Hi Laine,
Aside from the problem Daniel pointed out in his reply, this is probably the *least* desirable way to get this functionality, and should only be used if you are unable to use any other network connection type.
I tried what Daniel told me. But seems there are some problems. At first, I just want get QEMU (inside the KVM) VNC output, so I redirect 590# port. But nothing happened. Then I think, "let me try ssh redirect as I want to ssh into the virtual machine". Here is my qemu option: <qemu:commandline> <qemu:arg value='-net'/> <qemu:arg value='user,hostfwd=tcp:127.0.0.1:2222-:22'/> </qemu:commandline> But it doesn't work neither. No responding from "ssh user@127.0.0.1 -p 2222". I don't know what's wrong here.
What I am missing here? I also found there was a patch for user mode port forwarding [2]. Does that mean I can write libvirt xml directly to do port forwarding?
No, that patch "died in committee"; in general it's a good idea, but it needs to be done in a way that is useful for all types of interface, not just usermode. Unfortunately nobody has had the combination of enough time + enough motivation to carry it through.
Shame, that's a good idea indeed.
If so, could someone give me hint on how to write one? The last question is, do I have to change the interface type from "network" to "user" so that I can do port forwarding?
No, you don't. Please take a look here:
http://wiki.libvirt.org/page/Networking#Forwarding_Incoming_Connections
Alternately (and a simpler solution), you could use a bridged or direct (macvtap) network connection for your guest, and then the guest would have an IP address directly on the physical network and no need to have any ports forwarded.
I'll try what you suggest, and see if it works. Thanks! :) Regards, chenwj -- Wei-Ren Chen (陳韋任) Computer Systems Lab, Institute of Information Science, Academia Sinica, Taiwan (R.O.C.) Tel:886-2-2788-3799 #1667 Homepage: http://people.cs.nctu.edu.tw/~chenwj