WARNING - OLD ARCHIVES

This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
   
 
 
Xen 
 
Home Products Support Community News
 
   
 

xen-users

[Xen-users] Problems using NAT in Xen 3.0

To: xen-users@xxxxxxxxxxxxxxxxxxx
Subject: [Xen-users] Problems using NAT in Xen 3.0
From: Roberto Virga <rvirga@xxxxxxxxxxxxxxxxxxxxx>
Date: Wed, 07 Sep 2005 14:50:33 +0200
Delivery-date: Wed, 07 Sep 2005 13:10:10 +0000
Envelope-to: www-data@xxxxxxxxxxxxxxxxxxx
List-help: <mailto:xen-users-request@lists.xensource.com?subject=help>
List-id: Xen user discussion <xen-users.lists.xensource.com>
List-post: <mailto:xen-users@lists.xensource.com>
List-subscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-users>, <mailto:xen-users-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-users>, <mailto:xen-users-request@lists.xensource.com?subject=unsubscribe>
Reply-to: rvirga@xxxxxxxxxxxxxxxxxxxxx
Sender: xen-users-bounces@xxxxxxxxxxxxxxxxxxx
User-agent: KNode/0.9.2
I'm trying to set up Xen 3.0 unstable on my machine(Athlon 64 X2 4200+,
running FC4/x86_64), and almost everything works well except domU
networking. Since connection to the internet is through an ADSL modem
(ppp0), I decided to use NAT rather than bridging. I used the network-nat
and vif-nat scripts from the tools/examples, changing 'eth0' with 'ppp0'.
Networking works somewhat, but with huge packet loss depending on the
protocols. Specifically, ping and ftp work without any problem. ssh
connections and dns lookups take a very long time to respond (~1 min.), but
eventually get a response, so not all the packets get lost. This is
particularly problematic with DNS, since lookups time out before they get a
response from the servers, and the way I found out they get a response at
all is to manually run 'telnet <DNS_server_IP> 53'.
This happens regardless if I try to connect to the internet or to just dom0,
which makes me believe it's not a problem with the IP tables configuration
(I've tried setting up a DNS server on dom0, with the same effect).
I've noticed the following odd thing running 'ip addr':

> 1: lo: <LOOPBACK,UP> mtu 16436 qdisc noqueue
>     link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
>     inet 127.0.0.1/8 scope host lo
> 2: vif0.0: <BROADCAST,MULTICAST> mtu 1500 qdisc noop
>     link/ether fe:ff:ff:ff:ff:ff brd ff:ff:ff:ff:ff:ff
> 3: veth0: <BROADCAST,MULTICAST> mtu 1500 qdisc noop
>     link/ether 00:00:00:00:00:00 brd ff:ff:ff:ff:ff:ff
> 4: eth0: <BROADCAST,MULTICAST,UP> mtu 1500 qdisc pfifo_fast qlen 1000
>     link/ether 00:13:d4:33:8c:71 brd ff:ff:ff:ff:ff:ff
> 6: vif1.0: <BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue
>     link/ether fe:ff:ff:ff:ff:ff brd ff:ff:ff:ff:ff:ff
>     inet 192.168.1.1/24 brd 192.168.1.255 scope global vif1.0
> 7: ppp0: <POINTOPOINT,MULTICAST,NOARP,UP> mtu 1492 qdisc pfifo_fast qlen 3
>     link/ppp
>     inet 82.52.83.171 peer 192.168.100.1/32 scope global ppp0

In the above, vif0.0 (what's this for, anyway?) and vif1.0 have the same MAC
address (fe:ff:ff:ff:ff:ff), which it cannot be good. I've tried setting a
different MAC using the 'be_mac' option in the domU configuration file:

> vif = [ 'mac=aa:00:00:00:00:11, be_mac=aa:00:00:00:00:22,
ip=192.168.1.1/24' ]

but the option is ignored and the MAC is always set to fe:ff:ff:ff:ff:ff
regardless.

So my questions:
1. Has anybody managed to use Xen 3.0 unstable with NAT?
2. How do I set the MAC of the vif<n>.0 interfaces?
3. Do any of you have any suggestions of things I could try in order to
   diagnose/fix this problem? (I'm a newbie at Linux networking :-))

Thanks in advance for your help,

- Roberto



_______________________________________________
Xen-users mailing list
Xen-users@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-users

<Prev in Thread] Current Thread [Next in Thread>