[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

[Xen-users] (vif-route) DomU IP troubles beyond Dom0

To: xen-users@xxxxxxxxxxxxxxxxxxx
From: Piers Dawson-Damer <piersdd@xxxxxxxxxxxxx>
Date: Sat, 1 Apr 2006 02:07:31 +1100
Delivery-date: Mon, 03 Apr 2006 09:50:44 -0700
List-id: Xen user discussion <xen-users.lists.xensource.com>

Hello All,

Having read these posts over and over again I find myself in the same position as many with DomU routing.

Trying to keep the configuration as simple (default) as possible, I have tried what feels like every permutation of configuration.

It would be great if somebody could confirm/clear up this for me; (from http://wiki.xensource.com/xenwiki/XenNetworking)

When domU starts up, xend runs (within dom0) vif-route which:

1. copies the ip address from eth0 to vif<id#>.0 (with a 32 bit subnet mask 255.255.255.255)

2. brings up vif<id#>.0 (which seams to be on a different subnet, but there really are no subnets with 32 bit masks)

3. adds host static route for domU's ip address specified in domU config file, pointing at interface

(which relies on proxyarp)

So, is proxyARP essential for routing with point-to-point 32 bit mask links, or only Xen routing?

With a configured DomU on a seperate subnet to Dom0's eth0, with vif ['ip=10.9.0.1'] and with Dom0's default route set to dev eth0

DomU can ping Dom0 on 10.1.0.254/16, but cannot ping real host 10.1.0.253/16 (DSL masq. router) on the same physical/logical network. Nor two other MacOS X hosts, but get this, it can ping yet another host 10.1.0.239/16 on the physical/logical network. That host, has under some Dom0/DomU configuration permutation of hours gone, connected via ssh to DomU.

This leads me to think the problem must be within Dom0's routing/forwarding/ARPing.

So DomU routing table is;

DomU# route

Kernel IP routing table

Destination Gateway Genmask Flags Metric Ref Use Iface

loopback localhost 255.0.0.0 UG 0 0 0 lo

default * 0.0.0.0 U 0 0 0 eth0

Dom0# route

Kernel IP routing table

Destination Gateway Genmask Flags Metric Ref Use Iface

10.9.0.1 * 255.255.255.255 UH 0 0 0 vif6.0

10.1.0.0 * 255.255.0.0 U 0 0 0 eth0

default 10.1.0.253 0.0.0.0 UG 0 0 0 eth0

Seams fine. As I can ping real host 10.1.0.239/16, does this mean the routing is OK?

If so, is it an ARP blip?

Dom0# arp

Address HWtype HWaddress Flags Mask Iface

10.1.0.253 ether 00:05:5D:9F:87:0E C eth0

10.9.0.1 ether 00:16:3E:28:B6:BD C vif6.0

Dom0.someip.net ether 00:16:CB:85:35:4E C eth0

10.1.0.239 ether 00:B0:D0:AD:A3:E4 C eth0

DomU# arp

Address HWtype HWaddress Flags Mask Iface

10.1.0.254 ether FE:FF:FF:FF:FF:FF C eth0

203.0.178.191 ether FE:FF:FF:FF:FF:FF C eth0

10.1.0.239 ether FE:FF:FF:FF:FF:FF C eth0

10.1.0.253 ether FE:FF:FF:FF:FF:FF C eth0

I tried deleting both arp entries, then pinging, but they re-appear.

Firewalling? I have Shorewall installed, but not enabled, nor run.

Some odd kernel compilation? Dunno. Will recompile as vanilla in the morning.

Others on this list seamed to have suffered this.

links:

http://lists.xensource.com/archives/html/xen-users/2006-03/msg00953.html

http://lists.xensource.com/archives/html/xen-users/2006-02/msg00229.html

Mooktakim Ahmed has it working, although I cannot replicate.

http://lists.xensource.com/archives/html/xen-users/2006-03/msg00949.html

I also note that if vif [ 'vifname=vifabc.0' ] is specified, there is no Net0 RX:.... displayed within xentop

vif = [ 'ip=10.9.0.1' ]

xentop - 00:40:47 Xen 3.0.1

2 domains: 1 running, 1 blocked, 0 paused, 0 crashed, 0 dying, 0 shutdown

Mem: 2096640k total, 552644k used, 1543996k free CPUs: 4 @ 3189MHz

NAME STATE CPU(sec) CPU(%) MEM(k) MEM(%) MAXMEM(k) MAXMEM(%) VCPUS NETS NETTX(k) NETRX(k) SSID

Domain-0 -----r 33 0.1 131196 6.3 no limit n/a 4 8 0 0 0

Net0 RX: 0bytes 0pkts 0err 0drop TX: 0bytes 0pkts 0err 0drop

Net1 RX: 0bytes 0pkts 0err 0drop TX: 0bytes 0pkts 0err 0drop

Net2 RX: 0bytes 0pkts 0err 0drop TX: 0bytes 0pkts 0err 0drop

Net3 RX: 0bytes 0pkts 0err 0drop TX: 0bytes 0pkts 0err 0drop

Net4 RX: 0bytes 0pkts 0err 0drop TX: 0bytes 0pkts 0err 0drop

Net5 RX: 0bytes 0pkts 0err 0drop TX: 0bytes 0pkts 0err 0drop

Net6 RX: 0bytes 0pkts 0err 0drop TX: 0bytes 0pkts 0err 0drop

Net7 RX: 0bytes 0pkts 0err 0drop TX: 0bytes 0pkts 0err 0drop

DomU --b--- 11 0.0 393160 18.8 393216 18.8 4 1 0 0 0

Net0 RX: 126bytes 3pkts 0err 0drop TX: 42bytes 1pkts 0err 0drop

vif = [ 'ip=10.9.0.1,vifname=vif-eu.0' ]

xentop - 00:44:11 Xen 3.0.1

2 domains: 1 running, 1 blocked, 0 paused, 0 crashed, 0 dying, 0 shutdown

Mem: 2096640k total, 552668k used, 1543972k free CPUs: 4 @ 3189MHz

NAME STATE CPU(sec) CPU(%) MEM(k) MEM(%) MAXMEM(k) MAXMEM(%) VCPUS NETS NETTX(k) NETRX(k) SSID

Domain-0 -----r 38 0.1 131196 6.3 no limit n/a 4 8 0 0 0