Some of you may have read my article on configuring the NAT at www.ignite400.org in the Evelyn Porter Institute section of the web site, tried it out, and had
difficulties. I sent several hours with the NAT developer over the past couple of days and the issues are routing.
Assume the following:
You are mapping a public address 18.104.22.168 defined to the AS/400 via an Ethernet adapter to a private address 10.11.20.70 defined on a token ring
adapter. You configure an IBM HTTP Server with bind specific=YES on 10.11.20.70.
You then define mapping rules as I illustrated in the article and enable the NAT.
You can't access your web server.
The issue is now a routing issue. This is what is going on.
1. An IP packet comes in to the machine via the internet from say 22.214.171.124 addressed to 126.96.36.199
2. The NAT intercepts the packet and changes the TO address from 188.8.131.52 to 10.11.20.70.
3. The HTTP server gets the request and processes.
4. The HTTP server formats the request and sends it to 184.108.40.206
IF you do not have a route defined on your AS/400 to your public Internet router, the packet gets stuffed in the big bit bucket in the SKY!
You must define a default route pointing to your Internet router for this to work. You then need subnet routes pointing to your internal LAN router
so that your internal traffic (on the 10... subnet) is routed properly. Once the routing is worked out NAT works like a dream!