Server Fault is a question and answer site for system and network administrators. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

We trying a Xen server, and have a very strange issue, one that never happened to us on open-source Xen.

The VM's created on Xen do not see the network outside the host. They do can ping each other and host, and the host can ping them, but that all.

Any idea what causing this? I posted a question on Citrix forum but so far didn't receive a clear reply.

Thanks in advance!

share|improve this question
They're not on a internal-only network by any chance, are they? – tombull89 Oct 18 '11 at 13:41
This is an office network with standard Cisco router, which acts a a gateway. The problem is that VM's can't even see physical machines in LAN. – SyRenity Oct 18 '11 at 13:51
Plase try update network adpter firmware. i have the same problem, and after i updated the 10GB network adapter the problem solved. – user225940 Jun 12 '14 at 8:48

Probably you attached the VM's to an internal bridge. Point XenCEnter at yur server and look at the network definition. Xenserver's environment is considerably different from Xensource's, so do not exepect that (operation-wise) what applies to the latter will apply to the former and viceversa.

share|improve this answer
Hi. I have two networks on the XenServer, one active and one not. When I look at VM network, it sits on the active connection - though the IP address is marked as "unknown". Could this be related? – SyRenity Oct 20 '11 at 11:09
I can't say about the "unknown" address, though it does not appear to be significant (if the VMs ping each other, than they have IP adddresses alright). The issue about the connections is not active/unactive, rather public/private: what (if anything) is doing the bridging/routing/natting for that network? If the answer is "nothing", they won't be able to go outside that segment. – Alien Life Form Oct 20 '11 at 13:16
Hi. Do you mean natting/bridging on XenServer or the LAN itself? Because the LAN has router, the problem is that VM's can't even see other physical machines in the LAN, nor the router. – SyRenity Oct 21 '11 at 19:28
Xen allows you to set up "isolated" network. Machines on that networks, will see each other and (maybe) the Dom0 - period. So unless yo arrange for the Dom0 (that's the Xen Server) to connect that internal network (e.g. by bridging/natting/routing) those nodes will never be able to get out. – Alien Life Form Oct 27 '11 at 14:26
up vote 0 down vote accepted

The solution suggested on Citrix forums was pretty simple - connect network cable to second NIC, and move all machines to it.

Surprisingly, it helped.

share|improve this answer

protected by Tom O'Connor Jun 12 '14 at 9:38

Thank you for your interest in this question. Because it has attracted low-quality or spam answers that had to be removed, posting an answer now requires 10 reputation on this site (the association bonus does not count).

Would you like to answer one of these unanswered questions instead?

Not the answer you're looking for? Browse other questions tagged or ask your own question.