Workshop

the Hummingbird client has been installed on the PC.
There’s also no graphical setup. You must configure the client by editing the SOCKS.CNF file in your
Windows system. Here’s an example of how I might set up a Hummingbird configuration file for a
simple two-segment network:
Direct 192.168.1.0 255.255.255.0
Direct 192.168.2.0 255.255.255.0
@SockD4 = 192.168.2.10 0.0.0.0 0.0.0.0
In a nutshell, this file means that you’re directly connected to 192.168.1.0 and 192.168.2.0.
Traffic to those segments will not use the socks server. All other traffic will be passed to the socks 4
server at 192.168.2.10.
In a nutshell, Hummingbird’s client is extremely configurable yet hard to configure, and it adopts a “grab
everything that goes on in the network and deal with it according to my configuration file” policy.
Although this client works with more applications than does the NEC client, it affects all rather than
some applications you run. The NEC client, on the other hand, is less intrusive, more friendly to
configure, requires a separate configuration for each application, and sometimes doesn’t work for certain
applications because it is less intrusive.
Let’s take a look at some common toys; you can apply the techniques used for these to other fun apps.
We’ll start with simple examples and get more complex as we go.
AOL Instant Messenger
Okay, what’s the deal here? What is AIM? AIM is a fun way for folks to talk back and forth across the
Internet in real time. However, it wants you to establish a TCP connection to one of AOL’s servers in the
field, and your firewall may be preventing this.
Make sure that your firewall allows TCP socket 5190 on an outgoing basis (it does if your firewall policy
is to allow everything from the inside to go out). If you have a socks or HTTPS (HTTP Secure) proxy
server, no problem. As you can see in Figure 20.2, the setup screen for AIM gives you the option to
configure it for these types of proxy servers. It’s very friendly.