Running Mac OS X Tiger

Active Network Connections

To dig a bit deeper, you can take a look at all the active network connections on your machine. To do this, use the same Netstat tab in Network Utility, click the radio button next to “Display the state of all current socket connections,” and the hit the Netstat button. It usually takes a few seconds to generate the result, which is shown in Figure 11-8. This displays the same information as typing netstat -a into a Terminal window, shown in Example 11-7.

Example 11-7. Some output from netstat -a

$ netstat -a
Active Internet connections (including servers)
Proto Recv-Q Send-Q  Local Address          Foreign Address        (state)
tcp4       0      0  192.168.79.9.50836     192.168.79.5.993       ESTABLISHED
tcp4       0      0  192.168.79.9.49932     192.168.79.5.993       CLOSE_WAIT
tcp4       0      0  192.168.79.9.49894     192.168.79.5.5900      ESTABLISHED
tcp4       0      0  192.168.79.9.49593     17.250.248.64.993      ESTABLISHED
tcp4       0      0  *.*                    *.*                    CLOSED
tcp4       0      0  192.168.79.9.49225     205.188.7.200.5190     ESTABLISHED
tcp4       0      0  *.*                    *.*                    CLOSED
tcp4       0      0  127.0.0.1.1033         127.0.0.1.925          ESTABLISHED
tcp4       0      0  127.0.0.1.925          127.0.0.1.1033         ESTABLISHED
tcp4       0      0  *.*                    *.*                    CLOSED
tcp46      0      0  *.6942                 *.*                    LISTEN
tcp4       0      0  *.6942                 *.*                    LISTEN

Figure 11-8. Using Network Utility to examine network connections

Each item in the list shows the local and remote addresses and ports in the form host . port where the port name is translated, if known, into a service name such as http or