Re: [Xen-users] Strange Networking Issue

[Jonathon Jones <xen@xxxxxxxxxx>]

Martin Hierling wrote:

Jonathon,

To answer your question about eth0 vs. eth1, on the dom0 eth1 has the public IP but the below dump from ip addr list was on the domU showing that the .242 IP was added to the domU in the same way as the .240 IP however  .240 reaches the domU and .242 does not.

Yes, pingable means from the outside world.  Otherwise I will specify for clarity.

No firewalls.

Other services are also unreachable.

tcpdump was a great tip, thanks.  I'll add that to my tool belt.  The dom0 is receiving the ping request for .242 but that IP is added to the domU.  The domU is receiving the ping request for .240 however.

does DomU send an answer? Does the echo-reply package leaves Dom0 network interface. in bridged mode dump the traffic on your bridge interface, you should see all traffic there.

This is on Dom0:
[root@trinity ~]# tcpdump -i eth1 icmp
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on eth1, link-type EN10MB (Ethernet), capture size 96 bytes
13:10:10.473696 IP c-24-7-246-141.hsd1.in.comcast.net > trinity.pjlhosting.com: icmp 64: echo request seq 20
13:10:10.498042 IP trinity.pjlhosting.com > c-24-7-246-141.hsd1.in.comcast.net: icmp 64: echo reply seq 20
13:10:11.479154 IP c-24-7-246-141.hsd1.in.comcast.net > trinity.pjlhosting.com: icmp 64: echo request seq 21
13:10:11.479205 IP trinity.pjlhosting.com > c-24-7-246-141.hsd1.in.comcast.net: icmp 64: echo reply seq 21
13:10:12.476770 IP c-24-7-246-141.hsd1.in.comcast.net > trinity.pjlhosting.com: icmp 64: echo request seq 22
13:10:12.476779 IP trinity.pjlhosting.com > c-24-7-246-141.hsd1.in.comcast.net: icmp 64: echo reply seq 22
13:10:13.480174 IP c-24-7-246-141.hsd1.in.comcast.net > trinity.pjlhosting.com: icmp 64: echo request seq 23
13:10:13.480200 IP trinity.pjlhosting.com > c-24-7-246-141.hsd1.in.comcast.net: icmp 64: echo reply seq 23
13:10:17.853919 IP c-24-7-246-141.hsd1.in.comcast.net > pjlhosting.com: icmp 64: echo request seq 0
13:10:18.853326 IP c-24-7-246-141.hsd1.in.comcast.net > pjlhosting.com: icmp 64: echo request seq 1
13:10:19.860218 IP c-24-7-246-141.hsd1.in.comcast.net > pjlhosting.com: icmp 64: echo request seq 2
13:10:20.858329 IP c-24-7-246-141.hsd1.in.comcast.net > pjlhosting.com: icmp 64: echo request seq 3

12 packets captured
12 packets received by filter
0 packets dropped by kernel

That is what I see when I first ping the dom0 IP and then ping the .242 IP which is bound to Dom1.

I get the same thing when I watch the bridge.

Jon

You made the following statement which I don't understand: "Another thing is that your gateway/Dom0 ip is looking exactly like a transfer network, 75.126.153.176/29 for routing purpose. You should get some information from your provider how exactly the routing setup is."

Sorry, wrong netmask, it should be /30. This is a small network (only 2 hosts) between 2 routers. So the setup should be as followed:

INET  --> x.x.173.177/30  --> x.x.173.178/30 ---------> x.x.174.240/29
                ^provider Router     ^ your Router (Dom0)    ^ your DomU

So this small network is only used to transfer data between 2 routers.
provider router has a router for x.x.174.240/29 pointing to your Dom0 (173.178)

Martin

So are you saying I should change my netmasks from what I have?  I am not really getting what your suggestion is....sorry if I'm being dense.

Jon

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