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
$97.67
Apple Inc.
+0.64
MSFT
$44.50
Microsoft Corpora
+0.10
GOOG
$589.02
Google Inc.
-4.33

MacTech Search:
Community Search:

Software Updates via MacUpdate

TinkerTool 5.3 - Expanded preference set...
TinkerTool is an application that gives you access to additional preference settings Apple has built into Mac OS X. This allows to activate hidden features in the operating system and in some of the... Read more
Audio Hijack Pro 2.11.0 - Record and enh...
Audio Hijack Pro drastically changes the way you use audio on your computer, giving you the freedom to listen to audio when you want and how you want. Record and enhance any audio with Audio Hijack... Read more
Intermission 1.1.1 - Pause and rewind li...
Intermission allows you to pause and rewind live audio from any application on your Mac. Intermission will buffer up to 3 hours of audio, allowing users to skip through any assortment of audio... Read more
Autopano Giga 3.6 - Stitch multiple imag...
Autopano Giga allows you to stitch 2, 20, or 2,000 images. Version 3.0 integrates impressive new features that will definitely make you adopt Autopano Pro or Autopano Giga: Choose between 9... Read more
Airfoil 4.8.7 - Send audio from any app...
Airfoil allows you to send any audio to AirPort Express units, Apple TVs, and even other Macs and PCs, all in sync! It's your audio - everywhere. With Airfoil you can take audio from any... Read more
Microsoft Remote Desktop 8.0.8 - Connect...
With Microsoft Remote Desktop, you can connect to a remote PC and your work resources from almost anywhere. Experience the power of Windows with RemoteFX in a Remote Desktop client designed to help... Read more
xACT 2.30 - Audio compression toolkit. (...
xACT stands for X Aaudio Compression Toolkit, an application that encodes and decodes FLAC, SHN, Monkey’s Audio, TTA, Wavpack, and Apple Lossless files. It also can encode these formats to MP3, AAC... Read more
Firefox 31.0 - Fast, safe Web browser. (...
Firefox for Mac offers a fast, safe Web browsing experience. Browse quickly, securely, and effortlessly. With its industry-leading features, Firefox is the choice of Web development professionals... Read more
Little Snitch 3.3.3 - Alerts you to outg...
Little Snitch gives you control over your private outgoing data. Track background activityAs soon as your computer connects to the Internet, applications often have permission to send any... Read more
Thunderbird 31.0 - Email client from Moz...
As of July 2012, Thunderbird has transitioned to a new governance model, with new features being developed by the broader free software and open source community, and security fixes and improvements... Read more

Latest Forum Discussions

See All

New Trailer For Outcast Odyssey, A New K...
New Trailer For Outcast Odyssey, A New Kind of Card Battler Posted by Jennifer Allen on July 25th, 2014 [ permalink ] Out this Fall is a new kind of card battle game: Outcast Odyssey. | Read more »
Garfield: Survival of the Fattest Coming...
Garfield: Survival of the Fattest Coming to iOS this Fall Posted by Jennifer Allen on July 25th, 2014 [ permalink ] Who loves lasagna? Me. Also everyone’s favorite grumpy fat cat, Garfield. | Read more »
Happy Flock Review
Happy Flock Review By Andrew Fisher on July 25th, 2014 Our Rating: :: HERD IT ALL BEFOREUniversal App - Designed for iPhone and iPad Underneath the gloss of Happy Flock’s visuals is a game of very little substance. It’s cute, but... | Read more »
Square Register Updates Adds Offline Pay...
Square Register Updates Adds Offline Payments Posted by Ellis Spice on July 25th, 2014 [ permalink ] Universal App - Designed for iPhone and iPad | Read more »
Looking For Group – Hearthstone’s Curse...
For the first time since its release (which has thankfully been a much shorter window for iPad players than their PC counterparts), Blizzard’s wildly successful Hearthstone: Heroes of Warcraft CCG is sporting some brand new content: the single... | Read more »
Poptile Review
Poptile Review By Jennifer Allen on July 25th, 2014 Our Rating: :: SIMPLY FUNUniversal App - Designed for iPhone and iPad Simple yet a little bit glorious, Poptile is a satisfying entertaining puzzle game with oodles of the ‘one... | Read more »
Modern Combat 5: Blackout Review
Modern Combat 5: Blackout Review By Brittany Vincent on July 25th, 2014 Our Rating: :: LESS QQ, MORE PEW PEWUniversal App - Designed for iPhone and iPad The fifth entry into the blockbuster Modern Combat series is what mobile... | Read more »
Watch and Share Mobile Gameplay Videos W...
Watch and Share Mobile Gameplay Videos With Kamcord Posted by Jennifer Allen on July 25th, 2014 [ permalink ] iPhone App - Designed for the iPhone, compatible with the iPad | Read more »
THE KING OF FIGHTERS '98 (Games)
THE KING OF FIGHTERS '98 1.0 Device: iOS Universal Category: Games Price: $3.99, Version: 1.0 (iTunes) Description: Series’ masterpiece “KOF ’98” finally joins the battle on iPhone! FEATURES:■ The best game balance in the “KOF”... | Read more »
LEX Goes Free For One Day In Honor of Ne...
LEX Goes Free For One Day In Honor of New Update Posted by Jennifer Allen on July 24th, 2014 [ permalink ] Universal App - Designed for iPhone and iPad | Read more »

