Logo: TUG TORONTO USERS GROUP for Midrange Systems
e -server magazine

May 1997: Volume 11, Number 5

Communicating with Sam

TCP/IP for AS/400

By Sam Johnston

From the questions submitted, the selected issue to be addressed in this issue is:


y company has recently begun investigating the Internet, and your article in the last edition of the TUG Newsletter was timely. Also, I was considering utilizing the TCP/IP support for the AS/400 for PC network communications. I believe there can be some management benefits in migrating to a single network protocol. Given the information in your article regarding IP addressing, are there any risks I should be aware of prior to implementing TCP/IP on the AS/400?


any companies have recently started moving to TCP/IP for AS/400 and PC communications. Fundamentally this is a technology strategy issue that should be carefully considered based upon the benefits of the technology in supporting your business objectives. The most common business strategy that drives this technology is the decision to make the Internet integral to your business operations.

From a pure technology perspective, the benefits are as follows:

The management savings that you can recognize will vary with the size of your network. In our experience, small and even most medium sized networks cannot justify the investment unless there are specific business needs that drive the pay-back.

The largest risk or cost associated with this decision is the increased resource load on the AS/400. The native protocol for the AS/400 remains SNA even when moving to TCP/IP for communications. Deploying TCP/IP for communications will result in the need to convert SNA 5250 screens to TCP/IP, and this requires additional resources.

A key advantage to OS/400 and the SNA protocol is security. However, permitting TCP/IP into the AS/400 and providing the AS/400 with an IP address, especially when it involves an Internet connection, will significantly reduce security. TCP/IP is a common protocol used in Open Systems around the world, and in providing the AS/400 with an IP address, there are now millions of users that can attach and hack the AS/400.

You may be able to address this issue via security products, but this may counter any benefits derived from reduced complexity at the desk top.

At the end of the day, this is a business decision. You will need to assess whether the technology benefits of pursuing this strategy are justified given the serious security issues that you are now introducing into your network. In my experience, the security and resource issues are only justified when the Internet and telnetting provide a significant business advantage. T < G

Note: Any TUG member wishing to submit a question to Sam can e-mail or forward their typewritten material to the TUG office, or to Intesys. We would be pleased to publish your question and Sam's answer in an upcoming issue of the TUG/400 e-server magazine.