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And you'll find some neat things like this: http://www.gns3.net/screenshots/ .

It's the can of worms popping open... You don't necessarily have to "buy" physical routers, switches, etc. These days, you can simulate pretty much any network setup you want via software and see how things work out: http://www.gns3.net/ Also, asking "us" what hardware you should buy is like asking someone what kind of computer you should buy, the question is too general and the answer will depend largely on the business/security needs of the company. Tannenbaum wrote a very good book about TCP/IP networking which you may want to read: http://www.amazon.com/Computer-Networks-Andrew-S-Tannenbaum/dp/0131651838 Aside from that, you should look into the basic requirements for network administration/security and make sure you understand and know how to apply them, the topics listed here could be a good starting point: http://en.wikipedia.org/wiki/CISSP

GNS3 is OSS. It runs best on a system with lots of RAM and a multi-core processor.

All you need beyond the initial download is a router image file (Cisco 7200, etc).

Enjoy!

GNS3 is OSS. It runs best on a system with lots of RAM and a multi-core processor.

All you need beyond the initial download is a router image file (Cisco 7200, etc).

Enjoy!

I use GNS3 located at http://www.gns3.net/ and it works very well and is very easy to learn and teach others to ues

Not a cure-all by any means, but one more trick for the toolbox. Very useful during a maintenance window. Obviously Cisco specific.

(tftp/scp/etc new-config to router)

router# reload in 2
router# copy flash://new-config run

(something along those lines, this is off the top of my head, basically copy your new config to the running config)

if it works, wr it to startup config, if you get disconnected, wait 2 minutes for the router to reboot and automatically load the previous startup-config. Adjust the time as necessary depending on change/complexity.

Also use something like RANCID or KiwiCatTools to help handle managing your configuration changes.

But the best trick of all is using a full blown router emulator like gns3.

It's a MIPS emulator that loads unmodified IOS images. You can build complex scenarios and even attach them to NICs on the host PC. I've built labs with several routers attached to bridged NICs in VMWare guests. So you can literally start, say, a webserver on one vmware guest and access it across your gns3 "network". You can also bridge it to physical NICs -- you could have a 7206vxr router running on an old PC!

Plenty of limitations. Namely it can only run a specific set of IOS images for specific models and you have to use an NM-16ESW to simulate switching since switching is done in ASICs.

Here are a few tools:

GNS3 - http://www.gns3.net/ - free network simulator, based on Dynamips Cisco emulator
Opnet - http://www.opnet.com/ - detailed planning of networks, from scratch
Traffic Explorer - http://packetdesign.com/ - plan changes to an existing network

Specifically, GNS3 allows you to create test networks in a virtual environment, then import software images for your Cisco routers, switches, PIX firewalls, Juniper hardware, etc, all run on hypervisor technology.

For anyone unfamiliar with GNS3, a link to the website. There are versions available for Windows, Linux, and OS X. FreeBSD already has it in ports.

As a side note, I'd add that maintaining a home lab (to the extent practicable and useful) is one way to side-step limitations of what your employer provides. Consider it a combination of "Ongoing Professional Education" and "Proactive Job Security Measures" (i.e., "I better test this shit to save my ass tomorrow").