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/>.

 

Community Search:
MacTech Search:

Software Updates via MacUpdate

Monolingual 1.6.4 - Remove unwanted OS X...
Monolingual is a program for removing unnecesary language resources from OS X, in order to reclaim several hundred megabytes of disk space. If you use your computer in only one (human) language, you... Read more
CleanApp 5.0 - Application deinstaller a...
CleanApp is an application deinstaller and archiver.... Your hard drive gets fuller day by day, but do you know why? CleanApp 5 provides you with insights how to reclaim disk space. There are... Read more
Fantastical 2.0 - Create calendar events...
Fantastical is the Mac calendar you'll actually enjoy using. Creating an event with Fantastical is quick, easy, and fun: Open Fantastical with a single click or keystroke Type in your event details... Read more
Cocktail 8.2 - General maintenance and o...
Cocktail is a general purpose utility for OS X that lets you clean, repair and optimize your Mac. It is a powerful digital toolset that helps hundreds of thousands of Mac users around the world get... Read more
Direct Mail 4.0.4 - Create and send grea...
Direct Mail is an easy-to-use, fully-featured email marketing app purpose-built for OS X. It lets you create and send great looking email campaigns. Start your newsletter by selecting from a gallery... Read more
jAlbum Pro 12.6 - Organize your digital...
jAlbum Pro has all the features you love in jAlbum, but comes with a commercial license. With jAlbum, you can create gorgeous custom photo galleries for the Web without writing a line of code!... Read more
jAlbum 12.6 - Create custom photo galler...
With jAlbum, you can create gorgeous custom photo galleries for the Web without writing a line of code! Beginner-friendly, with pro results Simply drag and drop photos into groups, choose a design... Read more
Lyn 1.5.9 - Lightweight image browser an...
Lyn is a lightweight and fast image browser and viewer designed for photographers, graphic artists and Web designers. Featuring an extremely versatile and aesthetically pleasing interface, it... Read more
Sublime Text 3080 - Sophisticated text e...
Sublime Text is a sophisticated text editor for code, markup, and prose. You'll love the slick user interface, extraordinary features, and amazing performance. Goto Anything. Use Goto Anything to... Read more
WALTR 1.0.11 - Drag-and-drop any media f...
WALTR is designed to make it easy to upload and convert any music or video file to an iPad or iPhone format for native playback. It supports a huge variety of media file types, including MP3, MP4,... Read more

WWE WrestleMania Tags into the App Store
Are You ready to rumble? The official WWE WrestleMania app, by World Wrestling Entertainment, is now available. Now you can get all your WrestleMania info in one place before anyone else. The app offers details on superstar signings, interactive... | Read more »
Bio Inc's New Expansion is Infectin...
Bio Inc., by DryGin Studios, is the real time strategy game where you infect a human body with the worst virus your evil brain can design. Recently, the game was updated to add a whole lot of new features. Now you can play the new “Lethal”... | Read more »
The Monocular Minion is Here! Despicable...
Despicable Me: Minion Rush, by Gameloft, is introducing a new runner to the mix in their latest update. Now you can play as Carl, the prankster minion. Carl has a few new abilities to play with, including running at a higher speed from the start.... | Read more »
Dungeon of Madness (Games)
Dungeon of Madness 1.0.0 Device: iOS Universal Category: Games Price: $1.99, Version: 1.0.0 (iTunes) Description: Dungeon of Madness is an action game where you rotate tiles to create our own route. Help the hero by connecting the... | Read more »
Filters for iPhone (Photography)
Filters for iPhone 1.0 Device: iOS iPhone Category: Photography Price: $.99, Version: 1.0 (iTunes) Description: | Read more »
Jump'N'Shoot Attack (Games)
Jump'N'Shoot Attack 1.0 Device: iOS Universal Category: Games Price: $1.99, Version: 1.0 (iTunes) Description: A mobile game for gamers! Join Louise Lightfoot, the legendary "Master of Jumping and Shooting", on her mission to save... | Read more »
Space Bounties Inc. (Games)
Space Bounties Inc. 1.4 Device: iOS Universal Category: Games Price: $1.99, Version: 1.4 (iTunes) Description: SuperGameDroid: 4/5 "Satisfying futuristic RPG combat, high replay value, and a heavy dose of nostalgia make Space... | Read more »
Gamebook: Pocket RPG (Games)
Gamebook: Pocket RPG 1.0.11 Device: iOS Universal Category: Games Price: $2.99, Version: 1.0.11 (iTunes) Description: Walk into the Land of Lanthir Lamath ruled by wicked skeletons and fight for your life in a thrilling adventure.... | Read more »
Kids Can Mix, Match, and Catch with Tata...
Tatadada MixMatch, by Tatadada Ltd, is a mobile version of the classic game of mix & match. The game uses brightly colored creatures to train your children's pattern matching skills and hand-eye coordination. It's aimed at children around age 5... | Read more »
The Trace: Murder Mystery Game (Games)
The Trace: Murder Mystery Game 1.2.0 Device: iOS Universal Category: Games Price: $4.99, Version: 1.2.0 (iTunes) Description: | Read more »

