On Monday, 01/26/2009 at 01:31 EST, Mark Pace <[email protected]> wrote:
> Yes, that is exactly what I'm saying.  But I thought I had asked that 
question 
> before and that the z9 took care of that problem.

Yes, you did ask.  On the z890 and up (with reasonably current OSA 
microcode) layer 2 and layer 3 are visible to each other.  If they weren't 
you couldn't ping.  (BTW, Cisco switches will not echo a broadcast back to 
the same port on which it was received.)

If you can ping, but you can't do a DNS lookup or ftp, then something else 
is at work.  I would get a tcpdump (whether in the DNS guest or ftp guest) 
to see if they are the hosts that are being contacted.  You may want to 
get a virtual sniffer trace via another guest with the extra authority to 
enter promiscuous mode.

I note that DNS and FTP are "upper" TCP/UDP protocols while ping is a 
low-level IP protocol.  If it were a new host, I'd suspect the imbedded 
firewall in the Linux guest.

Alan Altmark
z/VM Development
IBM Endicott

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