TweetFollow Us on Twitter

Oct 99 Online

Volume Number: 15 (1999)
Issue Number: 10
Column Tag: MacTech Online

MacTech Online

by Jeff Clites <online@mactech.com>

Last month we started looking into some resources that can help you in setting up a small network, such as a home network to connect a few computers and printers. We found out that you can often cut your expenses by using an old Macintosh in place of new dedicated hardware, in this case to let you network a non-network printer, or expose a LocalTalk printer to an Ethernet network. Not only did we save some cash by using an old Mac, but also we made it possible to print from Mac OS X Server on a Blue and White G3, despite the limited connectivity options that platform currently supports. This month we're going to see how to use a single IP address to connect multiple machines to the outside world, again using an older Mac to do the real work.

Learning to Share: Network Address Translation

It's a pretty common problem - you only have one IP address available, but now you have more than one computer. So, you have to decide which one gets to use the modem, DSL line, or cable modem, or else you end up switching off and having to do a lot of plugging and unplugging of cables. Although it seems as though it shouldn't be possible, you actually can let all of your computers access the outside world at once through this single public IP address, thanks to a protocol known as Network Address Translation (NAT). In a nutshell, you assign arbitrary "private" IP addresses to the machines on your local network, and all communication to the outside world goes through a gateway machine (which can be a computer or a dedicated hardware device), which translates the source address in the header of the outgoing packets to your single public IP address, and it makes a note of this. Then, it reverses the process on incoming reply packets, so that they arrive at the proper local machine.

NAT is a capability built into most firewall products, and there are hardware devices which can act essentially as black boxes and do NAT for you, such as SonicWALL, BeadleNet's firewall routers, and Macsense's XRouter. These devices tend to be simple to set up and use, but are overkill if you just want to share an IP address - they are designed to do much more than just NAT, and their prices reflect this. A software-based approach is more economical, and it continues my theme of taking advantage of your legacy Macs. Both Vicomsoft and Sustainable Softworks have software solutions which perform NAT. Vicomsoft has several different products which include this along with their other functionality, but I chose IPNetRouter from Sustainable Softworks: there is no limit imposed on the number of computers you can connect through a single gateway, and it is low-cost (it is priced at $89), in part because it is simpler and a little more do-it-yourself. Also, there is a 50% educational discount available. I'm going to focus on IPNetRouter here, but you may want to check out the competition (both software- and hardware-based) for yourself.

SonicWALL
<http://www.sonicwall.com/>
BeadleNet
<http://www.beadlenet.com/>
Macsense XRouter
<http://www.macsensetech.com/Product/mih120.html>
Vicomsoft
<http://www.vicomsoft.com/>
Sustainable Softworks
<http://www.sustworks.com/>

Although IPNetRouter can seem a bit cryptic at first, if you just want to do NAT there are clear instructions on the company's web site, and you'll be up and running in just a few minutes. Your gateway machine can use either one or two Ethernet cards, and there are instructions on how to set up either configuration. The two-card setup is conceptually easier to understand, and offers a bit more security: one card connects to your local network and the other connects to the outside, so no information about your internal network configuration can leak to the outside world without going through IPNetRouter. Ethernet cards are cheap, so you may want to opt for this setup.

Getting Started with IPNetRouter
<http://www.sustworks.com/products/ipnr/gettingstarted/Guide.html>

This brings up another benefit of NAT: your gateway machine acts in part as a firewall, hiding your internal network from the outside world. In fact, from the outside it will appear as though there is only a single computer involved. This, in itself, makes it difficult to break into your internal computers; your private LAN can access the public internet, but not the other way around. If you want to go a little further and add some additional security measures, Sustainable Softworks has a page entitled Building Your Own Low Cost Firewall which will help you set up IPNetRouter for this. Finally, you can do almost the opposite, and "punch a hole" in your configuration to allow, for instance, a web server to operate from inside of your network. To do this, you set up IPNetRouter to do inbound port mapping, which routes all traffic destined for a particular port at your public IP address to a particular port on a particular machine on your internal network. This allows machines on the public internet to initiate connections to your internal web server; they think they are connecting to, say, port 80 of your gateway machine, but really they are being served web pages from port 80 (or another port of your choosing) of in internal machine. You'll probably need to do similar port mapping to use the QuickTime Streaming Server (but client machines can receive streaming QuickTime 4 content without any special configuration - support for this is built-in).

Building Your Own Low Cost Firewall
<http://www.sustworks.com/products/ipnr/gettingstarted/firewall.html>
Port Mapping
<http://www.sustworks.com/products/ipnr/gettingstarted/port_mapping.html>

So, for less than $90 I can connect multiple computers to the internet, and set up firewall protection for a web server. That's not bad, and best of all, it's fast. In my home setup, I'm using a PowerMac 7500/150 as my gateway, and there's no noticeable slowdown compared to when my internal Mac is connected directly to my DSL line. Part of the reason that IPNetRouter is fast is that it is Open Transport native (in fact, most of its capabilities are built into Open Transport already, and IPNetRouter just provides a way to configure them). But you also have to remember that this isn't a computationally intensive task - I believe that Cisco routers still use 68K-based processors. So even an old 68K Mac should give pretty good performance.

