IPNetRouter Guide to AirPort
- Introduction to AirPort and IPNetRouter
- Determining the Best Mac-based Wireless
- Apple's Hardware Base Station Solution
- Base Station versus Computer-to-Computer
- Improving IPNetRouter and AirPort
- Using IPNetRouter's FBA with AirportAdditional
Important AirPort and Wireless Info
Introduction to AirPort and IPNetRouter
IPNetRouter can be used to expand the capabilities of a wireless
network using a Mac as an Internet router or NAT gateway beyond
the Airport hardware and software provided by Apple. Once Airport
is verified to be working without IPNetRouter, you can just treat
the Airport card as if it was an Ethernet interface for purposes
of IP configuration
for Internet sharing or routing for purpose of IPNetRouter configuration.
AirPort terminology. Apple's hardware and software base stations
are sometimes referred to as "Access Points". For purposes
of brevity, the abbreviation "HBS" is used for the hardware
base station (aka hardware access point). Pay careful attention
to the use of "Software Base Station" software, "Base
Station mode", the AirPort card itself, and the HBS in the
rest of this guide. The differences between the various components
of wireless networking can be important when you attempt to configure
IPNetRouter with AirPort hardware.
Determining the Best Mac-based Wireless
When you install Apple's software that comes with an Airport card,
it includes a limited version of IPNetRouter that Apple licensed
from us. The main reason you might need IPNetRouter for your wireless
network is that Apple's own Base Station solutions are not adequate
on their own. If all you want to do is to share a single Internet
IP address among several wireless Macs then Apple's AirPort solutions
may be all you need. Some of the things to consider are the number
of subnets you will require, Appletalk capabilities for printing
on your network, future capabilities, what interface you wish to
perform NAT through, and many others.
IPNetRouter and AirPort Feature Table
Base Station Update (HBS)
Base Station release 1.3
than one subnet on a single interface
Mac be on for routing/sharing?
over Ethernet (PPPoE) DSL Support
||1.3 or later
with the 2.79 firmware update
more than one NAT Interface at a time?
including the AirPort interface
||Not the AirPort
interface and not more than one
to other than Ethernet and AirPort
Mac with AirPort card
servering on more than one interface
AirPort card ($99)
provide technical support
Here are some specific reasons IPNetRouter might be a better wireless
solution then Apple's software:
- You wish to use a single or dual ethernet LAN with your AirPort
gateway in addition to having a wireless component. AirPort 1.3
supports seperate wireless and Ethernet IP subnets simultaneously
if you have a PPP dialup. Apple's software is limited in the address
range supported and cannot use DHCP server services on the Ethernet
portion of the LAN. IPNetRouter does not have these limitation
and can be deployed as a full router between any ethernet or other
physical interfaces that have the appropriate drivers. For example,
TokenRing, Firewire, MacIP, etc.
- Its cheaper overall for initial hardware cost then using a HBS.
$99/AirPort card plus $89 for an IPNetRouter license. Since IPNetRouter
permits two, three or more interfaces, you can use it to route/share
between all IP multihoming compatible data link providers on a
particular Mac. The HBS is limited to just one ethernet and one
wireless LAN component.
- IPNetRouter supports having the AirPort wireless interface be
the one through which NAT takes place. Apple's user interfaces
do not support IP Masquerading on the wireless interface.
- You need other complex IP routing, filtering, and port mapping
capabilities using the wireless Interface. As an example, IPNetRouter
supports multiple sublans on single physical interfaces, including
AirPort. Thus, using our software, you could have two seperate
sublans sharing the same AirPort wireless link simultaneously.
- Computer-to-Computer mode can be used with IPNetRouter. Apple's
software requires Base Station mode to do Internet sharing. This
has possible performance benefits.
- You have a "PPPoE" style connection over a DSL modem.
If you are not sure what type of DSL connection you have or will
be getting, contact your local DSL provider to determine whether
they require "PPP over Ethernet" to connect to their
highspeed services. Many DSL providers require this for their
cheapest high-speed accounts. Apple's AirPort 1.3 or later software
supports some PPPoE implementations. Contact Apple for more info
about PPPoE AirPort compatibility.