Price Scanner via MacPrices.net

Logitech Says MX Master Is Its Most Advanced...
Logitech’s new MX Master Wireless Mouse incorporates the best of Logitech’s many computer mouse innovations into a striking hand-sculpted design. The company claims that the MX Master creates a new... Read more
Save up to $300 on a new Mac, $30 on an iPad,...
Purchase a new Mac or iPad at The Apple Store for Education and take up to $300 off MSRP. All teachers, students, and staff of any educational institution qualify for the discount. Shipping is free,... Read more
Apple refurbished 2014 MacBook Airs available...
The Apple Store lowered prices on Apple Certified Refurbished 2014 MacBook Airs recently, with models now available starting at $679. An Apple one-year warranty is included with each MacBook, and... Read more
Mac Notebook Evolution; A Desktop Replacement...
More often than not right from the beginning, Apple’s Macs have tended to skew toward small. The original Macs were called “compacts,”, and notwithstanding a few exceptions like the honking Big Mac... Read more
13-inch 1.4GHz/128GB MacBook Air (Apple refur...
The Apple Store has Apple Certified Refurbished 2014 13″ 1.4GHz/128GB MacBook Airs available for $759 including free shipping plus Apple’s standard one-year warranty. Their price is $240 off original... Read more
YEP! Alternative Browser for iOS Now Supports...
Pfaeffikon, Switzerland based Power App AG has announced the release of an update to their Yep! Web Browser (v1.3.0) for iOS8 iPhone and iPad. Yep! hit the App Store shortly after the release of iOS... Read more
15-inch Retina MacBook Pros on sale for up to...
B&H Photo has the new 2014 15″ Retina MacBook Pros on sale for up to $250 off MSRP for a limited time. Shipping is free, and B&H charges NY sales tax only: - 15″ 2.2GHz Retina MacBook Pro: $... Read more
Clearance 13-inch Retina MacBook Pros availab...
B&H Photo has leftover 2014 13″ Retina MacBook Pros on sale for up to $250 off original MSRP. Shipping is free, and B&H charges NY sales tax only: - 13″ 2.6GHz/128GB Retina MacBook Pro: $1098... Read more
Clearance 2014 MacBook Airs on sale for up to...
B&H Photo has MacBook Airs on sale for up to $180 off original MSRP. Shipping is free, and B&H charges NY sales tax only: - 11″ 128GB MacBook Air: $789.99 110 off original MSRP - 11″ 256GB... Read more
Apple refurbished Time Capsules available for...
The Apple Store has certified refurbished Time Capsules available for $100 off MSRP. Apple’s one-year warranty is included with each Time Capsule, and shipping is free: - 2TB Time Capsule: $199, $100... Read more

Jobs Board

*Apple* Solutions Consultant - Retail Sales...
**Job Summary** As an Apple Solutions Consultant (ASC) you are the link between our customers and our products. Your role is to drive the Apple business in a retail 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) - D...
Job Description: Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, Read more
*Apple* Systems Engineer - Pre Sales, Educat...
…is responsible for proactively providing technical expertise to drive sales of Apple solutions into assigned accounts. The SE architects, validates, and assists in Read more
Sr. Technical Services Consultant, *Apple*...
**Job Summary** Apple Professional Services (APS) has an opening for a senior technical position that contributes to Apple 's efforts for strategic and transactional Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.