Price Scanner via MacPrices.net

iMacs on sale for $150 off MSRP, $250 off for...
Best Buy has iMacs on sale for up to $160 off MSRP for a limited time. Choose free home shipping or free instant local store pickup (if available). Prices are valid for online orders only, in-store... Read more
Mac minis on sale for $100 off MSRP, starting...
Best Buy has Mac minis on sale for $100 off MSRP. Choose free shipping or free instant local store pickup. Prices are for online orders only, in-store prices may vary: 2.5GHz Mac mini: $499.99 2.3GHz... Read more
Global Tablet Market Grows 11% in Q2/14 Notwi...
Worldwide tablet sales grew 11.0 percent year over year in the second quarter of 2014, with shipments reaching 49.3 million units according to preliminary data from the International Data Corporation... Read more
New iPhone 6 Models to Have Staggered Release...
Digitimes’ Cage Chao and Steve Shen report that according to unnamed sources in Apple’s upstream iPhone supply chain, the new 5.5-inch iPhone will be released several months later than the new 4.7-... Read more
New iOS App Helps People Feel Good About thei...
Mobile shoppers looking for big savings at their favorite stores can turn to the Goodshop app, a new iOS app with the latest coupons and deals at more than 5,000 online stores. In addition to being a... Read more
Save on 5th generation refurbished iPod touch...
The Apple Store has Apple Certified Refurbished 5th generation iPod touches available starting at $149. Apple’s one-year warranty is included with each model, and shipping is free. Many, but not all... Read more
What Should Apple’s Next MacBook Priority Be;...
Stabley Times’ Phil Moore says that after expanding its iMac lineup with a new low end model, Apple’s next Mac hardware decision will be how it wants to approach expanding its MacBook lineup as well... Read more
ArtRage For iPhone Painting App Free During C...
ArtRage for iPhone is currently being offered for free (regularly $1.99) during Comic-Con San Diego #SDCC, July 24-27, in celebration of the upcoming ArtRage 4.5 and other 64-bit versions of the... Read more
With The Apple/IBM Alliance, Is The iPad Now...
Almost since the iPad was rolled out in 2010, and especially after Apple made a 128 GB storage configuration available in 2012, there’s been debate over whether the iPad is a serious tool for... Read more
MacBook Airs on sale starting at $799, free s...
B&H Photo has the new 2014 MacBook Airs on sale for up to $100 off MSRP for a limited time. Shipping is free, and B&H charges NY sales tax only. They also include free copies of Parallels... Read more

Jobs Board

*Apple* Solutions Consultant (ASC) - Apple (...
**Job Summary** The ASC is an Apple employee who serves as an Apple brand ambassador and influencer in a Reseller's store. The ASC's role is to grow Apple Read more
*Apple* Solutions Consultant (ASC) - Apple (...
**Job Summary** The ASC is an Apple employee who serves as an Apple brand ambassador and influencer in a Reseller's store. The ASC's role is to grow Apple Read more
Sr. Project Manager for *Apple* Campus 2 -...
…the design and construction of one building or building components of the New Apple Campus located in Cupertino, CA. They will provide project management oversight for Read more
WW Sales Program Manager, *Apple* Online St...
**Job Summary** Imagine what you could do here. At Apple , great ideas have a way of becoming great products, services, and customer experiences very quickly. Bring Read more
*Apple* Solutions Consultant (ASC) - Apple (...
**Job Summary** The ASC is an Apple employee who serves as an Apple brand ambassador and influencer in a Reseller's store. The ASC's role is to grow Apple Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.