Broken Routers And Disabling Ipv6

Now and then someone posts a query to the effect: I can access the Internet via my broadband router with Windows fine but not with Linux. I have always been puzzled why the common advice of disable IPv6 seems to work, as IPv6 should not affect IPv4.

Well, apparently it does, if you have a router with a broken DNS proxy, as shown here:

http://sourceforge.net/tracker/index.php?f...amp;atid=102283

You can test this as shown in the bug report:

$ dig @192.168.1.1 AAAA ubuntuusers.de
--> answer: 2001:780:0:25::80 (correct)
$ dig @192.168.1.1 A ubuntuusers.de
--> answer: 32.1.7.128 (wrong, should be 213.95.41.11)

You should replace 192.168.1.1 by the address of your router.

Aside from disabling IPv6 lookups, other workarounds include bypassing the router DNS proxy and using the ISP's forwarding DNS server. Another is to run your own DNS resolver (bind9) on your LAN.

Edit: A browse of several forums indicates that IPv6 DNS lookups (which actually happen over IPv4) can't be disabled globally. Disabling IPv6 modules only disables IPv6 traffic. So I don't know if that proposed workaround really works.