RE: Grumble... -- MIDRANGE-L

Joe,

        As an experiment, can you configure your router to NAT 216.36.82.12 <->
10.1.1.60 ?  Not just port 80.  Sure sounds like something within the
router.  Some routers / switches / firewalls need their ARP caches flushed
when there are several config changes happening.  I suspect the link between
the ouside world an the AS/400 needs more than port 80.

        Alex

-----Original Message-----
From: owner-midrange-l@midrange.com
[mailto:owner-midrange-l@midrange.com]On Behalf Of Joe Pluta
Sent: Sunday, February 25, 2001 10:28 PM
To: MIDRANGE-L@midrange.com
Subject: RE: Grumble...


Sorry folks.  I'll try to give complete information this time.

My AS/400 has an address of 10.1.1.60.  My workstation is 10.1.1.20, my NT
server 10.1.1.100 and my router 10.1.1.17.  My Linux machine is 10.1.1.70.

My router is a Netopia, and it happily allows all of my devices to
communicate with the external world through my DSL line.  All that is,
except for the AS/400.  Now to answer some of your specific questions:

"1. Can you ping your router from your AS/400 and from your NT Machines?"

Yes.  All machines ping one another quite nicely.  The AS/400 actually
serves web pages quite well within the LAN.


"2. What is the internal IP address of your AS/400 and what is the subnet
that you are using?"

As I said, the internal address is 10.1.1.60.  The subnet I use on each of
the machines is 255.255.255.0.


"3. Are you pinging by IP Address or domain name?"

IP address.  Since the AS/400 cannot get out to the real world, its cannot
access DNS servers either.  So I am attempting to ping *INTNETADR, and this
is failing as well.



"You also said that you are trying to do webserving with your AS/400.  Is
this internal or external? If external, you will need to have your firewall
or router convert your external address to your internal address.  Can you
ping the AS/400 from your NT? DId you start the webserver on the AS/400?
You can start the admin server and try to connect to it..
http://ipaddress:2001/  to see if it is working."

This is exactly what I am trying to do, but it is not working.  I use my
router to map address for port 80 to my AS/400 (address 10.1.1.60), and it
doesn't work (although the AS/400 is serving pages internally perfectly).  I
change the router to map port 80 to address 10.1.1.100 (the NT server) and
it works - the copy of WebSphere running on the NT server serves up pages
perfectly.  So the AS/400 is doing something differently than the NT server.

Now, on the NT server I have to set my gateway to 10.1.1.17.  On the AS/400,
there is something called the default route, which I've also set to
10.1.1.17.  Once I did that, the AS/400 was able to communicate inside the
LAN, but it still will not send packets past the router.

Here's the interesting bit:

With the Netopia configured to pass port 80 to 10.1.1.60:

1. Inside the LAN, a request to 10.1.1.60:80 gets pages from the AS/400.
2. Inside the LAN, a request to 216.36.82.12:80 (the router's realworld
address), gets pages from the AS/400.
3. Requests from outside the LAN to 216.36.82.12:80 get no response.

With the Netopia configured to pass port 80 to 10.1.1.100:

1. Inside the LAN, a request to 10.1.1.60:80 gets pages from the AS/400.
2. Inside the LAN, a request to 216.36.82.12:80 (the router's realworld
address), gets pages from the NT server.
3. Requests from outside the LAN to 216.36.82.12:80 get pages from the NT
server.


"       Your 10.1.1.* address needs a router or firewall or some means of being
"routed" or "natted" to an external public address.  Normally ( is there
such a thing ) you would have all of your private addresses inside of a
firewall.  Your firewall might translate, via NAT, your 10. private address
to an external and public address.  Your router may also perform this
function."

This is what the Netopia is doing.  I followed the instructions on the
Netopia site, and as I've explained, it works perfectly for the NT server.
It's just not passing the data from the AS/400.  Is it something to do with
IP forwarding or one of those other arcane TCP/IP switch settings?


"Do you know how to run a comm trace on your AS/400?  Do you have one of the
downloadable TRACERT utilities for the AS/400?  Is your one and only route
active?  A process called dead gateway processing will make your route
inactive for a period of time if your next hop cannot be pinged by the
AS/400."

No, no, yes.  I did the NETSTAT, and it shows this:

      Route            Subnet           Next               Route
 Opt  Destination      Mask             Hop              Available
      10.1.1.0         255.255.255.0    *DIRECT            *YES
      127.0.0.0        255.0.0.0        *DIRECT            *YES
      224.0.0.0        240.0.0.0        *DIRECT            *YES
      224.0.0.0        240.0.0.0        *DIRECT            *YES
      *DFTROUTE        *NONE            10.1.1.17          *YES

Not sure about the 224.0.0.0/240.0.0.0 entries - there's one for 10.1.1.60
and one for 127.0.0.1.  The interesting thing is it's now taking a long time
to do an option 5 on those routes - a do an option 5 and NETSTAT goes into
SELW for about 30 or 40 seconds (it wasn't doing this before).

Next thing is, I'm going to shut down TCP/IP and bring it back up again.  I
hate doing this, because I inevitably screw up the servers and then nothing
works.  But I'm going to give it a shot.  I'll also look into getting a
TRACERT utility from somewhere.  I saw something about it, can't remember
where.


Joe

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