu Pauling wrote:
I presume this is probably firmware specific. Have you tested with
various
firmwares to confirm the problem?
I suspect not. This problem would explain some very bizarre DNS problems I've experienced at home when using IPv6, with another DSL box from the same vendor, not used with Xtra.
I never diagnosed it, but I bypassed it by disabling use of the resolver in the CPE and going straight to the ISP's resolver.
I believe they are all using dnsmasq as the resolver, and old 2.4 linux
kernels for network stack. It would not surprise me if the root lies in one or the other.
In either case I am fairly certain a customised firmware would solve the problem. Alternatively, just disable dns relay in dnsmasq on the router and hardcore an upstream one as you suggested.
It's a well known bug in dproxy-nexgen. It doesn't understand AAAA replies and corrupts them.[1] So since things do a AAAA query first, they get a response, which dproxy corrupts, and then caches. Then the follow up A query gets served out of the cache as 1.0.0.0 (or depending on what the reply was, potentially some other address). dproxy appears to be unmaintained since about 2004, but appears that it was added to the firmware of many (slightly older) embedded devices. There are many many reports around the Internet of people failing to resolve things (and then getting confused when "ping" works -- because ping is v4 only, it doesn't do the v6 query first) and many people hitting on the solution of "disabling IPv6", and reporting it upstream as a v6 bug in which ever piece of software they were using at the time they noticed the problem, few people seem to realise it's their ADSL modem, and only a couple have tracked it back to the particular software on the modem itself. There are also many people suggesting you hard code DNS servers (usually OpenDNS servers) to bypass the broken devices resolver. I had assumed that most of these devices had managed to reach their end of life one way or another, but it's quite possible that there are still a very large number of these devices around. [1]: http://sourceforge.net/tracker/index.php?func=detail&aid=1925234&group_id=2283&atid=102283