Running IAK and LAN TCP/IP Simultaneously--Security Issue

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Last update: 6th November, 1995

Symptoms

Running attached to a 3rd party Internet access provider while simultaneously running TCP/IP locally on a LAN.

Hardware

Any

Problem

INET.SYS provides routing capabilities by default. This is a potential security issue which could allow unauthorized access to an otherwise secure network.

Procedure

At the command line type "IPGATE OFF". This command should be put in the startup.cmd file to ensure it is in effect whenever the two TCP/IP networks are both up and running. IPGATE.EXE is provided in the IAK.

Notes

The suggested way of handling IP addressing and name resolution when simultaneously accessing TCP/IP via the LAN and IAK is to use IP addresses for LAN access and names for IAK access. However, you may be able to keep multiple etc directories--the default for the IAK and another for LAN access, the resolv file in the second etc would point to your local DNS servers. Start the apps doing local access by using .cmd files which change the default ETC environmental value. Note: The IAK will save and restore a resolve file when the use the IAK dialer to connect and disconnect from the Internet.

If security is not an issue, other machines on your LAN can access the Internet through an OS/2 machine that is running the IAK and LAN TCP/IP by defining that OS/2 box as a router in their local setup.

Thanks to IBM's John McGarvey and the OS2BBS for the information on IPGATE.

Matt Hickman