OS/2 Tips: Connecting an OS/2 LAN to the Internet

by Sharif Abdallah

Overview
Creating a cost-effective link between your home office or small business LAN has never been easier.

By combining the features in OS/2 Warp with readily available free- and share-ware products users can be up and running quickly. I hope that this information gives you some ideas of just how easy it is to connect your home or small office LAN to the internet. If you have any other questions regarding the software that I describe in this site or about configuration issues, please drop me a note.

Regards,

Sharif Abdallah

Design Specifications
The following criteria were used in determining the resources used in creating the internet gateway:


 * Access to E-mail and WWW Resources
 * Sensitive Data must be Protected
 * Potential Damage must be Limited

Implementation
The key elements to impelmenting this solution are:

Never run a HTTP Proxy Server on your File Server
 * Physical Separation of the Servers

Make 'hacking' into the File Server difficult
 * Separate Protocols for the Servers

Notice that the Servers are NOT physically or logically connected!

Software Selection
Fortunately, OS/2 Warp (Connect and above) provides all of the basic tools necessary for establishing TCP/IP-based communications. Since TCP/IP is the basic internet communications protocol, all we have to do is put together a set of tools that let us accomplish the following tasks:


 * 1) Provide POP and SMTP services for local e-mail clients
 * 2) Provide proxy HTTP services for local web-browsers
 * 3) Control access to the communications channel

There are numerous shareware and freeware solutions available. What I've chosen to use are the following applications:


 * Inet.Mail - to provide e-mail services
 * Internet Connection Server - to provide proxy HTTP services
 * InJoy - to control the dialup connection

Server Configuration
Since both E-mail hosting and Proxy services are not CPU-intensive tasks, your choice of hardware is quite flexible. However, to get reasonable performance, I suggest the following minimum specifications:


 * CPU: 486DX/33 or better
 * RAM: at least 16MB (ICS 'Secure' requires 24MB)
 * Hard Disk: at least 100MB free space (after OS/2 installation)
 * Modem: 28.8 Kbps or better

When installing the software, keep in mind the following issues:


 * 1) When installing OS/2, install only the TCP/IP protocol and NOT the LAN Requestor. This helps protect your network from unauthorized access via the internet.
 * 2) Use the Dial-on-Demand and Auto-Disconnect features of the dialer to physically sever your internet connection when not in use. This provides yet another level of security against unauthorized access.
 * 3) Install the Internet Connection Server (ICS) as a proxy server and enable the cache option. See sample 'httpd.cnf'. The Internet Connection Server MUST be run from a HPFS partition.
 * 4) Automate the retrieval of new mail messages upon each connection by using INet.Mail's 'fetcher' command along with a customized REXX script. See sample 'fstore.cmd'

Client Configuration
Since the 'Server' uses standard protocols there are no special requirements for LAN clients. In general, the following type of clients will work:

(ex. OS/2, UNIX, Win9?, Win3.x, etc.)
 * Operating System: Any OS with TCP/IP services

(ex. PostRoad Mailer, PMMail, NotesMail, Netscape, etc.)
 * Mail Reader: POP3 and SMTP compliant

(ex. Netscape, WebExplorer, MSExplorer, etc.)
 * Browser: Any browser capable of specifying a proxy server

As with most configurations, you have to have enough RAM to avoid excessive swapping. A reasonable MINIMUM amount of RAM is 8MB. You will get far better response with a 16MB system.

InJoy v1.0 - Complete dialer application.
FX Communications, Brolaeggerstraede 12, DK-4300 Holbaek, Denmark Also available from BMT Micro. Cost: approximately $35.00

Inet.Mail v1.17a - POP3 and SMTP Mail Server.
 The authors also have an add-on 'fetcher' that allows you to fetch messages from a single ISP mail account. To use this you also must download the helper DLLs: HRxMail.dll and HRxPass.dll

Hethmon Brothers Also available from BMT Micro. Cost: $35.00 for 10 users

Internet Connection Server v4.2 - Full-featured HTML server (beta version).
IBM Internet Products Group Cost: Beta version free. Full 'unsecured' product $90 from Indellible Blue.