Had some time today to have a proper look at why my MWEB ADSL service has been so bad and unreliable the last couple of days.
I'm running a Mikrotik Router PC as my boundary and the PPPoE session from this machine to a Dlink ADSL modem. Uncapped 4Mbps from MWEB.
Today nothing worked. Sites would not open, but the old clue SKYPE was working.
For those that do not know, when Skype is working, and nothing else,you have a DNS problem of some sort.
The problem this time was IPv6.
As part of the debugging I did a nslookup for www.microsoft.com on one of my Windows 7 machines and to my surprise it returned a IPv6 address. I have not deployed IPv6 on my home network yet, so this is a problem.
It seems that Mikrotik ROS 5 now includes IPv6 by default. Also Windows 7 has IPv6 by default, so wheels now you can come off.
I disabled the IPv6 module on the ROS and W7 and all is now working again.
Hope this helps someone.