Xen users - Apr 2005 - Problem with network connection in domU

Hi list 

When I create a domU the network isn''t reachable when it''s
loaded. Only if I
do a xm console domUname and do some sort of network activity like pinging 
an outside host or traceroute. First then there''s network connection
from
the outside to services like webserver etc. 

What can cause this? 

I''m using Xen 2.0.5 stable domU from binary dist and recompiled dom0
myself.

-- 
Med venlig hilsen / Best regards
Lars E. D. Jensen
ledj@dcmedia.biz - http://dcmedia.biz

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Am Donnerstag, den 21.04.2005, 12:37 +0200 schrieb Lars E. D.
Jensen:
> When I create a domU the network isn''t reachable when
it''s loaded. Only if I
> do a xm console domUname and do some sort of network activity like pinging 
> an outside host or traceroute. First then there''s network
connection from
> the outside to services like webserver etc. 
That''s very few information. Sounds like an ARP/MAC problem. Maybe all
your domUs use the same MAC? On dom0, compare output of 

  arp -n
  brctl showmacs xen-br0

before and after pinging.

/nils.


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> That''s very few information. Sounds like an ARP/MAC problem. Maybe
all
> your domUs use the same MAC? On dom0, compare output of  
> 
>   arp -n
>   brctl showmacs xen-br0 
> 
> before and after pinging.
Hi Nils 

Sorry for so little information, but I''m still a bit xen newbie :) 

The weird thing is that I went to lunch and when I came back the problem was 
gone!? The network connection is functional now without needing to ping etc. 
from inside the xen virtual server 

Still I get this output from dom0: 

xen010405:~# arp -n
Address                  HWtype  HWaddress           Flags Mask            
Iface
217.195.178.225          ether   00:0D:88:79:25:14   C                     
xen-br0 

xen010405:~# brctl showmacs xen-br0
port no mac addr                is local?       ageing timer
 1     00:0c:f1:99:e2:08       no               275.61
 1     00:0d:88:79:25:14       no                 0.00
 1     00:12:a9:0a:3a:c0       no                 1.66
 1     00:12:a9:0a:3a:d7       no                 1.91
 1     00:30:48:2d:28:6c       yes                0.00
 2     aa:00:00:15:71:50       no                37.76
 2     fe:ff:ff:ff:ff:ff       yes                0.00 


-- 
Med venlig hilsen / Best regards
Lars E. D. Jensen
ledj@dcmedia.biz - http://dcmedia.biz 


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Am Donnerstag, den 21.04.2005, 13:53 +0200 schrieb Lars E. D.
Jensen:
> > That''s very few information. Sounds like an ARP/MAC problem.
Maybe all
> > your domUs use the same MAC? On dom0, compare output of  
> > 
> >   arp -n
> >   brctl showmacs xen-br0 
> > 
> > before and after pinging.
> 
> Hi Nils 
> 
> Sorry for so little information, but I''m still a bit xen newbie :)
> 
> The weird thing is that I went to lunch and when I came back the problem
was
> gone!? 
I hate problems disappearing without cause more than problems not
disappearing ;-)

> The network connection is functional now without needing to ping etc. 
> from inside the xen virtual server 
And if you shutdown the domUs and recreate them?

> Still I get this output from dom0: 
[...]

Interesting is not the output, but the _difference_ between two of them.
As you obviously bridge, this would be the procedure:

  # domU is not reachable
  brctl showmacs xen-br0

  # make domU reachable by tricky pings
  brctl showmacs xen-br0

Does something change?

/nils.


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> > The weird thing is that I went to lunch and when I came back the
problem
> > was gone!?
>
> I hate problems disappearing without cause more than problems not
> disappearing ;-)
Yeah me too!
>
> > The network connection is functional now without needing to ping etc.
> > from inside the xen virtual server
>
> And if you shutdown the domUs and recreate them?
Yes, I shutdown and created lots of times. So it''s a bit strange.
>
> > Still I get this output from dom0:
>
> [...]
>
> Interesting is not the output, but the _difference_ between two of them.
> As you obviously bridge, this would be the procedure:
>
>   # domU is not reachable
>   brctl showmacs xen-br0
>
>   # make domU reachable by tricky pings
>   brctl showmacs xen-br0
>
> Does something change?
Yes, but now I can''t check it since it''s working again.
But now I know where to post and what to post if the problem arises again.

Thanks for your patience :)

-- 
Med venlig hilsen / Best regards
Lars E. D. Jensen - DCmedia
ledj@dcmedia.biz - http://dcmedia.biz

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