Re: IP Addressing. Was(CAE - client ip address)

Jeff wrote . . .
<        In this case while the issue may be that the return packet is
lost.
I believe the problem is routing on the source system.  In every IP Packet
is the Source IP and Target IP address of a the Packet. When the host
processes that Packet it uses the source address as the new Target for the
return Packet.
        If NIC2 is to be the target then it should also be the source.  To
force this add an explicit route to the system from a command line with the
route cmd, add function so that packets leaving the PC for the AS/400 and
it's subnet, will always leave from and return to NIC2.   By the way, if
the
outbound packet from your PC is NAT translated by a router/firewall then
the
AS/400 will see the adddress of the NAT box not the NIC regardless of which
NIC you leave on.>

Hi Jeff,
there was only 1 NIC involved, but it had 2 ip addresses (diff subnets)
assigned to it.
Routing out from the client to the gateway was not a problem (seen on
traces I'm told)
The same gateway had 2 ip addresses (the same 2 subnets)

This CAE is at our FM web site and uses JDBC to pull data from the 400
There were major sub-net network changes made inside our network which
triggered this

I was told that our changed routers/firewall would not find their old
return address and that they had added a second address to the same NIC
which was supposed to be routable by our network.
I was then asked me how to configure CAE to force it to use this new
secondary NIC address as the origin (source) address
I couldn't find any online references

Anyway, they tried fiddling with Dos ROUTE entries with no luck. Then they
installed a second NIC with just that one new address and changed the PC
routing to use that NIC to route to us (at least thats what they told me).
That didn't work either and they went back to one NIC.
They assure me the packets get to the 400 , just not back.

The final solution is to use NAT at their end but for some reason that
can't be done for two weeks.
The current workaround is to add some static route entries to our routers
to allow for the return address they are using.

Most of the above is second or third hand so I can't vouch for its accuracy
.
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Regards,        Rod Orr