- We can provide support for IPNetRouter configuration in conjunction
with AirPort or other wireless solutions.
Apple's Hardware Base Station Solution
The AirPort Hardware Base Station is running a version of KarlBridge,
which was developed by Doug Karl at Ohio State <http://www.karlnet.com/news/199912/199912-Airport.html>.
Our routing configurator software is not part of this implementation.
Apple's AirPort HBS is, however, a perfectly good wireless networking
solution in many situations that might include IPNetRouter. Here
are some points to consider about the HBS.
- Transparent Bridging Mode(TBM) support. Apple's HBS can do Appletalk
bridging because it does ethernet to wireless network bridging
of all ethernet packets. (Although Appletalk and IP appear to
be 100% supported in this mode, there may be other limitations
with TBM--contact Apple to determine what is or is not supported
by this mode.) IPNetRouter and Apple Software Base Station do
not currently support Appletalk bridging/routing, although do
support Appletalk as outlined in the IPNR FAQ. The HBS is better
if you want to use Appletalk based printers and other Appletalk
services across your wireless network.
- Unlike the SBS and IPNR solutions, you don't interrupt routing
to other wireless Macs if your gateway Mac is turned off. The
HBS takes up very little power and, if power is maintained, should
not have the potential for network disruption that restarting
a Mac gateway might. However, if you are planning on keeping at
least one machine continuously connected to the Interenet anyway
- Its $299. IPNR plus an AirPort card are less than $200.
- Fortunately or unfortunately, purchasing the HBS means you are
purchasing hardware that performs only one function. IPNetRouter
can be used to route over all sorts of different transports, not
just 10mb Ethernet and AirPort wireless. You are limited to that
functionality for the life of the HBS.
- IPNetRouter and the SBS-FBA support Trace Route (NAT with ICMP
translation), can work with PPTP, and have various other implementation
differences. As outlined elsewhere in this chapter, they have
the potential to offer higher performance and more flexibility
then the HBS.
Deciding on wireless networking solutions can be difficult sometimes.
We are happy to field any questions on whether IPNetRouter may or
may not be appropriate for your network. If you submit an IPNetRouter
related AirPort question using our browser
based support form we will be happy to respond. We should mention
though that we are not the support solution for Apple's own AirPort
software and hardware. If you are looking for AirPort support that
does not involve the configuration of our IPNetRouter software,
consult the AirPort documentation or contact Apple.
Base Station versus Computer-to-Computer
[Peter] Apple's Hardware Access Point (aka HBS) operates in Base
Station mode only, whereas the AirPort software in combination with
IPNetRouter can set the radio to either Base Station, or Computer-to-Computer
mode (802.11 "ad-hoc" mode).
Base Station mode is similar to a cellular network and provides
relaying and power saving features. The Base Station can buffer
traffic for low power clients allowing them to periodically turn
on their radio and ask the base station for any traffic that may
be waiting. By switching on the radio only long enough to receive
any waiting traffic, clients can save precious battery power by
not operating the radio all the time.
In Computer-to-Computer (ad-hoc) mode, the radio listens for incoming
traffic all the time. Computer-to-Computer mode is intended for
setting up ad-hoc limited range LANs when no base station (or cellular
network of base stations) is available. As a side effect, it may
offer better network performance, but consumes more power. [Tim[
We recommend you use Computer-to-Computer mode with IPNetRouter
whenever possible, thus avoiding arbitrary interruptions to your
wireless network caused by the waking up and going to sleep of AirPort
cards. Further, this reduces the chance of generating base station
mode configuration files that give IPNetRouter conflicting instructions.
By setting the AirPort Software to use Computer-to-Computer mode
along with IPNetRouter, it is possible to connect remote Ethernet
LANs via wireless networking. AirPort wireless is just another data
link provider logically equivalent to Ethernet.
Since Apple has not published the commands to switch the radio
between Base Station and Computer-to-Computer mode, the only way
to select Base Station mode is to use the AirPort Setup Utility
(and then optionally modify the configuration or switch over to
running the commercial version of IPNetRouter).
Improving IPNetRouter and AirPort
Apple's Software Base Station (SBS) uses a licensed version of
IPNetRouter supplied as a Faceless Background Application (FBA).
