First you must remove any other Realtek driver you may have installed.
Common ones are: RealtekRTL81xx.kext RealtekRTL8000SL.kext AppleRTL8169Ethernet.kext
It is possible that these kexts are installed under directly in /System/Library/Extensions or under /S/L/E/IONetworkingFamily.kext/Contents/PlugIns, so be sure to check both locations.
Next, install the kext using Kext Wizard or your favorite kext installer.
Special note for Snow Leopard users: There is a conflict between the RTL8169 driver that is part of Snow Leopard and this driver. The RTL8169 driver, during its probe method, puts the hardware into a bad state where it cannot be detected properly by this driver. As a result, you must remove it:
sudo rm -rf /System/Library/Extensions/IONetworkingFamily.kext/Contents/PlugIns/AppleRTL8169Ethernet.kext
Note: The current v2 build supports only Mountain Lion 10.8 or newer.
Downloads are available on Bitbucket:
https://bitbucket.org/RehabMan/os-x-realtek-network/downloads/
Note: Archived (old) downloads are available on Google Code:
https://code.google.com/p/os-x-realtek-network/downloads/list
My build environment is currently Xcode 6.1, using SDK 10.6, targeting OS X 10.6.
This kext can be built with any of the following SDKs: 10.8, 10.7, or 10.6 but only by enabling the hacks previously used in the code (see DISABLE_ALL_HACKS in the source code)
In addition, it can be built supporting any of these OS X targets: 10.8, 10.7, or 10.6.
For greatest compatibility, the provided build is SDK 10.6 targeting 10.6.
This project does not support 32-bit builds. It is coded for 64-bit only.
The source code is maintained at the following sites:
https://github.com/RehabMan/OS-X-Realtek-Network
https://bitbucket.org/RehabMan/os-x-realtek-network
Mieze's original repository is now on github:
https://github.com/Mieze/RTL8111_driver_for_OS_X
Please use the following thread on tonymacx86.com for feedback, questions, and help:
http://www.tonymacx86.com/hp-probook/93732-new-kexts-proposed-probook-installer-v6-1-a.html
http://www.insanelymac.com/forum/topic/287161-new-driver-for-realtek-rtl8111/
2014-05-26 (RehabMan)
Pulled latest changes from Meize
Please note that the default build for this project is the v2 project which supports only 10.8+ That means versions prior to 10.8 are not supported (eg. Lion/SL). You can still build the v1 kext if you wish.
2014-10-16 (RehabMan)
Pulled latest changes from Mieze
Build with Xcode 6.1
2013-04-25 (RehabMan)
2013-04-17 (RehabMan)
Pulled latest changes from Mieze
Removed hacks previously necessary for running on SL/Lion
Now using SDK 10.6
Now exporting public functions from RTL8111 class (better compatibility with SL)
2013-03-22 (RehabMan)
Modified for single binary to work on ML, Lion, and SL.
Optimize build to reduce code size and exported symbols.
2013-03-17 (Mieze)
This repository contains a modified version of Mieze's Ethernet driver for Realtek RTL8111 series chips. All credits to Mieze for the original code and probably further enhancements/bug fixes.
Original sources came from this post on Insanely Mac:
http://www.insanelymac.com/forum/topic/287161-new-driver-for-realtek-rtl8111/
My goal in creating this repository was just to create a single binary that could be used on 10.8, 10.7, and 10.6 for use in the Probook Installer.
I also added the CLEAR_STATUS_IN_INTERRUPT "feature/bugfix" which fixes some performance issues I was experiencing on my ProBook to SMB shares. In addition, a few other changes were made to allow the code to compile on 32-bit (no idea if that is still the case).
RTL8111 Driver for OS X
OS X open source driver for the Realtek RTL8111/8168 family
Please note that this driver isn't maintained by Realtek!
Due to the lack of an OS X driver that makes use of the advanced features of the Realtek RTL81111/8168 series I started a new project with the aim to create a state of the art driver that gets the most out of those NICs which can be found on virtually any cheap board on the market today. Based on Realtek's Linux driver (version 8.035.0) I have written a driver that is optimized for performance while making efficient use of system resources and keeping the CPU usage down under heavy load.
Key Features of the Driver
Limitations
Installation
Before you install the driver you have to remove any installed driver for RTL8111/8168.
Goto /S/L/E and delete the old driver (Lnx2mac, AppleRealtekRTL8169, etc.).
Recreate the kernel cache.
Open System Preferences and delete the corresponding network interface, e. g. en0. If you forget this step you might experience strange problems with certain Apple domains, iTunes and iCloud later.
Reboot.
Install the new driver and recreate the kernel cache.
Reboot
Open System Preferences again, select Network and check if the new network interface has been created automatically or create it manually now.
Configure the interface.
Current status
The driver has been successfully tested under 10.8.2 - 10.8.5 and 10.9 with the D (chipset 9), E (chipset 16) and F (chipset 17) versions of the RTL8111 and is known to work stable on these devices but you'll have to consider that there are 25 different revisions of the RTL8111. The RTL8111B/8168B chips have been reported to work since version 1.0.2 too.
Changelog
Known Issues
Building from Source
I'm using XCode 4.6.3 for development. You can get a free copy of XCode after becoming a member of the Apple developer program. The free membership is sufficient in order to get access to development tools and documentation.