Free ethernet loopback software for mac

Apple Ethernet Update 2.0 is a reliable and useful live update module which improves AppleShare connections in high-traffic network environments.

The Apple Ethernet Update 2.0 consists of version 2.4.3 of the Apple Ethernet extension. When you use certain Mac OS 9 applications while connected to AppleShare volumes, disconnections can occur. You may see "TickleTimeout" disconnect messages in the Mac OS X Server 10 Apple File Service access log. The Apple Ethernet Extension 2.4.3 prevents these disconnections from occurring.

Although USB to Ethernet adaptors are cheap and plentiful, Mac OS X drivers are not.
USB-to-Ethernet offers you USB to Ethernet Adaptor Drivers.
There are two basic catagories of USB-To-Ethernet adaptors:
- USB 1.1 devices that use a Pegasus driver.
- USB 2.0 devices that use a AX8817x driver (or its successor, the AX88772).
Each disk image includes an installer for Panther or Tiger, and a "src" folder containing the corresponding xCode projects.
Installation
Download and mount the appropriate driver disk image listed above, run the corresponding installer for Panther or Tiger, and then restart your system as suggested. The Installer will ask you to authenticate so it can place the corresponding driver in "/System/Library/Extensions/" with the correct file permisions to load as a kernel extension.
Next, plug-in your Ethernet adaptor with a live Ethernet cable attached. When you open the Network Preferences panel, it should inform you that a new port has appeared and ask if you want to enable it. Enable the new port and apply your network settings. Thats it.
Each driver is pre-configured to recognize a handfull of common devices. If your device does not appear to be recognized by the driver, you might have to add it to the Info.plist file, which is located inside the USBPegasusEthernet.kext or USBAx8817x.kext directory. You can use the System Profiler or USBProber tool to find the corresponding Product ID and Vendor ID.
To uninstall the driver, make sure any USB adaptors are disconnected, and then drag the corresponding driver in /System/Library/Extensions/ USBPegaususEthernet.kext or USBAx8817x.kext to the trash. You may need to authenticate that you have administrator privileges.
USB 1.1 Performance
The Pegasus chipset provides a USB 1.1 compatible implementation which could be a concern for some users. USB 1.1 runs at 1.5 Mbps (low speed) or 12 Mbps (full speed). For best performance, its important to isolate any low speed devices on a separate bus. Mice and keyboards often run at low speed.
Using the Link Rate tool in IPNetMonitorX, I measured the link rate to another device on my LAN as 6 Mbps. The built-in Ethernet on my 12" PBG4 reported 44 Mpbs. When I measured the link rate to the next hop router through my cable modem, it reported 1 mbps. It didnt make any difference whether I used Ethernet built-in or the USB-To-Ethernet adaptor. Finally, I downloaded a 2.2 MB file to compare the throughput using the Monitor tool.
Both downloads took 5 seconds, but Ethernet built-in reached a peak rate of 589 KBps versus 579 kBps. Repeating the experiment several times produced similar results. Ethernet built-in might be 1-2% faster, but performance was clearly limited by the speed of my cable modem (Your Mileage May Vary).
USB 2.0 Performance
The AX8817x chip set provides a USB 2.0 compatible implementation which runs at up to 480 Mbps (high speed), so it should be possible to keep up with 100 Mbps fast ethernet as long as there are no other slower devices on the same bus. To test this I copied a 64.8 MB music file to my PBG4 laptop connected through a LinkSys USB200M Ethernet Adaptor (en3) and compared this to the same file transfer using Built-in Ethernet (en0).
Both transfers reached 10 MBps (80-90 Mbps) and took about 10 seconds. I repeated the test in the other direction.
While the USB-To-Ethernet adaptor was slightly slower, at 80 Mbps there was little noticeable difference. Files moved quickly from one system to another via 100 Mbps fast Ethernet. Copying the same file using AirPort wireless took 50-90 seconds.
Stability
While other USB-To-Ethernet drivers are reported to be buggy, I havent encountered any stability problems to date. The adaptor turns off when the computer goes to sleep and comes back on when the computer awakes. It does not support "Wake On LAN" at this time.
Wrap Up
This USB-To-Ethernet Adaptor combination could be an attractive solution for a Mac Mini, or old iBook used as an Internet gateway or server. Im particularly fond of using old laptops as servers since they are compact, quiet, use little energy, and include their own battery backup.

Ethernal is a simple tool for visualizing all incoming and outgoing Ethernet packets. The source code of the application is available.
I wanted to learn how to read raw Ethernet packets on MacOS X. After going through several examples, I ended up writing this little piece of software. It uses the Berkeley Packet Filter device to read all incoming and outgoing Ethernet packets. I have wrapped the whole thing in a Cocoa GUI using the new bindings features of Mac OS 10.3.
Main features:
- Reads all incoming/outgoing Ethernet packets
- Displays the packet content in hexadecimal/ascii
- Finds any string in packet
- Filters packets
- Dynamic display width
- Save/load packets to disk.

Apple Ethernet speed & duplex tool 6.21a4 is an innovative and versatile unsupported system extension that allows you to disable the auto negotiation and set the speed (10 Mbit or 100 Mbit) and duplex (Full or Half) for the built in Ethernet of an Apple iMac, a Power Macintosh G3 (Blue and White version only), or a 1999 PowerBook G3 (Bronze version only). This is intended for use on both server and client Macintoshes. This software is intended for Mac OS computers that are directly connected to a switch port and have disabled auto negotiation on that port. Do not use this software if this does not apply to you. If you are unsure, contact your network administrator. Apple Ethernet Speed & Duplex Tool (Duplexer) is an unsupported tool and therefore is not supported by Apple Computer, Inc.

Requirements:
EtheRx PCI Ethernet (KNE40) card.

Enhancements:
Version 3.3b is now MacOS 9 compatible.

Requirements:
Fast EtherTX-10/100 PCI Plus Card

Requirements:
Kingston (KNE100TX) ethernet card.

Enhancements:
Version 3.3 is now MacOS 9 compatible.

Requirements:
Mac OS X 10.2 or later, Asante FriendlyNET GigaNIX 1000TA 10/100/1000BaseT Gigabit Ethernet PCI.