master@bradleyland.com
2005-Sep-18 19:37 UTC
[Xen-users] Unexpected (?) bridging behavior in 2.0.7/FC4
I''ve got 2.0.7 running on a machine with 1 physical interface and two
bridges, like so --
bridge name bridge id STP enabled interfaces
xen-br0 8000.0040f4ce392f no eth1
vif5.0
vif9.0
xenbr1 8000.feffffffffff no vif5.1
vif9.1
Bridge xenbr1 does not have an IP assigned, as I want vif5.1, vif9.1 to be
on an "untethered" bridge so it is isolated from dom0 --
[root@teegeeack ~]# ifconfig xenbr1
xenbr1 Link encap:Ethernet HWaddr FE:FF:FF:FF:FF:FF
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:47 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:1860 (1.8 KiB) TX bytes:0 (0.0 b)
If I run tcpdump -i xenbr1 on dom0, should I see all traffic on xenbr1
(vif5.1 and vif9.1)? In this case the domU on vif5.1 has IP 192.168.5.8
and vif9.1 has IP 192.168.5.9. If I run tcpdump on xenbr1 and ping .8, I
don''t see any packets. If I run tcpdump on xenbr1 and ping .9, I do see
the packets.
So, I suppose the question is -- is this expected? What I want is for the
bridge to act like a hub, not a switch, but my testing shows it''s not
acting like either. My intent is to use snort on a bridge without an IP
assigned.
I''ve tried running tcpdump on the vifs in dom0 as well. Only the pings
to
192.168.5.9 are captured. Am I missing something?
Signed,
Confused
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Marcus Brown
2005-Sep-19 00:21 UTC
Re: [Xen-users] Unexpected (?) bridging behavior in 2.0.7/FC4
Hi, master@bradleyland.com wrote:> I''ve got 2.0.7 running on a machine with 1 physical interface and two > bridges, like so -- > > bridge name bridge id STP enabled interfaces > xen-br0 8000.0040f4ce392f no eth1 > vif5.0 > vif9.0 > xenbr1 8000.feffffffffff no vif5.1 > vif9.1 > > Bridge xenbr1 does not have an IP assigned, as I want vif5.1, vif9.1 to be > on an "untethered" bridge so it is isolated from dom0 -- > > [root@teegeeack ~]# ifconfig xenbr1 > xenbr1 Link encap:Ethernet HWaddr FE:FF:FF:FF:FF:FF > UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 > RX packets:47 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:1860 (1.8 KiB) TX bytes:0 (0.0 b) > > If I run tcpdump -i xenbr1 on dom0, should I see all traffic on xenbr1 > (vif5.1 and vif9.1)? In this case the domU on vif5.1 has IP 192.168.5.8 > and vif9.1 has IP 192.168.5.9. If I run tcpdump on xenbr1 and ping .8, I > don''t see any packets. If I run tcpdump on xenbr1 and ping .9, I do see > the packets.tcpdump should show all traffic whether the bridge has an IP or not. Can you tcpdump each vif and get a result that way? Can you tcpdump from inside the domU and get a result? I assume your network works correctly? Perhaps check for overlapping subnets?> > So, I suppose the question is -- is this expected? What I want is for the > bridge to act like a hub, not a switch, but my testing shows it''s not > acting like either.I don''t understand your meaning.> My intent is to use snort on a bridge without an IP assigned.I think that should work.> I''ve tried running tcpdump on the vifs in dom0 as well. Only the pings to > 192.168.5.9 are captured. Am I missing something?Make sure the vif''s in dom0 don''t have an IP assigned. tcpdumping on each vif will show traffic to/from the domU it''s attached to. Marcus. _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
master@bradleyland.com
2005-Sep-19 02:00 UTC
Re: [Xen-users] Unexpected (?) bridging behavior in 2.0.7/FC4
> Hi, > > master@bradleyland.com wrote: >> I''ve got 2.0.7 running on a machine with 1 physical interface and two >> bridges, like so -- >> >> bridge name bridge id STP enabled interfaces >> xen-br0 8000.0040f4ce392f no eth1 >> vif5.0 >> vif9.0 >> xenbr1 8000.feffffffffff no vif5.1 >> vif9.1 >> >> Bridge xenbr1 does not have an IP assigned, as I want vif5.1, vif9.1 to >> be >> on an "untethered" bridge so it is isolated from dom0 -- >> >> [root@teegeeack ~]# ifconfig xenbr1 >> xenbr1 Link encap:Ethernet HWaddr FE:FF:FF:FF:FF:FF >> UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 >> RX packets:47 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:1860 (1.8 KiB) TX bytes:0 (0.0 b) >> >> If I run tcpdump -i xenbr1 on dom0, should I see all traffic on xenbr1 >> (vif5.1 and vif9.1)? In this case the domU on vif5.1 has IP 192.168.5.8 >> and vif9.1 has IP 192.168.5.9. If I run tcpdump on xenbr1 and ping .8, I >> don''t see any packets. If I run tcpdump on xenbr1 and ping .9, I do see >> the packets. > > tcpdump should show all traffic whether the bridge has an IP or not. > Can you tcpdump each vif and get a result that way? > Can you tcpdump from inside the domU and get a result? > I assume your network works correctly? > Perhaps check for overlapping subnets? > >> >> So, I suppose the question is -- is this expected? What I want is for >> the >> bridge to act like a hub, not a switch, but my testing shows it''s not >> acting like either. > > I don''t understand your meaning. > >> My intent is to use snort on a bridge without an IP assigned. > > I think that should work. > >> I''ve tried running tcpdump on the vifs in dom0 as well. Only the pings >> to >> 192.168.5.9 are captured. Am I missing something? > > Make sure the vif''s in dom0 don''t have an IP assigned. > > tcpdumping on each vif will show traffic to/from the domU it''s attached > to. > > > Marcus. >Thanks for the response Marcus. I figured it out -- my mistake. I was pinging 192.168.5.8 and 192.168.5.9 from dom0 (IP 192.168.2.5 -- different network) which is routed to one of the domU machines. When I tcpdmp -i xenbr1 on dom0 and the traffic is between .8 and .9, I see both machine''s traffic as I would expect. I think it''s working as it should, but I''ve got more experimenting to do. _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
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