[CentOS] can't access irc server on xen domU, please help

rudiahlers at gmail.com rudiahlers at gmail.com
Sun Aug 10 12:55:30 UTC 2008

Hey Kai,

I just made an interesting discovery. As I said in my previous post,
the domU is running on a different subnet from the dom0 - and although
the traffic from the dom0 to the domU doesn't travel via a switch, it
does seem like this is causing a problem

The dom0 is on x.x.136.110/27 (x.x.136.97 = default gw) and the domU
is on x.x.136.55/27 (x.x.136.33 = default gw)
The subnet mask on both are

The server connects to a switch, and then to a firewall on the
internet. The network firewall itself has 4 WAN ports, and 4 different
subnets. For a fact, I know I can't communicate with a host from one
subnet, to a host on another subnet, since the network firewall
doesn't allow it.

So, I have a feeling this affect the networking on the Xen server as
well, even if I take the network firewall out of the picture.

How do I work with a XEN domU on a different subnet than the XEN dom0?

On 8/10/08, Kai Schaetzl <maillists at conactive.com> wrote:
> Rudiahlers at gmail.com wrote on Sun, 10 Aug 2008 14:11:06 +0200:
>> >> 443/tcp  closed https
> sorry, I dind't look close enough. "closed", of course, means closed ;-)
> Did you disable firewall for testing on *every* host that is involved
> (e.g. on the hosts you try to access/run nmap from), including the
> gateway? Is this the only IRC service you have running? I'd rather guess
> you don't have a xen problem, but simply block that port somewhere on the
> way, and be it on your gateway. Running tcpdump on every involved host may
> help.
> Kai
> --
> Kai Schätzl, Berlin, Germany
> Get your web at Conactive Internet Services: http://www.conactive.com
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Kind Regards
Rudi Ahlers

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