The pages mentioned above do a pretty good job of introducing you to concepts such as NAT, firewalls, and port mapping. You can get some more information on NAT from the KnowledgeShare section of Vicomsoft's site, or you can go directly to the RFCs and get the details.

Vicomsoft KnowledgeShare: Network Address Translation
<http://www.vicomsoft.com/knowledge/reference/nat.html>
RFC1631 - The IP Network Address Translator (NAT)
<http://www.faqs.org/rfcs/rfc1631.html>
RFC2663 - IP Network Address Translator (NAT) Terminology and Considerations
<http://www.faqs.org/rfcs/rfc2663.html>

So, again we've found a strategy that lets us use a spare Macintosh to save us the expense of buying new hardware to set up our network, adding IP sharing to our bag of tricks to go along with the printer sharing techniques we learned last month. Also, we've again solved a problem that developers will be especially likely to face: even if you plan to use only a single computer, if you are using Mac OS X Server then you currently need a second IP address in order to access the internet from the Blue Box. With a NAT setup this is no longer a problem, and you can use last month's printing trick at the same time by running Apple's LocalTalk Bridge on your gateway along with IPNetRouter - they seem to play well together.

As a final note, when you run into snags you should check out the Three Macs and a Printer web site, which contains a wealth of information about setting up a small network, and explains everything in simple terms. It covers many topics that I have not been able to touch upon, and it has recently settled in to its very own domain.

Three Macs & a Printer
<http://www.threemacs.com/network/index.html>

When you get tired of connecting everything together, take a gander at the other links available from the MacTech Online web pages at <www.mactech.com/online/>.

 
AAPL
$103.30
Apple Inc.
+0.80
MSFT
$45.09
Microsoft Corpora
-0.34
GOOG
$577.33
Google Inc.
+5.73

MacTech Search:
Community Search:

Software Updates via MacUpdate

TextSoap 7.4.0 - Flexible text editing u...
TextSoap is for people who work with text. TextSoap effortlessly cleans up text from endlessly different formats. Wash away unwanted characters, spaces, tabs. Fix paragraphs with hard returns at the... Read more
NetShade 6.0.2 - Browse privately using...
NetShade is an Internet security tool that conceals your IP address on the web. NetShade routes your Web connection through either a public anonymous proxy server, or one of NetShade's own dedicated... Read more
Mac DVDRipper Pro 5.0 - Copy, backup, an...
Mac DVDRipper Pro is the DVD backup solution that lets you protect your DVDs from scratches, save your batteries by reading your movies from your hard disk, manage your collection with just a few... Read more
pwSafe 3.1 - Secure password management...
pwSafe provides simple and secure password management across devices and computers. pwSafe uses iCloud to keep your password databases backed-up and synced between Macs and iOS devices. It is... Read more
StatsBar 1.8 - Monitor system processes...
StatsBar gives you a comprehensive and detailed analysis of the following areas of your Mac: CPU usage Memory usage Disk usage Network and bandwidth usage Battery power and health (MacBooks only)... Read more
Path Finder 6.5.5 - Powerful, award-winn...
Path Finder is a file browser that combines the familiar Finder interface with the powerful utilities and innovative features. Just a small selection of the Path Finder 6 feature set: Dual pane... Read more
QuarkXPress 10.2.1 - Desktop publishing...
With QuarkXPress, you can communicate in all the ways you need to -- and always look professional -- in print and digital media, all in a single tool. Features include: Easy to Use -- QuarkXPress is... Read more
Skype 6.19.0.450 - Voice-over-internet p...
Skype allows you to talk to friends, family and co-workers across the Internet without the inconvenience of long distance telephone charges. Using peer-to-peer data transmission technology, Skype... Read more
VueScan 9.4.41 - Scanner software with a...
VueScan is a scanning program that works with most high-quality flatbed and film scanners to produce scans that have excellent color fidelity and color balance. VueScan is easy to use, and has... Read more
Cloud 3.0.0 - File sharing from your men...
Cloud is simple file sharing for the Mac. Drag a file from your Mac to the CloudApp icon in the menubar and we take care of the rest. A link to the file will automatically be copied to your clipboard... Read more

