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Wolfgang Formann

2009-Jun-09 08:27 UTC

[Xen-users] Cannot ping DomU from Dom0 / cannot ping same site from two DomUs at the same time

Hello!

I have two problems. One is, that I cannot ping a DomU from Dom0 (or any
other host in my local network) and the second one is, that I cannot
ping the same site (eg. www.suse.com) from two DomU''s at the same time.

I have a fresh installation of openSuse 11.0 with Kernel
2.6.25.20-0.1-xen and my box has two physical ethernet cards.

As far as I have investigated, eth0 is the one which is grabbed by the
Xen-scripts, als you can see here:

# brctl show
bridge name     bridge id               STP enabled     interfaces
eth0            8000.003048d69cfa       no              peth0
                                                        tap0
                                                        vif7.0

The file xend-config.sxp is unmodified, I filter here all those comments:
# egrep -v "^$|^#" xend-config.sxp
(xen-api-server ((unix none)))
(xend-unix-server yes)
(xend-relocation-hosts-allow ''^localhost$
^localhost\\.localdomain$'')
(network-script network-bridge)
(vif-script vif-bridge)
(dom0-min-mem 512)
(dom0-cpus 0)
(vncpasswd '''')

ifconfig shows these one, while one DomU is running.

# ifconfig -a
eth0      Link encap:Ethernet  HWaddr 00:30:48:D6:9C:FA
          inet addr:192.168.222.16  Bcast:192.168.222.255 Mask:255.255.255.0
          inet6 addr: fe80::230:48ff:fed6:9cfa/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:1032642 errors:0 dropped:0 overruns:0 frame:0
          TX packets:668426 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:1101565708 (1050.5 Mb)  TX bytes:83483260 (79.6 Mb)

eth1      Link encap:Ethernet  HWaddr 00:30:48:D6:9C:FB
          inet addr:192.168.224.1  Bcast:192.168.224.255  Mask:255.255.255.0
          inet6 addr: fe80::230:48ff:fed6:9cfb/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:2093348 errors:0 dropped:0 overruns:0 frame:0
          TX packets:2372864 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:177871101 (169.6 Mb)  TX bytes:7055283604 (6728.4 Mb)
          Interrupt:20 Base address:0xe000

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:329651 errors:0 dropped:0 overruns:0 frame:0
          TX packets:329651 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:1269637544 (1210.8 Mb)  TX bytes:1269637544 (1210.8 Mb)

peth0     Link encap:Ethernet  HWaddr 00:30:48:D6:9C:FA
          inet6 addr: fe80::230:48ff:fed6:9cfa/64 Scope:Link
          UP BROADCAST RUNNING PROMISC MULTICAST  MTU:1500  Metric:1
          RX packets:1322260 errors:0 dropped:0 overruns:0 frame:0
          TX packets:739433 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:1319675729 (1258.5 Mb)  TX bytes:92076405 (87.8 Mb)
          Interrupt:20 Base address:0xa000

tap0      Link encap:Ethernet  HWaddr 00:FF:C5:E9:26:66
          inet6 addr: fe80::2ff:c5ff:fee9:2666/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:216 errors:0 dropped:0 overruns:0 frame:0
          TX packets:1313 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:500
          RX bytes:40640 (39.6 Kb)  TX bytes:96970 (94.6 Kb)

vif7.0    Link encap:Ethernet  HWaddr FE:FF:FF:FF:FF:FF
          inet6 addr: fe80::fcff:ffff:feff:ffff/64 Scope:Link
          UP BROADCAST RUNNING PROMISC MULTICAST  MTU:1500  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:1497 overruns:0 carrier:0
          collisions:0 txqueuelen:32
          RX bytes:0 (0.0 b)  TX bytes:0 (0.0 b)

It also seems, that all those various arp-addresses are set up fine.
00:16:3e:1f:0b:3c is the one I see inside the DomU

# brctl showmacs eth0
port no mac addr                is local?       ageing timer
  1     00:03:c5:01:4d:52       no                 0.29
  2     00:16:3e:1f:0b:3c       no               109.27
  1     00:17:f2:c4:a0:ca       no                 8.32
  1     00:30:48:d6:9c:fa       yes                0.00
  1     00:50:ba:70:05:87       no               193.89
  1     00:e0:7d:79:a6:c1       no                 0.92
  2     00:ff:c5:e9:26:66       yes                0.00
  1     08:00:20:0b:cf:35       no                 0.92
  3     fe:ff:ff:ff:ff:ff       yes                0.00

Now when I do a ping from Dom0 to DomU I see the following tcpdump:
09:45:43.191701 arp who-has 192.168.222.102 tell 192.168.222.16
and no answer within a few seconds.

So it seems that something with arp is not fine. Any ideas what to do next?

#######

The other problem which may be related is a little bit more strange. I have set
up two DomU''s, one with Vista-32bit and one with Vista-64bit. Both have
differend IP-addresses and different MAC-addresses. I can ping whatever host (in
my LAN or in the internet) with both DomU''s. No problem. I can also
ping any
host, even on a different subnet in my LAN from both DomU''s at the same
time.

