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Hi everyone. I'm running CentOS 5.7 with xen installed via the Virtualization yum group. I installed an Ubuntu 11.04 domU with virt-manager and have configured the network bridge according to ...
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  1. #1
    Just Joined!
    Join Date
    Sep 2011
    Posts
    1

    xen network bridge problem


    Hi everyone.

    I'm running CentOS 5.7 with xen installed via the Virtualization yum group.

    I installed an Ubuntu 11.04 domU with virt-manager and have configured the network bridge according to the guide here:
    wiki.kartbuilding.net/index.php/Xen_Networking]Xen Networking - Wiki

    I also changed the mac address according to the recommendation here:
    adminstuff.wikidot.com/xen-bridge-networking]Xen Bridge Networking - Adminstuff

    I am able to ping the IP of the domU from dom0 and vice versa, but I cannot access the internet from the domU. Any suggestions?

    my iptables don't show forwarding to vif1.0 the the domU's IP address.
    Code:
    # iptables -L
    Chain INPUT (policy ACCEPT)
    target     prot opt source               destination         
    ACCEPT     udp  --  anywhere             anywhere            udp dpt:domain 
    ACCEPT     tcp  --  anywhere             anywhere            tcp dpt:domain 
    ACCEPT     udp  --  anywhere             anywhere            udp dpt:bootps 
    ACCEPT     tcp  --  anywhere             anywhere            tcp dpt:bootps 
    
    Chain FORWARD (policy ACCEPT)
    target     prot opt source               destination         
    ACCEPT     all  --  anywhere             192.168.122.0/24    state RELATED,ESTABLISHED 
    ACCEPT     all  --  192.168.122.0/24     anywhere            
    ACCEPT     all  --  anywhere             anywhere            
    REJECT     all  --  anywhere             anywhere            reject-with icmp-port-unreachable 
    REJECT     all  --  anywhere             anywhere            reject-with icmp-port-unreachable 
    ACCEPT     all  --  max                  anywhere            PHYSDEV match --physdev-in vif1.0 
    ACCEPT     udp  --  anywhere             anywhere            PHYSDEV match --physdev-in vif1.0 udp spt:bootpc dpt:bootps 
    
    Chain OUTPUT (policy ACCEPT)
    target     prot opt source               destination

    Here's the config for my VM:
    Code:
    # cat /etc/xen/rm 
    name = "rm"
    maxmem = 512
    memory = 404
    vcpus = 2
    builder = "hvm"
    kernel = "/usr/lib/xen/boot/hvmloader"
    boot = "c"
    pae = 1
    acpi = 1
    apic = 1
    localtime = 0
    on_poweroff = "destroy"
    on_reboot = "restart"
    on_crash = "restart"
    device_model = "/usr/lib64/xen/bin/qemu-dm"
    sdl = 0
    vnc = 1
    vncunused = 1
    keymap = "en-us"
    disk = [ "file:/var/lib/xen/images/rm.img,hda,w", ",hdc:cdrom,r" ]
    vif = [ "mac=02:00:00:00:00:01,ip=___.__.___.16" ]
    parallel = "none"
    serial = "pty"

    Any help is much appreciated!

  2. #2
    Just Joined!
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    Dec 2007
    Location
    Bangalore
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    You will need to check the vif configuration. I have a VM and its config reads as:

    vif = [ 'mac=___MAC___, bridge=xenbr0', 'bridge=virbr0', ]

    This link could help you:
    Guest Configuration

  3. #3
    Just Joined!
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    May 2012
    Location
    Caracas
    Posts
    1
    I crossed my path to the same problem,

    I installed Xen3.0 and several Debian Etch on DomU's that worked just fine,
    Then I Installed an Ubuntu Natty (11.04) as another DomU, and I got no internet at all...
    the problem was the MTU:

    etch:~# ifconfig
    Code:
    eth0      Link encap:Ethernet  HWaddr 00:16:3E:74:CB:77  
              inet addr:192.168.11.101  Bcast:255.255.255.255  Mask:255.255.255.0
              UP BROADCAST RUNNING MULTICAST  MTU:576  Metric:1
              RX packets:1809 errors:0 dropped:0 overruns:0 frame:0
              TX packets:172 errors:0 dropped:0 overruns:0 carrier:0
              collisions:0 txqueuelen:1000 
              RX bytes:478086 (466.8 KiB)  TX bytes:23465 (22.9 KiB)
              Interrupt:26 
    
    lo        Link encap:Local Loopback  
              inet addr:127.0.0.1  Mask:255.0.0.0
              inet6 addr: ::1/128 Scope:Host
              UP LOOPBACK RUNNING  MTU:16436  Metric:1
              RX packets:0 errors:0 dropped:0 overruns:0 frame:0
              TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
              collisions:0 txqueuelen:0 
              RX bytes:0 (0.0 b)  TX bytes:0 (0.0 b)
    natty:~# ifconfig
    Code:
    eth0      Link encap:Ethernet  HWaddr 00:16:3E:74:CA:21  
              inet addr:192.168.11.102  Bcast:255.255.255.255  Mask:255.255.255.0
              UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
              RX packets:1809 errors:0 dropped:0 overruns:0 frame:0
              TX packets:172 errors:0 dropped:0 overruns:0 carrier:0
              collisions:0 txqueuelen:1000 
              RX bytes:478086 (466.8 KiB)  TX bytes:23465 (22.9 KiB)
              Interrupt:26 
    
    lo        Link encap:Local Loopback  
              inet addr:127.0.0.1  Mask:255.0.0.0
              inet6 addr: ::1/128 Scope:Host
              UP LOOPBACK RUNNING  MTU:16436  Metric:1
              RX packets:0 errors:0 dropped:0 overruns:0 frame:0
              TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
              collisions:0 txqueuelen:0 
              RX bytes:0 (0.0 b)  TX bytes:0 (0.0 b)
    So I changed the mtu of the Natty girl:

    natty:~# ifconfig eth0 mtu 576

    and everything is working fine now

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