Tutorial: Turn Your Mac Into an AirPort Base Station

Posted by Dan Booring on 07/22/07 in Tutorial, Featured, Hardware, Tips & Tricks, Internet, Home & Personal, Apple

AirPort Symbol You may not know this, but if you have more than one Mac and you’d like to share your Internet connection between them, there’s no need to buy an AirPort base station. Mac OS X comes with the software you need to turn almost any Mac into a base station all by itself.

So, if you have, say, an iMac in your home office and two MacBooks floating around your home, you can share a single cable modem connection between all three computers without purchasing any more equipment.

The idea is pretty simple: the first thing you need to do is get one Mac connected to the Internet. The good news is that, if you have a working Internet connection, Mac OS X is smart enough to do that for you; just plug an Ethernet cable between your broadband modem and your Mac. That is the only wired connection you’re going to need to make.

The second step is to set that Mac up to share its Internet connection with others, and to configure all of the related preferences. Finally, you connect your mobile machines to the network you created in step two, and you’re done.

Setup Diagram

The only requirements are that the “base station Mac” has to have both an Ethernet port (they all do) and an AirPort card (all of the current notebooks, iMacs and Mac minis do, it’s an option on the Mac Pro). Also, you need to be running Mac OS X. I am not sure which versions are required, but I know both Tiger and Panther can do this. (If anyone tries with a version earlier than Panther, please let us know in the comments how it goes.)

This works best if your Base Station Mac is a desktop machine because it’s got to be up and running whenever the other machines want to connect to the Internet. So if you use a notebook, your network will go down whenever you put it to sleep or shut it down.

On your Base Station Mac, open System Preferences and choose the Sharing Pane. This is where you go to turn on things like Printer Sharing and File Sharing… and it’s also where you’ll find the setup options for Internet Sharing, the magic mojo that will make your network run.

Sharing in System Preferences Once the Sharing Pane opens, click on the Internet tab at the right end of the bar to bring up the relevant options. Now, this screen is so simple that most of this explanation is totally unnecessary. Nevertheless, here it is: before the big Start button becomes clickable, you’re going to need to choose which “port” you want to use to share your internet connection.

Sharing System Preference

Keep it simple and check AirPort. All that means is that, when the Internet comes in to your Base Station Mac’s Ethernet port, you’re going to share it out of the AirPort port. The AirPort Options button is where you give your network a name and set up its password. Do this, then click the big, ol’ Start button. Once you’ve done that, you’re home free.

Now look up at your Menu Bar where your AirPort icon usually sits… it’s different! The icon now shows that you’re running an outbound network and all your other Macs should see it automatically. Just turn on one of the machines that you want connected to your new network and hit the AirPort Menu. Type in the appropriate password, and off you go. Simple, no?

Except for the fact that your Base Station Mac needs to be on all the time, there is no real downside to this technique. Your ISP may limit how many computers you can connect to a single modem but, barring problems with that, you should have no trouble at all. Experienced readers may want to check out the Printer Sharing settings in the Services section of the Sharing Pane to setup a single USB printer on your Base Station Mac, which can be accessed from all your wireless machines.

Let us know in the comments how it goes!

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35 Comment(s)

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kenny said on

July 22nd, 2007 at 9:00 am

I have done this setup for a few friends before, and it works really well. However, in all cases the “routing” computer have been the newest. I did this in my own home yesterday, hawing my mac mini share it’s connection via airport to my macbook. And it worked terrible. I had to give it up and go back to my airport express as routing device. I’m not sure what the problem might have been though. Maybe it has something to do with the fact that my macbook is 802.11n enabled and my mac mini isn’t. Sounds strange though.. On the other hand, I’ve had really weird problems with my mac mini ever since the 10.4.10 update. Even on freshly installed systems.

I did this setup from a newly installed OSX (Clean install from DVD, update to 10.4.10 and then turned on the sharing), still something weird happens with my update. Several times have I had to reinstall the system on my mini after the 10.4.10 update, even if nothing have been installed on the system prior to the update.

Generally my expirience is that this works very well though. Expecially if you have a high speed connection. The reason I wanted this setup is because the fact that the airport extreme backplane can’t handle the load of a 100mbit connection, but the mac mini can. Unfortunately it didn’t work that well in my case.

kenny said on

July 22nd, 2007 at 9:01 am

opps, i mean “airport express” in the last paragraph there.. I don’t know if the new extreme can handle it.

Will said on

July 22nd, 2007 at 9:50 am

Awesome article!

