Hi, I recently added a feature to Zn servers to bind on specific interfaces. I got some questions about it, so here is a little writeup. A TCP/IP server socket used by an HTTP server is normally started by specifying the port on which it has to listen. This is how Zn normally works. Behind the scenes, the server socket is actually bound to what is called 'any interface'. TCP/IP on your computer / operating system, can have multiple network interfaces. Most have at least 2: one is called the local interface (lo, 127.0.0.1) and another is the TCP/IP address you are using to connect to the network and by extension the internet. Servers can have multiple network connections. By using the #interface: method, you can optionally control (or restrict) on which interfaces your Zn server should listen. In most cases this is not needed, but it can be an important security feature to only listen on the local interface (because that means the server can only be accessed from the machine itself, not over the network/internet). The default case is to listen to any interface available to the machine / OS. The following three are equivalent: (ZnServer defaultOn: 1701) logToTranscript; start. (ZnServer defaultOn: 1701) interface: nil; logToTranscript; start. (ZnServer defaultOn: 1701) interface: #[0 0 0 0]; logToTranscript; start. Next we bind only to the local interface: (ZnServer defaultOn: 1701) interface: #[127 0 0 1]; logToTranscript; start. Now, only http://127.0.0.1:1701 and http://localhost:1701 will work. On my machine (MacBook Pro, Mac OS X 10.7) I have the following network address: 192.168.1.6. This is how to listen to only that interface and not the local one. (ZnServer defaultOn: 1701) interface: #[192 168 1 6]; logToTranscript; start. Now, only http://192.168.1.6:1701 or (in my case) http://voyager.local:1701 will work. I have only tested this on my development machine with a Pharo Cog VM, but it should work cross platform. Let me know if that is not the case. Regards, Sven -- Sven Van Caekenberghe http://stfx.eu Smalltalk is the Red Pill