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  1. #1

    Qemu networking; unable to create a working bridge?


    Hello!

    I have a fairly fresh install of gentoo in which I decided to convert my vmware workstation 10 guest to run under qemu instead. That was easy and very straight forward however when it comeds to the networking part with which I always tend to go for bridging whatever the virtualization software but in qemu I have not been able to connect anywhere through ethernet as of yet.

    I have followed a bunch of howto's so far and with some settings I am able to get a IP from my router (192.168.1.0/24) but I am unable to reach anywhere still, how is that possible??!

    Most recent guide was this: (swedish!) it.bmc.uu.se/andlov/docs/linux/kvm/host/network.php

    This is my machine start-up script as it looks at the moment with pretty much default network settings but as you see I have tested the marked out options in all (for me) possible ways..

    Code:
    #!/bin/bash 
    exec qemu-system-x86_64 \
    -enable-kvm \
    -cpu host \
    -drive file=/mnt/sda6/virtual/Ubuntu_Server_Webnode.img,if=virtio \
    -net nic \
    -net user \
    -m 2G \
    -vga std -nographic -vnc :10 \
    -name "Ubuntu Webnode" \
    $@
     
    #-net tap,ifname=tap0,script=no,downscript=no \
    #-net nic \
    #-net bridge,br=br0 \
    #-device e1000,netdev=net0,mac=DE:AD:BE:EF:AA:D2 \
    #-netdev tap,id=net0 \
    #-net nic,vlan=0 \
    #-net user,vlan=0 \
    #-net tap,ifname=br0,script=no,downscript=no \
    #-netdev user,id=net0,net=192.168.2.0/24 \
    #-vga std -nographic -vnc :10,tls,x509,sasl \
    #-net nic,vlan=1 hostname=Ubuntu_webnode \

  2. #2
    Linux Guru Rubberman's Avatar
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    This is probably a routing (DNS) issue. Post the contents of /etc/resolv.conf here.
    Sometimes, real fast is almost as good as real time.
    Just remember, Semper Gumbi - always be flexible!

  3. #3
    Quote Originally Posted by Rubberman View Post
    This is probably a routing (DNS) issue. Post the contents of /etc/resolv.conf here.
    I havent even tried connecting to any domains, so I doubt it has to do with any dns. I normally try my connections with ssh to and from local ip's and I am unable to connect either way.
    The guest receives for example 192.168.1.106 from my router and still I am unable to wget 192.168.1.200 (which is my router/gw)

    This is what I expect: (screenshot from host)
    uploads.tapatalk-cdn.com/20170102/1ecffc41ca21aa783f5b97265a8beccb.jpg

    This is what I get: (screenshot from guest)
    uploads.tapatalk-cdn.com/20170102/9234503124af791b8a9165c188ee7814.jpg

    I was not allowed to post the exact URL, so this is why my post looks like this.

    Also, to make the guest receive dhcp from gw I adjusted the networking settings in the guest script-file to:
    -net tap,ifname=tap0,script=no,downscript=no
    -net nic
    Last edited by johanlindgren; 01-02-2017 at 04:54 PM.

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  5. #4
    Ghaa oh, now I feel so stupid

    The problem was a small iptables script from when I ran the machine in vmware, I didnt even know I had it there, but after running:

    Code:
    ipt="/sbin/iptables"
    $ipt -P INPUT ACCEPT
    $ipt -P FORWARD ACCEPT
    $ipt -P OUTPUT ACCEPT
    $ipt -F
    $ipt -X
    $ipt -t nat -F
    $ipt -t nat -X
    $ipt -t mangle -F
    $ipt -t mangle -X
    $ipt iptables -t raw -F 
    $ipt -t raw -X
    it worked

  6. #5
    Linux Guru Rubberman's Avatar
    Join Date
    Apr 2009
    Location
    I can be found either 40 miles west of Chicago, in Chicago, or in a galaxy far, far away.
    Posts
    13,930
    Yeah. Been there. Done that. Felt stupid as well!
    Sometimes, real fast is almost as good as real time.
    Just remember, Semper Gumbi - always be flexible!

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