Mailing List Archive

Networking domU > Internet ping gives "destination host unreachable"
Hello @all,

thanks for all the helpfull answers in this mailing list. They helped me
compiling a new kernel 2.6.10.11 with Xen 2.0.6 (my first one), setting
up a dom0 with RAID, LVM and loop devices for domU, integrating a second
network as xen-br1 (I'm calling the /etc/xen/scripts/network script from
within /etc/init.d/xend to bring up / down the second bridge.) and
bootstrapping my domU VMM.

But finally I got stuck just before the goal.

When in my dom0 I can ping successfully any computer on the same subnet
and any web server (e. g. www.heise.de)
But in my domU I can only ping the internal computers. Pinging a
web-server gives me an "destination host unreachable", even though he
can transform a DNS-name into the IP-adress, but thats probably because
of my own DNS on 192.168.10.2.

That's the result of ping in domU:
rc_manager:~# ping www.heise.de
PING www.heise.de (193.99.144.85) 56(84) bytes of data.
#From 192.168.250.1 icmp_seq=1 Destination Host Unreachable
From 192.168.250.1 icmp_seq=2 Destination Host Unreachable
From 192.168.250.1 icmp_seq=3 Destination Host Unreachable
From 192.168.250.1 icmp_seq=5 Destination Host Unreachable
From 192.168.250.1 icmp_seq=6 Destination Host Unreachable
From 192.168.250.1 icmp_seq=7 Destination Host Unreachable

--- www.heise.de ping statistics ---
8 packets transmitted, 0 received, +6 errors, 100% packet loss, time 7027ms
, pipe 3


A few words on the network topology:
192.168.10.1 is gateway to internet
dom0 and domU are DHCP-Clients in 192.168.10.x network

I have two networkcards in my xen-machine:
eth0 is connect to the 192.168.10.x net
eth1 is not used at the moment (domU will be DNS/DHCP/NFS Server for a
new subnet 192.168.250.x with fixed domU fixed IP 192.168.10.1 and dom0
fixed IP 192.168.250.2)

Might there be a problem with MACs of domU (look at the end of this
mail). Once I read something with first byte of MAC address and
multicast modus or something?
Or does domU mix up the two nics? (Don't think so.)

I hope you can give me some advice where to look at.

Regards,
Mario Minati


In the following I paste infomation on the network configuration.

*dom0*

xen-001:~# ifconfig
eth0 Protokoll:Ethernet Hardware Adresse 00:50:04:F6:01:82
inet Adresse:192.168.10.246 Bcast:192.168.10.255
Maske:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:964 errors:0 dropped:0 overruns:0 frame:0
TX packets:395 errors:0 dropped:0 overruns:0 carrier:0
Kollisionen:0 Sendewarteschlangenlänge:1000
RX bytes:128050 (125.0 KiB) TX bytes:56409 (55.0 KiB)
Interrupt:11 Basisadresse:0xe400

eth1 Protokoll:Ethernet Hardware Adresse 00:06:4F:18:0C:E1
inet Adresse:192.168.250.2 Bcast:192.168.250.255
Maske:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:30 errors:0 dropped:0 overruns:0 carrier:0
Kollisionen:0 Sendewarteschlangenlänge:1000
RX bytes:0 (0.0 b) TX bytes:1800 (1.7 KiB)
Interrupt:5 Basisadresse:0xa000

lo Protokoll:Lokale Schleife
inet Adresse:127.0.0.1 Maske:255.0.0.0
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:3577 errors:0 dropped:0 overruns:0 frame:0
TX packets:3577 errors:0 dropped:0 overruns:0 carrier:0
Kollisionen:0 Sendewarteschlangenlänge:0
RX bytes:391367 (382.1 KiB) TX bytes:391367 (382.1 KiB)

vif1.0 Protokoll:Ethernet Hardware Adresse FE:FF:FF:FF:FF:FF
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:207 errors:0 dropped:0 overruns:0 frame:0
TX packets:801 errors:0 dropped:0 overruns:0 carrier:0
Kollisionen:0 Sendewarteschlangenlänge:0
RX bytes:27421 (26.7 KiB) TX bytes:99617 (97.2 KiB)

vif1.1 Protokoll:Ethernet Hardware Adresse FE:FF:FF:FF:FF:FF
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:30 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
Kollisionen:0 Sendewarteschlangenlänge:0
RX bytes:1260 (1.2 KiB) TX bytes:0 (0.0 b)

xen-br0 Protokoll:Ethernet Hardware Adresse 00:50:04:F6:01:82
inet Adresse:192.168.10.246 Bcast:192.168.10.255
Maske:255.255.255.255
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:793 errors:0 dropped:0 overruns:0 frame:0
TX packets:198 errors:0 dropped:0 overruns:0 carrier:0
Kollisionen:0 Sendewarteschlangenlänge:0
RX bytes:87995 (85.9 KiB) TX bytes:26798 (26.1 KiB)

xen-br1 Protokoll:Ethernet Hardware Adresse 00:06:4F:18:0C:E1
inet Adresse:192.168.250.2 Bcast:192.168.250.255
Maske:255.255.255.255
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:30 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
Kollisionen:0 Sendewarteschlangenlänge:0
RX bytes:840 (840.0 b) TX bytes:0 (0.0 b)