But when I try to ping www.suse.com (or any other host in the internet) at the
same time only that DomU pings successfully where I started the ping first, the
other DomU fails. If one DomU pings www.slashdot.org an other other pings
www.suse.com both pings work fine. Ping also works fine, when I ping any other
host in my LAN from both DomU''s. This one puzzles mee too. I
crosschecked and
can ping from any other pair of my machines to the outside without problems.

Thanks
Wolfgang


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Fajar A. Nugraha

2009-Jun-09 09:04 UTC

head link

Re: [Xen-users] Cannot ping DomU from Dom0 / cannot ping same site from two DomUs at the same time

On Tue, Jun 9, 2009 at 3:27 PM, Wolfgang Formann<wformann@arcor.de>
wrote:> Now when I do a ping from Dom0 to DomU I see the following tcpdump:
> 09:45:43.191701 arp who-has 192.168.222.102 tell 192.168.222.16
> and no answer within a few seconds.
>
> So it seems that something with arp is not fine. Any ideas what to do next?
Dump Suse?

Kidding :)
If it were ARP issue your domU would be completely disconnected from
network. Since you say you can ping other host from domU, that''s
probably not it. I''d check domU''s firewall first, most likely
its
blocking things (including ICMP echo). Disable it first for
troubleshooting purposes.
> The other problem which may be related is a little bit more strange. I have
set
> up two DomU''s, one with Vista-32bit and one with Vista-64bit. Both
have
> differend IP-addresses and different MAC-addresses. I can ping whatever
host (in
> my LAN or in the internet) with both DomU''s. No problem. I can
also ping any
> host, even on a different subnet in my LAN from both DomU''s at the
same time.
>
> But when I try to ping www.suse.com (or any other host in the internet) at
the
> same time only that DomU pings successfully where I started the ping first,
the
> other DomU fails. If one DomU pings www.slashdot.org an other other pings
> www.suse.com both pings work fine. Ping also works fine, when I ping any
other
> host in my LAN from both DomU''s. This one puzzles mee too. I
crosschecked and
> can ping from any other pair of my machines to the outside without
problems.

At this point I suggest check your networking setup. Perhaps your
router/firewall to the internet is doing something funny?

-- 
Fajar

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Wolfgang Formann

2009-Jun-09 10:07 UTC

head link

Re: [Xen-users] Cannot ping DomU from Dom0 / cannot ping same site from two DomUs at the same time

Fajar A. Nugraha wrote:> On Tue, Jun 9, 2009 at 3:27 PM, Wolfgang Formann<wformann@arcor.de>
wrote:
> 
>>Now when I do a ping from Dom0 to DomU I see the following tcpdump:
>>09:45:43.191701 arp who-has 192.168.222.102 tell 192.168.222.16
>>and no answer within a few seconds.
>>
>>So it seems that something with arp is not fine. Any ideas what to do
next?
> 
> 
> Dump Suse?
> 
> Kidding :)
:-)
> If it were ARP issue your domU would be completely disconnected from
> network. Since you say you can ping other host from domU, that''s
> probably not it. I''d check domU''s firewall first, most
likely its
> blocking things (including ICMP echo). Disable it first for
> troubleshooting purposes.
Argh! I forgot that "fine" Windows firewall.

Ping from one DomU to the other works now fine.
Ping from any host in my LAN to DomU works fine too.

Shame on me, many thanks to you.
>>The other problem which may be related is a little bit more strange. I
have set
>>up two DomU''s, one with Vista-32bit and one with Vista-64bit.
Both have
>>differend IP-addresses and different MAC-addresses. I can ping whatever
host (in
>>my LAN or in the internet) with both DomU''s. No problem. I can
also ping any
>>host, even on a different subnet in my LAN from both DomU''s at
the same time.
>>
>>But when I try to ping www.suse.com (or any other host in the internet)
at the
>>same time only that DomU pings successfully where I started the ping
first, the
>>other DomU fails. If one DomU pings www.slashdot.org an other other
pings
>>www.suse.com both pings work fine. Ping also works fine, when I ping any
other
>>host in my LAN from both DomU''s. This one puzzles mee too. I
crosschecked and
>>can ping from any other pair of my machines to the outside without
problems.
> 
> 
> 
> At this point I suggest check your networking setup. Perhaps your
> router/firewall to the internet is doing something funny?
My Router/Firewall is a good old Sun IPX (yeah! Still alive an running
NetBSD), a tcpdump on this machine shows the following:

# /usr/sbin/tcpdump -n net 192.168.222.100/30
tcpdump: listening on le0
11:46:58.189533 192.168.222.103.62525 > 192.168.222.7.53:  12258+ A?
www.suse.com. (30)
11:46:58.248031 192.168.222.7.53 > 192.168.222.103.62525:  12258* 1/3/3
A[|domain]
11:46:58.288924 192.168.222.103 > 195.135.220.3: icmp: echo request seq 128
11:46:58.311730 195.135.220.3 > 192.168.222.103: icmp: echo reply seq 128
11:46:59.276963 192.168.222.103 > 195.135.220.3: icmp: echo request seq 129
11:46:59.302697 195.135.220.3 > 192.168.222.103: icmp: echo reply seq 129
11:47:00.293260 192.168.222.103 > 195.135.220.3: icmp: echo request seq 130
11:47:00.316296 195.135.220.3 > 192.168.222.103: icmp: echo reply seq 130
11:47:01.308183 192.168.222.103 > 195.135.220.3: icmp: echo request seq 131
11:47:01.330296 195.135.220.3 > 192.168.222.103: icmp: echo reply seq 131
11:47:01.632880 arp who-has 192.168.222.7 tell 192.168.222.102
11:47:01.633120 arp reply 192.168.222.7 is-at 8:0:20:b:cf:35
11:47:01.633755 192.168.222.102.51889 > 192.168.222.7.53:  46997+ A?
www.suse.com. (30)
11:47:01.637738 192.168.222.7.53 > 192.168.222.102.51889:  46997 1/3/3 A
195.135.220.3 (171)

## here the second DomU send out a ping
11:47:01.706935 192.168.222.102 > 195.135.220.3: icmp: echo request seq 13
11:47:02.323624 192.168.222.103 > 195.135.220.3: icmp: echo request seq 132
11:47:02.347712 195.135.220.3 > 192.168.222.103: icmp: echo reply seq 132
11:47:02.761024 arp who-has 192.168.222.7 (8:0:20:b:cf:35) tell 192.168.222.103
11:47:02.761270 arp reply 192.168.222.7 is-at 8:0:20:b:cf:35
11:47:03.339145 192.168.222.103 > 195.135.220.3: icmp: echo request seq 133
11:47:03.361077 195.135.220.3 > 192.168.222.103: icmp: echo reply seq 133
11:47:04.338974 192.168.222.103 > 195.135.220.3: icmp: echo request seq 134
11:47:04.360643 195.135.220.3 > 192.168.222.103: icmp: echo reply seq 134
11:47:05.339085 192.168.222.103 > 195.135.220.3: icmp: echo request seq 135
11:47:05.361956 195.135.220.3 > 192.168.222.103: icmp: echo reply seq 135
11:47:06.354563 192.168.222.103 > 195.135.220.3: icmp: echo request seq 136
11:47:06.378167 195.135.220.3 > 192.168.222.103: icmp: echo reply seq 136

## here the second DomU send out the next ping
11:47:06.508449 192.168.222.102 > 195.135.220.3: icmp: echo request seq 14
11:47:07.382269 192.168.222.103 > 195.135.220.3: icmp: echo request seq 137
11:47:07.404318 195.135.220.3 > 192.168.222.103: icmp: echo reply seq 137
11:47:08.416702 192.168.222.103 > 195.135.220.3: icmp: echo request seq 138
11:47:08.438996 195.135.220.3 > 192.168.222.103: icmp: echo reply seq 138
11:47:09.416554 192.168.222.103 > 195.135.220.3: icmp: echo request seq 139
11:47:09.439017 195.135.220.3 > 192.168.222.103: icmp: echo reply seq 139
11:47:10.432055 192.168.222.103 > 195.135.220.3: icmp: echo request seq 140
11:47:10.454572 195.135.220.3 > 192.168.222.103: icmp: echo reply seq 140
11:47:11.447678 192.168.222.103 > 195.135.220.3: icmp: echo request seq 141
11:47:11.470148 195.135.220.3 > 192.168.222.103: icmp: echo reply seq 141
11:47:11.507820 192.168.222.102 > 195.135.220.3: icmp: echo request seq 15
11:47:12.464524 192.168.222.103 > 195.135.220.3: icmp: echo request seq 142
11:47:12.487608 195.135.220.3 > 192.168.222.103: icmp: echo reply seq 142
...

So it seems, that the remote host does not reply.

Please note, when I ping from Dom0 *and* from one of the DomU''s at the
same time,
it works fine. Just en excerpt from tcpdump in this case.

11:56:19.338397 192.168.222.103 > 195.135.220.3: icmp: echo request seq 254
11:56:19.360969 195.135.220.3 > 192.168.222.103: icmp: echo reply seq 254
11:56:19.930122 192.168.222.16 > 195.135.220.3: icmp: echo request seq 12
(DF)
11:56:19.953969 195.135.220.3 > 192.168.222.16: icmp: echo reply seq 12
11:56:20.338293 192.168.222.103 > 195.135.220.3: icmp: echo request seq 255
11:56:20.367243 195.135.220.3 > 192.168.222.103: icmp: echo reply seq 255
11:56:20.934662 192.168.222.16 > 195.135.220.3: icmp: echo request seq 13
(DF)
11:56:20.971703 195.135.220.3 > 192.168.222.16: icmp: echo reply seq 13
11:56:21.353869 192.168.222.103 > 195.135.220.3: icmp: echo request seq 256
11:56:21.388060 195.135.220.3 > 192.168.222.103: icmp: echo reply seq 256
11:56:21.937585 192.168.222.16 > 195.135.220.3: icmp: echo request seq 14
(DF)
11:56:21.960194 195.135.220.3 > 192.168.222.16: icmp: echo reply seq 14

However, I will investigate this at a later moment.

Thanks
Wolfgang

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