iPhones, iPods, & iPads forum

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Connecting an iPhone to an iMac without a WiFi-router

by k-tut / November 10, 2009 2:17 AM PST

My iMac is on a LAN using wired Ethernet (not WiFi).

I have set the iMac to share the internet with the iPhone using the iMac's built-in Airport, and the iPhone seems to get a signal from the iMac, but I am not able to visit any sites on the net no matter what I do.

Am I wrong in assuming that I can surf the net thru my iMac? Or do I have to get a WiFi-router?
The reason I am avoiding a WiFi-router is that all the ones I have seen would limit the speed of my connection (100 Mb/s).

(I have not been able to get the iPhone and iMac to use Bluetooth either though they are paired.)

Thanks for any suggestions.

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That should work, but,
by mrmacfixit Forum moderator / November 10, 2009 7:33 AM PST

I'm not sure I understand your reasoning behind not getting a wireless router.

Just how would having a wireless router slow down your connection?
You iMac would still be wired directly to the router, as it is not, with the iPhone using the WiFi portion of the router at "G" speed.

Does the iPhone get a valid IP address from your iMac?


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I have avoided wifi up to now...
by k-tut / November 12, 2009 2:21 AM PST
In reply to: That should work, but,

Any router will reduce the speed of the connection compaired not having one. When the speeds are almost 100 Mb/s most routers only let through abot 15 - 20 Mb/s. Maybe someone knows of a router that doesn't, I don't. Besides, I have had no use for any WiFi until now that I got the iPhone 3GS.

Well, on my iMac I created an Airport network (DHCP) Self-Assigned IP: and the Subnet mask is

On my iPhone I have connected to the network with the name I created on the iMac, and it is assigned an IP: and subnet mask, Router: and DNS:I entered the same one as I use on the iMac (it gave me the same server as the router, but that can't be correct? So I changed it)

So, why can't I get on the web? Google Earth Found my location! But Safari can't find any server - "The server stopped responding". (The iPhone is less than 3 feet from the iMac. And, I am running the latest software all around.)

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a little clarification
by d_adams / November 12, 2009 2:41 AM PST

First, this is not possible. It is possible to use your iPhone's 3G or EDGE connection on your Mac via Bluetooth or the USB cable, but it is not possible to do the reverse.

Secondly, You seem to be a tiny bit confused about wifi, which is perfectly understandable. A wifi router doesn't limit the speed of your connection at all, unless you were to have an exceptionally fast connection, because, right now, your connection speed is most likely under 10MB/s. I know it SAYS it's 100MB/s, but that is just the speed of your home network (the speed at which data may pass between your computer and your current router, switch, hub or whatever you've got). The external speed (the speed at which data may pass between a server somewhere and your current router; in other words your "internet speed") is the limiting factor. Unless you've got a fibre optic cable going into your house, then your connection is going to be considerably less than 100MB/s. My own connection speed is 3.5-4.5MB/s, and it's a broadband internet connection; one of the fastest available in my area. If you'd like to find your own internet speed, go to this site http://www.speedtest.net/ . It will tell you the 'Ping' (how long it takes for a message to make a round trip from your computer to a server somewhere), your upload speed (the speed at which you may send data from your computer to a server), and your download speed (the speed at which you can receive data from a server). For most intents and purposes, the download speed is the only one that matters much.

Anyway, back to wifi routers. All a wifi router does, is "split" your internet connection, so to speak, into two streams; wireless for your iPhone and wired for your iMac. You will still be able to get the same speed, because it only splits the connection it's self; not the speed. In any case, you then have two internet connections. There is one more added complication. Not all wireless connections are the same speed. Most routers broadcast at two or more frequencies. The most common frequency, and the one used by ALL routers these days, is 802.11G, or just Wireless G for short. This one has a maximum speed of 54MB/s, which (although only half the speed of your ethernet connection) is fast enough to not limit you. Your iPhone can connect to a wireless g connection. So, this is the one you'll need. Some new devices and computers can connect to a Wireless N connection. It supports data transfer speeds of up to 300MB/s over the wireless connection. I've got both kinds of routers, and I don't really notice the difference.

So, just get a wireless G router, and you'll be set!

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Clarify please,
by mrmacfixit Forum moderator / November 12, 2009 4:17 AM PST
In reply to: a little clarification

An iMac, directly connected to a router, shares it's internet connection via its built in Airport.
Once configured, any other wireless device can join this network and surf the internet.

I don't see anything in the OP's posts, or mine, that was attempting to do anything other than the above.

The iPhone should connect to the wireless network of the iMac that is sharing the internet connection.

Why would the iPhone not connect to the internet in this scenario? Other wireless computers would.


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Very fast connection
by k-tut / November 12, 2009 4:41 PM PST
In reply to: a little clarification

Thanks d_adams for responding. In most cases what you state about routers is correct, but not in my case. My ISP delivers as near to 100 Mb/s as it gets (I have used even faster lines before). Without a router I reach speeds around 80 Mb/s (up and down), but with a Linksys RVS4000 it drops to 16 down and 6 up, so I only use it when I need to connect another computer. The Linksys is supposed to handle the load, but does not.

I will get a WiFi router if that is what it takes, but I have always been under the impression that the iMac on its own can act as an Airport hub when conncting to another computer (here the iPhone) and was astonished it did not.

While writing this I was able to find a neighbour who has an open network (very rare these days), and was able to get on the net using his network, so my iPhone is OK thank God.

Now, why is my iMac not sharing the net when in fact it is connected to the iPhone? The phone find the network in its list. Weird.

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Solved the problem
by k-tut / November 12, 2009 9:18 PM PST
In reply to: Very fast connection

I had forgotten that my firewall (Intigo NetBarrier) was set to Client. I have changed that to Client and local server, and it now works. At last! I was sure it was something simple.

Now if I can get Bluetooth to connect (it is paired) all will be fine. (I don't know what I might need it for, but since it is there...)

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That explains that problem,
by mrmacfixit Forum moderator / November 12, 2009 10:48 PM PST
In reply to: Solved the problem

and proves my answer.

The Bluetooth function on the iPhone does not do anything much when connected to your Mac but is handy for things like BT headsets, connecting to an in-car navigation device or a BT capable input on your vehicle radio.


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by k-tut / November 12, 2009 11:47 PM PST

I would just like to thank both mrmacfixit and d_adams for taking the time to get me on the right track.

It is nice to have helpful people to turn to when one is stumped.

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(NT) you're welcome
by mrmacfixit Forum moderator / November 13, 2009 4:15 AM PST
In reply to: Thanks
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