xen-001:~# brctl show
bridge name bridge id STP enabled interfaces
xen-br0 8000.005004f60182 no eth0
vif1.0
xen-br1 8000.00064f180ce1 no eth1
vif1.1

xen-001:~# route -n
Kernel IP Routentabelle
Ziel Router Genmask Flags Metric Ref Use
Iface
192.168.250.0 0.0.0.0 255.255.255.0 U 0 0 0
xen-br1
192.168.10.0 0.0.0.0 255.255.255.0 U 0 0 0
xen-br0
0.0.0.0 192.168.10.1 0.0.0.0 UG 0 0 0
xen-br0

xen-001:~# iptables
iptables v1.2.11: no command specified
Try `iptables -h' or 'iptables --help' for more information.
xen-001:~# iptables --list
Chain INPUT (policy ACCEPT)
target prot opt source destination

Chain FORWARD (policy ACCEPT)
target prot opt source destination

Chain OUTPUT (policy ACCEPT)
target prot opt source destination


*domU*

rc_manager:~# ifconfig
eth0 Link encap:Ethernet HWaddr AA:00:00:00:01:00
inet addr:192.168.10.250 Bcast:192.168.10.255 Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:818 errors:0 dropped:0 overruns:0 frame:0
TX packets:210 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:101509 (99.1 KiB) TX bytes:27847 (27.1 KiB)

eth1 Link encap:Ethernet HWaddr AA:00:00:00:01:01
inet addr:192.168.250.1 Bcast:192.168.250.255 Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:30 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:0 (0.0 b) TX bytes:1260 (1.2 KiB)

lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:24 errors:0 dropped:0 overruns:0 frame:0
TX packets:24 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:2592 (2.5 KiB) TX bytes:2592 (2.5 KiB)

rc_manager:~# route -n
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use
Iface
192.168.250.0 0.0.0.0 255.255.255.0 U 0 0 0 eth1
192.168.10.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0
0.0.0.0 192.168.250.1 0.0.0.0 UG 0 0 0 eth1
0.0.0.0 192.168.10.1 0.0.0.0 UG 0 0 0 eth0


*domU Configuration*

xen-001:/etc/xen/auto# cat rc_manager
# -*- mode: python; -*-
kernel = "/boot/vmlinuz-2.6.11-xenU"
memory = 128
name = "rc_manager"
nics=2
vif = [ 'mac=aa:00:00:00:01:00, bridge=xen-br0', 'mac=aa:00:00:00:01:01,
bridge=xen-br1' ]
disk = [ 'file:/opt/xen/disks/rc_manager/main.loop,sda1,w',
'file:/opt/xen/disks/rc_manager/opt.loop,sda2,w',
'file:/opt/xen/disks/rc_manager/swap.loop,sda3,w' ]
root = "/dev/sda1 ro"
restart = 'onreboot'


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Re: Networking domU > Internet ping gives "destination host unreachable" [ In reply to ]
Mario Minati wrote:
> Hello @all,

> rc_manager:~# route -n
> Kernel IP routing table
> Destination Gateway Genmask Flags Metric Ref Use
> Iface
> 192.168.250.0 0.0.0.0 255.255.255.0 U 0 0 0
> eth1
> 192.168.10.0 0.0.0.0 255.255.255.0 U 0 0 0
> eth0
> 0.0.0.0 192.168.250.1 0.0.0.0 UG 0 0 0
> eth1
> 0.0.0.0 192.168.10.1 0.0.0.0 UG 0 0 0
> eth0
>
>

Looks like the kernel wants to get out at eth1.
Try to delete the default route at eth1,
IRC route del default gw 192.168.250.1 or try with Interface metrics.

HTH
Johannes


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Re: Networking domU > Internet ping gives "destination host unreachable" [ In reply to ]
Hello Johannes,

you saved my day :-)

I'm not experienced in that routing stuff, but I should have seen that
before...

The reason was in my /etc/network/interfaces

On the static definition of eth1 I had a gateway line, because I
misunderstood the meaning of it. After removing it, everything works
like a charm.

Thanks again,
Mario Minati

Johannes Puschmann schrieb:

>Mario Minati wrote:
>
>
>>Hello @all,
>>
>>
>
>
>
>>rc_manager:~# route -n
>>Kernel IP routing table
>>Destination Gateway Genmask Flags Metric Ref Use
>>Iface
>>192.168.250.0 0.0.0.0 255.255.255.0 U 0 0 0
>>eth1
>>192.168.10.0 0.0.0.0 255.255.255.0 U 0 0 0
>>eth0
>>0.0.0.0 192.168.250.1 0.0.0.0 UG 0 0 0
>>eth1
>>0.0.0.0 192.168.10.1 0.0.0.0 UG 0 0 0
>>eth0
>>
>>
>>
>>
>
>Looks like the kernel wants to get out at eth1.
>Try to delete the default route at eth1,
>IRC route del default gw 192.168.250.1 or try with Interface metrics.
>
>HTH
>Johannes
>
>
>_______________________________________________
>Xen-users mailing list
>Xen-users@lists.xensource.com
>http://lists.xensource.com/xen-users
>
>
>


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