I will definitely try this out when we get the next iMac that comes out. I don’t know why more people don’t do this. It’d save so much money on a router.

RodP said on

July 22nd, 2007 at 1:04 pm

Will, one possible reason may be wireless range. If the desktop Mac is stuffed away in one corner of the house, it may not be as useful as a base station. A centrally-located Airport unit would be preferable in that case.

Julian said on

July 22nd, 2007 at 3:37 pm

I think i saw this on CNET but this has mor3 d3tails so thx onthat and atleast it wasnt an “ADVERTISEMENT” like da last article on some Logitech keyboard.

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Marvin Sum said on

July 22nd, 2007 at 5:06 pm

An old Mac Mini would be just the right size for this sort of thing. Unfortunately, I don’t think it’s got 802.11n?

Julie said on

July 23rd, 2007 at 2:02 am

Have tried this several times unsuccessfully with our dual processor desktop iMac (new this year) hooked up to cable internet via ethernet. Was able to establish a network with our brand new laptop, but not access internet. Could be a Time Warner cable issue?

Anyone out there know of a workaround? We really do not want to pay TW extra just to have internet access for the laptop occassionally.

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kenny said on

July 23rd, 2007 at 3:33 am

Julie: you have to make sure that the firewall on the routing computer have the ports open that you need on your laptop. like port 80 for web browsing.

jan said on

July 23rd, 2007 at 6:53 am

hi! i do this all the time with my mom’s core2duo imac and my macbook…it does in fact work, but although we have 1.6 megabyte/s broadband connection, the aiport connection is quite slow… you are better off investing 179 bucks into the airport base station or about 40 bucks in an average wifi router..

grzybu said on

July 23rd, 2007 at 7:21 am

I’ve been sharing my friend in our flat. I’ve got MBP CD and he uses IBM Laptop. The only thing that I don’t like is the fact that the connection is unsecured. There’s no way to use secure connection when sharing internet to Windows machine

tim said on

July 23rd, 2007 at 7:34 am

Jan -1.6 mb/sec broadband isn’t that fast. I have 10 mb/sec here in Madison. Now if you had that and it was still slow, then I’d say something is configured wrong. But 1.6 mb/s would probably be expected to be not that great.

jan said on

July 23rd, 2007 at 7:46 am

tim: i’m not talking about 1.6 mega BIT, i’m talking about 1.6 megaBYTES, which puts me in the position of downloading a movie (ca. 700mb) in less than 15 minutes…quite fast, eh? ..well not when i use my mom’s imac as an aiport base station -.-

Joao Barros said on

July 23rd, 2007 at 8:15 am

I’m using this method to share my 3G to a friend that’s sharing the apartment while we’re on vacation and it’s working well.
For those who say this saves money on a router I have this for ya:
- The antennas on a Mac are not the antennas you get on a AP/wireless router, whatever.
- The highest security level this method permits is WEP. WEP is easily cracked, and if you’re on a crowded area, most probably someone is snooping on your traffic. WPA2 is the only secure option right now and it’s not supported.

As I said on top, I’m on vacation, and for a temporary need this setup works, for an everyday setup, for the reasons stated above security being the top one, this isn’t recommended.

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Jonathan Wise said on

July 23rd, 2007 at 10:28 am

Another consideration about this set-up is that directly exposes one of your computers to the Internet.
Most routers act as hardware firewalls, allowing you to open only specific ports to a specific machine. When you connect a computer directly to the Internet, all ports are open to the wild, and the potential for malicious activity directly against your network increases.
Of course Macs are more secure than most computers, but this is still a pretty dangerous set-up. A router costs less than $40 this day — with wireless, and provides a layer of hardware protection. Its well worth the money.

Joao Barros said on

July 23rd, 2007 at 10:44 am

@Jonathan Wise:
Actually when you turn a Windows, Linux or FreeBSD machine (haven’t tested with a Mac but I suppose it works the same way) into a router(NAT), if you need any port open(listening) on that particular machine you have to specify it. It’s the same method you would use to open ports to specific machines, but for the local machine.
On a NAT setup, usually connections are opened from the inside and the router only let’s traffic in on the same connection that was created from the inside(TCP) or related to that communication (UDP).
If you use a firewall just to close ports, NAT will do the same as incoming initiated traffic will be disgarded, so contrary to what you say, NAT is a secure setup.

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Julie said on

July 23rd, 2007 at 11:37 am

HI all. I appreciate all the feedback. I’m not sure how to open one specific port on the desktop, but I do have everything checkedc off in the firewall to allow internet and printer sharing.

