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Thread: IPv6 unavaliable after idle

  1. #1
    Join Date
    Aug 2011
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    IPv6 unavaliable after idle

    I have several Ubuntu 12.04.2 64bit server VMs running under XenServer 6.1.

    Whenever they are left for ~30 mins with no traffic over ipv6, the network becomes unavailable, requiring the restart of the networking service to bring it back up. IPv4 is still active.

    Code:
    :~# ping6 google.com
    connect: Network is unreachable
    They are able to ping other VMs running on the same Host OS, but nothing above the host, even though the host and other VMs have IPv6 access.

    Any help is appreciated. Wader
    Last edited by iWader; March 25th, 2013 at 12:18 AM.

  2. #2
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    Re: IPv6 unavaliable after idle

    What kind of IPv6 are you using?

    What is the output of:

    Code:
    mtr -nrc2 ipv6.google.com
    dmesg | grep -i ipv6
    ip -6 addr show

  3. #3
    Join Date
    Aug 2011
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    4

    Re: IPv6 unavaliable after idle

    Its native IPv6 provided by OVH

    mtr -nrc2 ipv6.google.com

    Code:
    :~# mtr -nrc2 ipv6.google.com
    HOST: lithium.iwader.co.uk        Loss%   Snt   Last   Avg  Best  Wrst StDev
    dmesg | grep -i ipv6

    Code:
    :~# dmesg | grep -i ipv6
    [    2.693689] IPv6: ADDRCONF(NETDEV_UP): eth0: link is not ready
    [    2.693694] IPv6: ADDRCONF(NETDEV_UP): eth1: link is not ready
    ip -6 addr show

    Code:
    :~# ip -6 addr show
    1: lo: <LOOPBACK,UP,LOWER_UP> mtu 16436
        inet6 ::1/128 scope host
           valid_lft forever preferred_lft forever
    2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qlen 1000
        inet6 2607:5300:60:2f30::2/64 scope global
           valid_lft forever preferred_lft forever
        inet6 fe80::ff:fe5b:19b/64 scope link
           valid_lft forever preferred_lft forever
    Last edited by iWader; March 25th, 2013 at 04:41 PM.

  4. #4
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    Re: IPv6 unavaliable after idle

    What kind of network is between the host and the guest OS? NAT? Bridged? ... ?

    Maybe the first next hop (host OS or router) forgets the route to guest OS. Or maybe the guest OS does not answer ICMP6-who-has requests?

  5. #5
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    Aug 2011
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    Re: IPv6 unavaliable after idle

    Quote Originally Posted by sanderj View Post
    What kind of network is between the host and the guest OS? NAT? Bridged? ... ?

    Maybe the first next hop (host OS or router) forgets the route to guest OS. Or maybe the guest OS does not answer ICMP6-who-has requests?
    Its running under routed networking. My host (OVH) doesn't allow bridged adapters.

    The kernel provided by OVH for the host os (XenServer 6.1) its pre-configured for both ipv4 and ipv6 routed networking, so i dont think the issues lies there.

  6. #6
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    Re: IPv6 unavaliable after idle

    Routed? So the Host is taking care of *routing*?

    Oh, wait: is the XenServer provided by OVH? If so, ask them what is going on.

  7. #7
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    Re: IPv6 unavaliable after idle

    PS:

    What does

    Code:
    rdisc6 eth0
    tell you?

  8. #8
    Join Date
    Aug 2011
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    4

    Re: IPv6 unavaliable after idle

    Quote Originally Posted by sanderj View Post
    Routed? So the Host is taking care of *routing*?

    Oh, wait: is the XenServer provided by OVH? If so, ask them what is going on.
    Yes, all traffic from the VMs must be routed through the host os rather than directly connecting to their network. I already have a post on their forums, not very active though, doubt i would get help via. ticket

    Quote Originally Posted by sanderj View Post
    PS:

    What does

    Code:
    rdisc6 eth0
    tell you?
    Code:
    :~# rdisc6 eth0
    Soliciting ff02::2 (ff02::2) on eth0...
    
    
    Hop limit                 :           64 (      0x40)
    Stateful address conf.    :           No
    Stateful other conf.      :           No
    Router preference         :       medium
    Router lifetime           :         1800 (0x00000708) seconds
    Reachable time            :  unspecified (0x00000000)
    Retransmit time           :  unspecified (0x00000000)
     Source link-layer address: 6C:9C:ED:BA:EC:40
     MTU                      :         1500 bytes (valid)
     Prefix                   : 2607:5300:60:2f00::/56
      Valid time              :      2592000 (0x00278d00) seconds
      Pref. time              :       604800 (0x00093a80) seconds
     from fe80::6e9c:edff:feba:ec40
    
    
    Hop limit                 :           64 (      0x40)
    Stateful address conf.    :           No
    Stateful other conf.      :           No
    Router preference         :       medium
    Router lifetime           :         1800 (0x00000708) seconds
    Reachable time            :  unspecified (0x00000000)
    Retransmit time           :  unspecified (0x00000000)
     Source link-layer address: 6C:9C:ED:BA:EB:40
     MTU                      :         1500 bytes (valid)
     Prefix                   : 2607:5300:60:2f00::/56
      Valid time              :      2592000 (0x00278d00) seconds
      Pref. time              :       604800 (0x00093a80) seconds
     from fe80::6e9c:edff:feba:eb40

  9. #9
    Join Date
    Nov 2006
    Location
    Wisconsin, USA
    Beans
    920
    Distro
    Ubuntu 13.04 Raring Ringtail

    Re: IPv6 unavaliable after idle

    So, are there supposed to be two upstream routers?

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