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

rudiahlers at gmail.com rudiahlers at gmail.com
Sun Aug 10 13:00:02 UTC 2008

Just an update on this, when I add x.x.136.105 to the domU, and ran
nmap on that IP, the IRC ports are open, so that confirms my "theory"
- this is then a routing issue between the dom0 & domU, right? But how
do I fix it?

On 8/10/08, rudiahlers at gmail.com <rudiahlers at gmail.com> wrote:
> 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


Kind Regards
Rudi Ahlers

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