The laptop can hook up to the desktop network, but I am unable to get remote printer access to work (our printer does not show up in a a scan of devices) nor the internet connection.

Now, this laptop is provided by hubby’s work–is it possible that they have disabled something? I know in the past with an older laptop they had frozen his hard drive to not allow any downloading and saving of anything (he had to be connected remotely to their network and then could save onto his drive on the company network.)

This is frutrating, but I am determined to ge tit to work if at all possible. We were consdiering a router, but givein that he really does not require access all that much from home, it seem slike an unnecessary expense right now.

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alansky said on

July 23rd, 2007 at 7:33 pm

Connecting a computer directly to the internet may expose it to the risk of attack, but most people who don’t have a home network DO connect directly to the internet. Most people don’t buy routers unless they’re creating a network. Driving a car is also dangerous. Come to think of it, so is walking on the street. The safest thing is to stay home, disconnect your cable modem, turn off the lights and pull down the shades.

John E. said on

July 25th, 2007 at 9:45 pm

I tried this setup with a macmini I just bought and it works great! I had to adjust the advanced firewall settings in preferences to allow UDP packets.

The only problem I have with this setup is that my macmini has to be on all the time. If I let it go to sleep and then wake it up I have to reset the internet sharing in the sharing preferences otherwise my macbook pro cannot connect to the wireless signal.

Does anyone know of any software that will allow you to put my macmini to sleep and wake it when my macbook needs wireless access?

Please let me know…I have been searching the web, but have not found anything suitable yet.

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L'affreux said on

July 31st, 2007 at 2:11 pm

I use this tip since a long time. I have an eMac behind a router and a modem, it shares my internet connection to my brother’s laptop and mine when needed.

It works really great but there is one thing I find boring is that when you want to activate it you always have to go in the preference panes. It would be nice to have a widget to start the sharing or even in the airport menu (in the menu bar).
Anyone heard about an app which can do it ?

Thanks

ron said on

September 9th, 2007 at 9:04 pm

I’ve tried this using my new imac as the base station, and my rev b imac as the computer connecting to it.

worked without a password, but I wasn’t comfortable with that, so I added one. now it doesn’t work at all, even when I try to un-password it. it’s strange, the old mac finds the new mac, connects, but no file sharing or internet. the old mac is using a belkin usb antenna that’s not technically designed for it, but like I said, it worked for a little while…

are there settings in the internet connect panels or in the networking control panel that I need to re-set on the old mac?

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JULIE said on

September 9th, 2007 at 10:46 pm

UPDATE

Turns out that our problem was simple to resolve–we just had to turn off the cable modem for a bit to let it essentially resset, then turn it back on AFETR we had the two computers communicating via Airport. Sometimes the Internet sharing would not go on the first time it was checke doff…not sure why not, but once we go back in it works every time.

I’ve also found that the speed in browsing increases dramatically when we turn on personl web sharing in the Service pane of hte Sharing preferences folder. All in all I’m quite happy . And, as an aside, TimeWarner does not care how many computers you have hooked up in your home network.

Thanks everyone!

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JULIE said on

September 9th, 2007 at 10:53 pm

ANOTHER NOTE

Contrary to comments I’ve read, the iMac Airport sends out an amazingly strong wireless signal. We’ve been able to be clear across the house with 2 rooms (one with a lot of heavy wooden furniture in it to potentially provide a lot of interference), a hallway and a closet between the base computer and the laptop and the connection stays strong.

HOWEVER, one caveat is that it does seem to help immensely to be close by when you first establish the connection.

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jeff said on

September 16th, 2007 at 6:50 pm

this worked for me using a mac mini to an iPhone! I had to turn off my firewall, though. Anyone know if that absolutely a must?

cuvtixo said on

September 17th, 2007 at 10:42 pm

You can check Personal Web Sharing in Firewall tab in Sharing control panel (services-firewall-internet) and only share http and keep firewall on other services and ports. Note: dedicated “wireless routers” use a lot less electricity as well as including a built-in firewall offering more protection. They are a good idea. IPNetRouterX for $100 (free trial download) is a decent alternative: if you’re willing to take the time (and spend the bucks)to learn about networking. If you’re in a place where neighbors or wardrivers might do more than innocent surfing- wireless internet sharing is not a good idea- you best bet is to buy some long pieces of ethernet wiring and keep that wire! Its like wearing a raincoat- or ya know… I mostly trust my neighbors (but not their teenagers!) anyways better safe than sorry.

