IGNITe/400 Mailing List Archive Entry

We are starting to stretch my knowledge of AS/400 IP routing a bit
here. But, I'll give a whirl anyway.

Is what you want to happen is to have all 10.x.x.x traffic to go over
one NIC (call this NIC1), and ALL other traffic over the other (Call
this NIC2)?

How many PC's and other devices do you have on your network?

If the number is large, you probably don't want to readdress your
network. But, if the number is small, how does this sound:

Set your internet router to

Use the 10.1.1.x network for all of your users. Have them use a
subnet mask of and a default gateway address of

On your /400, NIC1 (local trafic), give it an IP of 10.1.1.something
with a subnet mask of This will force all local
traffic over this NIC.

For NIC2, give it an IP of and a subnet of

On the /400, your default route should be

With this setup, all local traffic will go over NIC1

All Internet traffic will go over NIC2

Since all other systems think 10.1.1.something and are in the
same network (net mask, the will be able to talk to
either the router or the /400. I suspect (from what you say), that
you should NOT have the pc's talk to (NIC2 of the /400),
because it will come in over NIC2 but go out over NIC1 (I think?) and
this might confuse token ring. But this shouldn't be hard to do.

And yes, it is Ok to have mixed subnet masks. I've done it at Support
Net. However, it is not "Normal", but it can solve problems. It is
definitely "out of the box thinking". I've had arguments with
academics over this entire issue.

Let me know if it works!

Bob Crothers
Cornerstone Communications, LLC

-----Original Message-----
Ignite400 Members List [SMTP:ign_list@ignite400.org]
Sent: Thursday, July 30, 1998 12:58 AM
To: Ignite400 Members List Mailing List
RE: Multiple Interfaces Under 370

Bleddyn Williams

Hi Bob the interfaces on the 400 are all on the same network we just
to physically separate the traffic so make use of the two TR cards.
Both use
an Internal 10 class to cover all the offices and I don't think under
this can be done? I wanted to analyse the traffic coming in from the
offices without having any effect from internal devices such as NC's.
think we will have to run a big LAN till they upgrade to V420 in the

Thanks Bleddyn

-----Original Message-----
ign_list@ignite400.org [mailto:ign_list@ignite400.org]
Sent: 29 July 1998 15:42
To: Ignite400 Members List Mailing List
RE: Multiple Interfaces Under 370

Bob Crothers


The 2 NIC's should be on different networks based on the IP address
and Subnet masks. Correct?

The default route should be pointing (next hop address) at an IP
address (of a router or routing device) in the same network as one of
the NIC's. This probably is your internet router. Everything should
then go over that NIC.

You can then setup routings for the networks on the other NIC so stuff
that goes over routers on that segment will get thru.

At least, this is how I understand the AS/400 static routings.


-----Original Message-----
Ignite400 Members List [SMTP:ign_list@ignite400.org]
Sent: Wednesday, July 29, 1998 1:40 PM
To: Ignite400 Members List Mailing List
Multiple Interfaces Under 370

Bleddyn Williams

Don't know if anyone has seen this or knows a way to get round it but
have been working with a customer who has two token ring cards in the
On one we have separated it of with a separate MAU's to point to
network with its own router while the other connects the local office
the Internet connection to the 400.

They both run TCP/IP but the problem is there is no way to define a
route to
an interface and what is happening is that IP wants to send traffic
down the
wrong side. So it thinks the default route is down the non Internet
connection and promptly starts sending all packets down there. Now on
when you ping it sends the request out to the network and you are then
unable to ping any of the interfaces sitting on the local office side.
very strange and a pain I can see with 420 and 430 you can bind a
route to
an interface but how can we get round it on V370?

Thanks Bleddyn

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