I had Parallels running (almost) perfectly using Ubuntu Edgy as a host. Now that I have upgraded to Feisty, networking is broken. A previous poster mentions this problem and I am having it too. After applying the changes to prl_net.c specified in this thread, I was able to compile the kernel drivers, but I have not been able to access my host from my guest instance. A SAMBA network share that used to work is no longer accessible, and I cannot connect to Apache on port 80 from the guest, although I can access it and the network share from other PCs. My guess is that the modifications to the network driver to make it compile with 2.6.19 and later kernels have some unintended consequenses. Any idea when an official update from Parallels that will compile without modification on the newer kernels will be available? Thanks!
Camerooni, I don't see why you're unable to access the host from the guest. I'm using kernel 2.6.21.1 on my debian host and I can access my host's share from the guest without a hitch. If you're still having trouble at this point, I can think of 3 possible sources to look at: 1) Iptables might not be configured to allow traffic from the guest ip address to access ports 137,138,139 on the host. 2) Samba is configured to allow other machines except for the guest to access its shares. (Restricted by IP address?) 3) Fiesty's kernel may be configured differently than Edgy or Dapper's kernels. You might have to recompile the kernel so that it closely matches Edgy's kernel. If you're not up to compiling your kernel, you might as well as downgrade the kernel to Edgy's kernel. I don't recommend downgrading the kernel unless it solves all the problems that the current kernel appears to break. Those are the obvious ones I can think of off the top of my head. Since I'm using the current stable kernel from kernel.org, this rules out the prlnet.c patch as being suspect. I'm more inclined to believe its your configuration or perhaps Feisty's kernel.
Thanks for the reply, I appreciate the information and the time you took to respond. After digging some more I've been able to get a better picture of what is going on. Using wireshark, I was able to determine that packets are flowing just fine from the guest to the host. If I start Apache on the host and request a Web page from the guest, I can see that Apache gets the request and sends back the response, but the guest never receives it -- it asks for retransmissions a few times before giving up. If I start IIS on the guest and make a request from the host, I see a few SYN packets, but no response from the guest. Oddly, I can access network shares and IIS on the guest without problems from another machine. It is only the host who is unable to communicate with the guest. I'm no stranger to recompiling a kernel but I'm not quite sure where to start here.