This is important to remember when configuring IPNetRouter because
this is mainly where potential conflicts arise. The following instructions
apply to IPNetRouter 1.4.7 or later
and AirPort 1.2 or later. We strongly recommend that you install/update
to AirPort 1.2 or later to
minimize conflicts between AirPort and IPNetRouter.
Installing the AirPort software may remove IPNetRouter's OTModl$Proxy
extension and replace it with a possibly older version named "AirPort
AP Support". Also note that Apple usually updates Open Transport
itself with AirPort updates. Be sure to reinstall IPNetRouter, IPNetMonitor,
IPNetsentry and/or any other third party networking software (like
PPPoE client software) after installing a software update of any
Apple AirPort software.
[Tim] In order to futher minimize any conflicts between the AirPort
and IPNR I recommend that you use IPNetRouter only in Computer-to-Computer
mode unless you have a good grasp of how AirPort works. It avoids
the complications that can occur if your AirPort cards fall asleep
or you accidently attempt to enable software base station mode with
our software installed. I use this method on my own home office
network quite effectively. Before I did this I had all sorts of
Before installing IPNetRouter or while IPNetRouter is not running
on the gateway Mac:
- Set Computer to Computer mode on the gateway Mac for
- Verify that Appletalk works between the gateway and another
wireless Mac using Filesharing. If it doesn't, don't proceed further
until you can get this to work without IPNetRouter before proceeding.
- Open the AirPort Apple menu item
- Using the Software base station button, verify that your
gateway machine is not in software base station mode. If it is
running, turn this off and then close the "AirPort"
- Next, open the Extensions Manager control panel.
- Disable the "AirPort AP" and "AirPort
AP Support" files. (These are the equivalent of the IPNetRouter
FBA and "OTmodl$proxy" extensions. Disabling these extensions
does not prevent AirPort from working but will prevent potential
conflicts with certain files created when Software Base Station
mode is configured on the IPNetRouter gateway machine; the files
involved are explained elsewhere in the AirPort section of the
- If the "AirPort AP Configuration" file is present
in your system's Preferences folder, remove it (do not delete
it if you might want to switch back to a software base station
configuration you've used successfully in the past--always a good
- Reboot the gateway machine.
- Begin configuring IPNetRouter as you normally would for
an Ethernet interface. See elsewhere in the IPNetRouter Guide
for typical ethernet configurations.
Using IPNetRouter's FBA with AirPort
([Peter] The AirPort software Internet access point is a limited
version of Sustainable Softworks Faceless Background App (FBA) and
is configured using the AirPort Setup Utility. Turning on the Software
Base Station feature writes out an IPNetRouter configuration file
named "AirPort AP Configuration" in your Preferences Folder,
and then sends an Apple Event to launch AirPort AP. Any changes
you make to the Software Base Station writes out a new "AirPort
AP Configuration" file. To use IPNetRouter to extend your AirPort
configuration, you have two choices:
- Quit the AirPort AP FBA and launch the UI version of IPNetRouter
to modify your IP network configuration directly.
- Modify AirPort AP to use a different configuration file that
you specify (STR# resource 131 Option Settings, "ConfigFileName=AirPort
AP Configuration"). [Note this technique is for registered
IPNetRouter users who wish to integrate their use of IPNR with
AirPort. Proceed at your own risk since the AirPort Setup Utility
could produce unexpected results.]
- Use our FBA instead of Apple's. In this case, disable the AirPort
AP files in your system's Extensions and Preferences folder.
To verify whether your AirPort AP configuration succeeded, you
can examine the "AirPort AP.log" file in your Preferences
Additional Important AirPort and Wireless Info
Apple has updated AirPort Software and hardware firmware (for the
HBS) several times since they were first released in 1999. Apple
has also issued numerous technotes on some of the limitations and
other idiosycracies of AirPort hardware and software performance
and configuration since its introduction. To see all the technotes
with regard to AirPort, use Apple's
search engine. See also the IPNetRouter Troubleshooting
section of our web site.
If you are looking for information about wireless LAN solutions
other than Airport, a good place to start is our web based nettalk
archives search engine.
Disclaimer: The information above is from
existing published sources or otherwise readily available.