On Tuesday, 09/16/2003 at 09:49 CST, Matt Lashley/SCO
<[EMAIL PROTECTED]> wrote:
> I have three Linux images coupled to a VSWITCH.  The VSWITCH is
connected
> to an OSA Express.  The OSA Express is plugged into a VLAN on a Cisco
6509
> which is plugged into a PIX with an IP address if 172.16.64.1
>
> The Linux images have IP addresses in the 192.168.2.0/24 subnet.  The
PIX
> does NAT for the images.
>
> Everything works fine for a few hours and then -- POOF! -- the Linux
images
> seem to lose all communication.  I've queried the VSWITCH when things
are
> good and when things are bad (Q VSWITCH DET).  I've also looked at the
OSA
> OAT table using OSA/SF.  Everything looks the same whether things are
> working or not.  When things are not working one of the LAN guys watched
a
> PING from the one of teh Linux images to the PIX and it looks like
> everything is working fine to him.  The PIX gets the PING and replies
back
> but the response never makes it back to the Linux image.
>
> Besides the VSWITCH there is a Hipersockets Guest LAN with a Linux image
> that routes packets to OS/390 via CTC for Tivoli backups.  Could this
> router image that is not connected to the VSWICTH be causing a problem?
> Everything seemed to work together fine for about five hours.  (When I
say
> router image I mean a very basic static routing image with
> /proc/sys/net/ipv4/ip_forward set to '1')
>
> Anyway, I'm looking for more ways to troubleshoot this.  A picture of
the
> environment is here: http://164.165.56.143/~XAS9585/CommEx.jpg
>
> The VSWITCH was set to NONROUTER.

I don't think the CTC has anything to do with it, esp. if everyone is
using a static route.

When you say "... the response never makes it back to the Linux image", is
that information based on a sniffer sitting between the OSA and the
switch?  If not, you need to do that.  If the packet is being delivered to
OSA, you will need a matching tcpdump on Linux that demonstrates that the
packet was not delivered to Linux.

At that point, contact the Support Center.

Alan Altmark
Sr. Software Engineer
IBM z/VM Development

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