Latest Forum Discussions

See All

Modern Combat 5 Gets a Major Multiplayer...
Modern Combat 5 Gets a Major Multiplayer Update Posted by Jessica Fisher on September 2nd, 2014 [ permalink ] Universal App - Designed for iPhone and iPad | Read more »
Alien Creeps TD Review
Alien Creeps TD Review By Jennifer Allen on September 2nd, 2014 Our Rating: :: EXPENSIVE DEFENSESUniversal App - Designed for iPhone and iPad Alien Creeps TD would be a fun if unremarkable Tower Defense game, but its heavy focus on... | Read more »
The Journey Down: Chapter Two Review
The Journey Down: Chapter Two Review By Jennifer Allen on September 2nd, 2014 Our Rating: :: DARK YET ENTICINGUniversal App - Designed for iPhone and iPad It’s a little dark, in every sense of the word, but The Journey Down:... | Read more »
Function Space, a Social Network App for...
Function Space, a Social Network App for Science, Launches on iOS Posted by Ellis Spice on September 2nd, 2014 [ permalink ] | Read more »
Stupidfast – How Taylor Martinez Switche...
How do you make an Endless Running game more than just another Endless Running game? By adding real life prizes to it, of course! That’s the thinking behind StupidFast: a game designed for football enthusiasts, and the brainchild of former college... | Read more »
Little Raiders: Robin’s Revenge Review
Little Raiders: Robin’s Revenge Review By Jennifer Allen on September 2nd, 2014 Our Rating: :: CASUAL RAIDINGUniversal App - Designed for iPhone and iPad Combining simple combat with village building is a potent combination for... | Read more »
Treasure Tombs: Ra Deal Coming from Bulk...
Treasure Tombs: Ra Deal Coming from Bulkypix and Dark Tonic This Fall Posted by Jessica Fisher on September 2nd, 2014 [ permalink ] Dark Tonic and | Read more »
Pirate Bash Review
Pirate Bash Review By Nadia Oxford on September 2nd, 2014 Our Rating: :: BAD PIRATES, GOOD TIMESUniversal App - Designed for iPhone and iPad Pirate Bash’s turn-based battles add an intriguing twist to a typical physics game.   | Read more »
Tiny Tower Vegas Review
Tiny Tower Vegas Review By Jennifer Allen on September 2nd, 2014 Our Rating: :: STEADY DEVELOPMENTUniversal App - Designed for iPhone and iPad Build a huge tower again but Vegas-style in Tiny Tower Vegas.   | Read more »
The Manhattan Project Review
The Manhattan Project Review By Andrew Fisher on September 2nd, 2014 Our Rating: :: ROCKET SCIENCEUniversal App - Designed for iPhone and iPad The Manhattan Project offers a great Euro-style gameplay experience, but it is totally... | Read more »

Price Scanner via MacPrices.net

Apple refurbished iPads available for up to $...
Apple is offering Certified Refurbished iPad Airs for up to $140 off MSRP. Apple’s one-year warranty is included with each model, and shipping is free. Stock tends to come and go with some of these... Read more
Are We Now In The Post-Post-PC Era?
A longtime and thoroughgoing laptop aficionado, I was more than a little dismayed by Steve Jobs’s declaration back in 2010 when he sprang the iPad on an unsuspecting world. that we’d entered a “post-... Read more
PC Outlook Improves, But 2014 Shipments Still...
According to the International Data Corporation (IDC) Worldwide Quarterly PC Tracker, worldwide PC shipments are expected to fall by -3.7 percent in 2014. To hat’s actually an improvement from the... Read more
IDC Lowers Tablet Sales Projections for 2014...
Following a second consecutive quarter of softer than expected demand, International Data Corporation (IDC) has lowered its worldwide tablet plus 2-in-1 forecast for 2014 to 233.1 million units. The... Read more
Apple now offering refurbished 21-inch 1.4GHz...
The Apple Store is now offering Apple Certified Refurbished 21″ 1.4GHz iMacs for $929 including free shipping plus Apple’s standard one-year warranty. Their price is $170 off the cost of new models,... Read more
Save $50 on the 2.5GHz Mac mini, on sale for...
B&H Photo has the 2.5GHz Mac mini on sale for $549.99 including free shipping. That’s $50 off MSRP, and B&H will also include a free copy of Parallels Desktop software. NY sales tax only. Read more
Save up to $300 on an iMac with Apple refurbi...
The Apple Store has Apple Certified Refurbished iMacs available for up to $300 off the cost of new models. Apple’s one-year warranty is standard, and shipping is free. These are the best prices on... Read more
The Rise of Phablets
Carlisle & Gallagher Consulting Group, a businesses and technology consulting firm focused solely on the financial services industry, has released an infographic depicting the convergence of... Read more
Bad Driver Database App Allows Good Drivers t...
Bad Driver Database 1.4 by Facile Group is a new iOS and Android app that lets users instantly input and see how many times a careless, reckless or just plain stupid driver has been added to the... Read more
Eddy – Cloud Music Player for iPhone/iPad Fre...
Ukraine based CapableBits announces the release of Eddy, its tiny, but smart and powerful cloud music player for iPhone and iPad that allows users to stream or download music directly from cloud... Read more

Jobs Board

*Apple* Retail - Multiple Positions (US) - A...
Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, you're also the Read more
*Apple* Retail - Multiple Positions (US) - A...
Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, you're also the Read more
*Apple* Retail - Multiple Positions (US) - A...
Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, you're also the Read more
*Apple* Retail - Multiple Positions (US) - A...
Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, you're also the Read more
Senior Event Manager, *Apple* Retail Market...
…This senior level position is responsible for leading and imagining the Apple Retail Team's global event strategy. Delivering an overarching brand story; in-store, Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.