Re: [Xen-users] can't get NAT to a VM on domU working

["Hardy Wolf" <hardy@xxxxxxxxxxxxxxxx>]

The XEN-Script I am using. But only to switch to nat.

I did only overwrite the firewall rules. It works without them. But security isn't the important thing in my configuration, because in my dom0 won't run any services.

 

Greets,

Hardy

----- Original Message -----

From: Roberto Saccon

To: Hardy Wolf

Sent: Saturday, April 22, 2006 8:51 PM

Subject: Re: [Xen-users] can't get NAT to a VM on domU working

Thanks Hardy, I will give your scritpt a try. However I have one question: Did you not use the xen networkd scripts (/etc/xen/xend-config.sxp) at all or did you just overwrite their firewall rules ?

regards
Roberto

On 4/22/06, Hardy Wolf < hardy@xxxxxxxxxxxxxxxx> wrote:

Hi,

 

I am using nat in XEN 3.0.1 and it works.

I have one dom0 and one domU, but I think it will work for more domUs, too.

 

I have a iptables-script, that runs on every bootup:

 

 

========== SNIP ==========

#!/bin/bash
ipt=/sbin/iptables

 

extip=72.232.68.66

 

$ipt -F -t nat
$ipt -F
$ipt -P FORWARD ACCEPT
$ipt -P INPUT ACCEPT
$ipt -P OUTPUT ACCEPT

 

echo "1" > /proc/sys/net/ipv4/ip_forward

 

# SSH

$ipt -t nat -A PREROUTING -d $extip -p tcp --dport 22 -j DNAT --to 10.0.0.3

# FTP

$ipt -t nat -A PREROUTING -d $extip -p tcp --dport 21 -j DNAT --to 10.0.0.3

# FTP-Passive Ports
$ipt -t nat -A PREROUTING -d $extip -p tcp --dport 10001:10020 -j DNAT --to 10.0.0.3

 

$ipt -t nat -A POSTROUTING -s 10.0.0.0/24 -j MASQUERADE

========== SNAP ==========

 

That's it.

 

If you want to change the destination port (i.e. --to 10.0.0.3:22), I think it will work, too.

 

Important are the lines

 -> echo "1" ...

ans

 -> ... MASQUERADE

 

So any network traffic to outside is possible and inbound traffic for the specified ports.

 

This script has a further function: The lines beginning with "$ipt -F" will first delete all existing rules and then overwrite with the new ones. So you can upgrade your script with a further rule (or delete a rule) and run it without any connection loss.

--
Roberto Saccon

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