Main Help Page
Network

# Optimization

To optimize the network:

1. Choose a network card in the drop down menu.
2. Set the speed and if applicable the duplex for the network card.
3. Choose a connection type in the drop down menu.
4. If applicable set MTU, kernel socket buffer, TCP, UDP and Local stream sockets values.
5. Press the "Apply" button
6. Done!

Choose network card: (1-2)

The first step in optimizing the network card is to select which card you want to use. Primary (en0) is usually an Ethernet card, the secondary (en1) is usually the Airport card. Cocktail also have support for en2, en3, en4, fw0 and fw1. Cocktail provides an indicator which displays the current card's adapter status.
When an active network adapter is chosen you can set the speed (Auto select, 10BaseT/UTP, 100BaseTX and 1000BaseT) and duplex to Half, Full, Full with hardware-loopback or Full with Flow-control. These settings are only available for Ethernet cards as Airport and Firewire network adapters do not allow these to be modified.
Cocktail also allows you to force speed and duplex settings. Forcing invalid speed and duplex settings can result in communications problems, however the original settings can always be restored from Cocktail. When "force speed and duplex settings" is disabled, Cocktail will try to use chosen configuration. If that fails Cocktail will automatically change speed and duplex to a valid setting.

Choose connection type: (3-4)

When a network card has been selected the next step is to set the connection type. You can choose between a set of predefined types or create a custom connection type. Besides the default and custom option the following predefined connection types can be chosen in the list:

- Dial-up (PPP)
- Bluetooth (GPRS/EDGE)
- Satellite (up to 1Mbps)
- Satellite (over 1 Mbps)
- DSL (PPPoE)
- Fiber (FiOS)

Cocktail also allows you to define MTU size and kernel socket buffer size (kern.ipc.maxsockbuf).
TCP
Receive window size: net.inet.tcp.recvspace
Send window size: net.inet.tcp.sendspace
Slow link window size: net.inet.tcp.slowlink_wsize
Delayed ACK: net.inet.tcp.delayed_ack
RFC-1323 extensions: net.inet.tcp.rfc1323
UDP
Outgoing datagram size: net.inet.udp.maxdgram
Receive buffer size: net.inet.udp.recvspace
Local stream sockets
Receive buffer size: net.local.stream.recvspace
Send buffer size: net.local.stream.sendspace

Apply settings: (5-6)

When pressing "Apply" Cocktail will apply all settings and create a "startup item" in /Library/StartupItems which restores the network settings a reboot. By creating a startup item Cocktail solves the problem with configuring Mac OS in the Terminal or by using Network preferences where these changes are set to default on reboot.
If you encounter problems after changing the network settings with Cocktail (i.e. selected Dial-up preset when a DSL connection is present) you can remove the folder /Library/StartupItems/Cocktail and reboot the computer. If OS X prevents you from delete the folder OS X can be booted in SafeMode by pressing and holding Shift while your Mac is booting.

Online information

- Starting up in Safe Mode by Apple.