Source: http://oramossoracle.blogspot.com/ link : http://www.oramoss.com/blog/2008/08/fedora-9-on-hyper-v-on-windows-2008.html
I’ve been playing with Hyper V this week and came across an issue with Firefox, whereby I thought that the networking setup for Fedora 9 on a Hyper V virtual machine wasn’t working.
The environment is Windows 2008 Server on x64 with the RTM release of Hyper V. I then created a VM and installed Fedora 9 x64 from a DVD ISO - it took a while as I started with a multiple CPU, standard network adapter approach and it kept crashing during the install; when I changed to single CPU and “Legacy” network adapter it installed cleanly - given that Fedora isn’t a “supported” Hyper V OS I can’t really complain.
The problem I then came to was that it appeared that DNS wasn’t working, i.e. in Firefox, if I stuck in a URL, it came back with an error rather than showing the page. I then proceeded to go off on a wild goose chase checking all the Fedora networking setup and reading about Hyper V and it’s “synthetic” network adapter approach, but still couldn’t solve it. Everything seemed to be installed and configured exactly as everybody who had written about it had said…so it should be working right?
It was…but the problem is that Firefox was trying to resolve the name of the URL using IPv6 rather than IPv4…and my network was configured without an IPv6 DNS - I don’t need IPv6 and I’m perfectly happy with IPv4 so that’s what I use. I only discovered this by chance as I wondered whether it might be a Firefox issue (everything else ruled out kinda thinking), so I used the Konqueror web browser to see if it had the same issue and hey presto it was working fine whilst Firefox wasn’t.
How to fix Firefox? Well, basically as indicated in this post on the OpenSUSE website - essentially, you go to the URL “about:config” in Firefox, filter for “network.disable.IPv6″ and set it to TRUE instead of FALSE (double click it to change the value). Then it all works fine.