This setup won't work, because Linux negotiates its mac address with the OSA, and cannot send frames from another mac. You could use ip forwarding, and have Linux route on layer 3. This should work, as long as you use the OSA in layer 2 mode.
with kind regards
Carsten Otte
System z firmware development / Boeblingen lab
---
Every revolution was first a thought in one man's mind;
and when the same thought occurs to another man, it is the key to that era.
- Ralph Waldo Emerson, Essays: First Series, 1841
"Pavelka, Tomas"
<Tomas.Pavelka@ca
.com> To
Sent by: Linux on LINUX-390@vm.marist.edu,
390 Port cc
<linux-...@vm.mar
ist.edu> Subject
Layer 2 frames passing through a
Linux bridge get dropped before
20.02.2014 09:04 leaving the mainframe box
Please respond to
Linux on 390 Port
<linux-...@vm.mar
ist.edu>
We have a problem where frames that pass through a Linux bridge do not
reach the gateway outside of the mainframe box. We have set up an
experiment that reproduces the problem, which looks like this:
(LINUX1) - <private vswitch> - (LINUXBR) - <public vswitch> - OSA - gateway
The problem is that in this setup we cannot ping the gateway. But, under a
different setup:
(LINUX1) - <private vswitch> - (LINUXBR) - <public vswitch> - (LINUX2)
Both LINUX1 and LINUX2 can communicate. Moreover, LINUX2 can ping the
gateway (the OSA card is still connected to the public vswitch, I just did
not put it in the picture).
Some more details that may be important:
- Both public and private vswitch are layer 2
- LINUXBR runs RHEL 6 and uses bridge-utils to create the bridge
- private vswitch is not connected to any OSA card
We have played with TCPDUMP and found that ARP (broadcast) packets do reach
the gateway and come back, but ping's ICMP (unicast) packets get dropped.
This led us to the following hypothesis: If there is a unicast packet
originating from a MAC address not known to public vswitch, it gets dropped
somewhere on the way between LINUXBR and the gateway.
Does anyone know any settings that could affect filtering done either by
the vswitch or by the OSA card? We asked our hardware people but they did
not know of anything that could cause the problems. But a more targeted
question could help if we knew what to ask for.
Any debugging tips will be much appreciated.
Thanks,
Tomas
Tomas Pavelka
CA Technologies
Sr Software Engineer
Tel: +420226207796
tomas.pave...@ca.com
<mailto:tomas.pave...@ca.com>[cid:image001.gif@01CF2E1A.CF9FFDB0]<
http://www.ca.com/>
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