Although this isn't an OS X specific tip, if you do much with the built-in UNIX-based services in OS X (such as SSH, Apache, and FTP), it may be relevant. These services operate over ports, which are defined and managed by IANA (Internet Assigned Numbers Authority). If you'd like to familiarize yourself with who they are and what they do, just visit their web site.

If you'd like to see a very exhaustive list of port assignments, IANA is the place to go. This list is the most exhaustive that I've ever seen. This can be useful for things such as establishing 'port forwarding' in a router, which will allow certain ports (such as 548, for Appletalk over TCP) to be sent through your router to one target machine (your Mac running OS 9 file sharing over TCP/IP).

If you are a "power user" in the Mac OS 9 world, and you want to delve into all the services that are offered with OS X, some knowledge of port numbers may be helpful as you start experimenting with Apache, SSH, FTP, Samba, etc. For the typical OS 9 convert, though, you won't have to know anything about them -- other than they're out there, and they help make some of the cool stuff in the new OS possible.

This thread over on the MacNN forums discusses how to mount your iDisk using a terminal session. Why might this be useful? You could SSH to your OS X machine from anywhere, mount your iDisk, and then use cp to copy files from your iDisk to one of your local drives ... with the new "Apple Software" folder on iDisk, this could prove to be very handy!

I've documented the "how-to" in the second part of this posting, but head over to MacNN to read the full details!

Accessing your idisk (given to you when you sign up for itools) is quite easy under OS X.

When in the finder, select Connect to Server under the Go menu (or just press command-K). When the dialog box appears, make sure the drop-down menu says AFP Servers, and then type idisk.mac.com in the URL entry box.

A username/password dialog box should appear. Enter your mac.com username and password, and your idisk should mount on the desktop. Once it's mounted, you can make an alias to it, and simply double-click it in the future.

Apple has added a new "Software" folder to everyone's idisk which contains a selection of OS X software disk images. To use, simply drag the image you want onto a local volume and it will download. There's a large number of programs listed, and I imagine this folder will get much more active once OS X 1.0 ships. Quite cool, and this alone probably makes it worth getting a (free) itools account.

Thanks to 'James' for submitting the idisk question!

Does anyone know if OS X is going to support NFS v3 or v2?

[Editor's note: See the comments for the answer!]

My friend is running DHCP at his house. I noticed that it also assigns an Host name to OS X. How do I override this host name? While DHCP is enabled, the Host name field is grayed out.

[see the comments for a solution]

If you are an IRC user, and you notice that your identd function only seems to work when you're logged in as root, head on over to this thread on the MacFixIt forums for a quick edit fix to make it functional again.

I've also noted the how-to in the body of this article just for posterity, but please, support all the Mac sites by reading the original over on MacFixIt!

TCP Wrapper allows you to protect your machine's daemon, such as FTP, telnet, etc. It's a filter that use IP numbers and hostnames to restrict access. TCP Wrapper is already in MacOS X, but the configuration file is not provided, so there is no protection at all, and there won't be until you create one and edit it to suit your needs.

You can see a sample hosts.allow file at this URL:

http://www.patpro.net/images/hosts.allow

Copy this file into /etc/ and edit it. How to configure the file is pretty obvious as soon as you take a look into it so I don't detail this part (the file is commented with basic instructions).

WARNING: Be really careful when working on a remote machine, messing up the hosts.allow can prevent you from connecting again to that computer.

One giant step backward for OS X (beta, at least) is the need to restart when you tweak the network settings. This was always something I was able to mock Windows for - touch the Network control panel, reboot.

Luckily, UNIX gives the power to get around this (for the most part, there have been reports that not all pieces are restarted).

Contributed to osxfaq.com, this article explains how to create a stop and restart shell script for network services.