Isaac Salam said on

September 27th, 2007 at 1:30 pm

Like some have mentioned above, I notice that I have to reset the Internet Sharing by turning it off and then *start* again. However, I never turn off my MacMini…I’ve noticed having to do this when my MacBook has been shut or in sleep for a while. Does anyone have any ideas as how to solve this problem, or why this is happening?

Secondly, I have decided to plump down money for a QuickerTek aCard for the Mini, which makes it into a true 5ghz 802.11 a/b/g/n machine. Why not just get an Airport Extreme? I have a 750gb Maxtor connected to my mini by Firewire, and the Extreme doesn’t have a Firewire port (just USB, which might be fine for some). I use this to wirelessly backup using SuperDuper to a disk image (which works faster than you’d think with a fast wireless connection). The QuickerTek card comes with an antenna to further the distance that it reaches. Hasn’t arrived yet, but I’ll post back if anyone’s interested when it does.

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Shaun said on

October 21st, 2007 at 2:16 pm

This worked beautifully first time on an old iMac red 333mhz running 10.4.10. Thanks for the tip.

Is it possible to configure as a repeater to an existing wireless network?

Shaun

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gf said on

October 30th, 2007 at 3:21 pm

This no longer works in Leopard 10.5 It requires you to create a network

Ryan said on

November 16th, 2007 at 3:17 pm

For some reason, this same setup works incredibly slow for me. Browsing on the client computer is significantly slower than when using the host PC. Oddly enough, the same feature works much better in Windows… I guess this is the ONLY thing that is better in Windows than OS X.

If anyone has any tips, I’d love to hear them. I also wonder if I should downgrade to 10.4.9… I’m currently running 10.4.11.

TheCiscoKid {at} gmail {dot} com

-Ryan

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Jim Small said on

December 25th, 2007 at 3:10 pm

Used this set-up to connect G4 PowerBook w/OS 10.4.11 (Airport Extreme) to a G5 MacPro w OS 10.5.1 (Airport Extreme). Internet and Web sharing were on. Worked great and browsing on the G4 was not noticeably slow. Also connected my daughter’s new iTouch using the same set-up. Worked great.
The G4 is usually connected via an Ethernet router. Now I’ll use the Airport set-up if I want to surf from elsewhere in the house.
Thanks for the tip!

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Christy Petty said on

February 20th, 2008 at 6:12 pm

THANKS- This worked great then we lost it..- We had issues with our itouch just after upgrading and then using another network out of town. So decided to use up our tech help before it wore out– could not find this site right away–
Apple says this can not be done–they have become so PC –
I finally found you again (filed wrong in bookmarks)
Thanks for thinking like a Mac…

JULIE said on

February 26th, 2008 at 2:19 pm

LEOPARD UPDATE

This does in fact work with the new OSX 10.5. Setting up a home network is so simple and provides a little bit of added password protection that you should go ahead and do it even if you don’t have to.

Still loving it.

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JSA said on

March 7th, 2008 at 1:50 am

Hi!

Would you know if this also works with iPod Touch (i.e., if I already have set up my iMac 10.5 as my base station, can I connect my iPod Touch to it and use Safari or YouTube on my iPod Touch?)

Hope you can help me on this. Thanks!

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Weja said on

March 14th, 2008 at 4:14 pm

———Cannot Turn on Airport ————-
I am trying to connect to a wireless router and i dont understand what I need to do to allow the router to recognize my laptop (Mac Powerbook G4, version 10.3.9) .. any hints?!
A friend asked me to check if I have an Airport card, and I guess I do have an AirPort card installed , because before I had no problem in connecting wirelessly at the office and in my friend’s house?!! Lately I noticed that I don’t see the AirPort icon in the toolbar and when I went back to the Network Port Configurations, the airport checkbox wasnt selected and the weird thing is that I cant even select it? I have no idea why?! I can select and unselect the rest of my network ports (internal modem, bluetooth, etc ) but not the Airport icon!!!! I’m so confused, it was working fine before !? Why I cant select the checkbox?! HELP ME

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Sandra said on

March 21st, 2008 at 6:05 pm

Hi, I had pretty much done what you described and can surf the internet, but cannot download mail. Also,I cannot access any webmail. It just won’t load the pages, while other pages load fine. I can’t pull up any cpanel login in pages on the web either. Thanks for any help. Sandra

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Grant Brown said on

March 24th, 2008 at 6:35 am

PROBLEM TOO
the same thing happened to me as to kenny. i set it up, but the performance is terrible and the device using my mac mini’s connection seems to only have the internet intermittently. doesn’t work with mac book, ps3, or iphone. going back to dlink.

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