·:[ Jason On A Shtick ]:·
• • • • •

Saw this cake at a party… the dog is icing over peanut butter cake and the rug is a big sugar cookie.  Outstanding!

As a network administrator, I find that one of the most difficult and interesting questions to answer is What’s happening on the network right now? An open source tool called Cacti helps us answer that question.  Cacti has become one of our favorite open source products and is an indispensable tool for network monitoring.

In a nutshell, Cacti collects data using SNMP queries and other means, then stores that data and generates graphs of it using RRDtool.  Feed it some network device IP addresses, associate those addresses with device templates that determine the types of queries to run against them, and off you go. Here is an example graph of the switch port that is connected to our primary ISP link (click for larger version):

From this graph, we can easily get an idea of the traffic flow across the link both very recently and the trends over time. RRDtool is the data analysis muscle behind Cacti.  Cacti polls devices for data at a set interval, then RRDtool can employ both interpolation and consolidation of the data to generate the graph analysis.  So, it is important to understand that what you are seeing in a graph may deal in averages, min/max, etc.

Like any good open source tool, Cacti can be extended with plugins.  There are several useful plugins for Cacti such as MacTrack to watch for particular MAC addresses as Cacti polls your network devices and Threshold to alert you when a data point goes beyond a limit that you might care about.  Our absolute favorite plugin is Network Weathermap, which allows you to create an overview of your data in map form. Here is an example of our campus network map (click for larger version):

You can easily see how useful this map might be in answering that original question.  I wrote some script glue to save copies of this map as Cacti regenerates it at each polling interval, giving us a “history page” with links to saved map images. With this history, we can go back and look at the map for any five minute interval over the last week.

Getting Cacti configured and running with plugins and customizations is no trivial task.  There is a very active Cacti discussion forum on their site and lots of good documentation, plus your old pal Jason that can hopefully answer a question or two.

I recently purchased my first ever Apple computer for use at home – a vanilla 21.5 inch iMac.  Dallying with iPods and iPads seemed less of a sin, but I finally decided that I need to live with one every day in order to better understand and support them – you know, like a woman.   No falling back to the PC, either!  I’m moving all of my stuff to the Mac and riding it ’til it bucks me.

In a fairly short time, I had most of what I need up and running – Cisco VPN client, Microsoft RDP for Mac so that I can connect to stuff at work, moved my iTunes library over, synced the Mail app and iCal with GMail, Blackberry desktop to deal with my phone, Logitech software to program my Harmony remote control, Eclipse for my random development efforts and the Dropbox client (one of the first true cloud apps besides Google stuff that I’ve really found useful).  Oh, and I did indeed install a Flash player – the horror!

I had a couple of small hiccups but nothing major:

• When the Mail app synced with GMail, it sucked down all of the trash, created a label in GMail called “Deleted Messages” and applied it to all of those trashed messages.  This annoyance resulted in my poor Blackberry receiving over 200 trash e-mails that somehow looked “new” to it.
• The Address Book will sync with your GMail contacts, but only if you also sync the contacts on an iPod, etc with it.  Strange design choice here, but I was already syncing my iPod contacts with GMail over the air, so I simply changed it to sync with the Mac instead in order to magically populate the Address Book.
• There was one song in my iTunes library that apparently had too long of a file name for either the Mac file system or the ext2 file system on the D-Link DNS-323 NAS that was the go-between for file transfer from the PC.  iTunes complained about not being able to find that file, but I was easily able to point it to the mp3 with the shortened name.

I’m going to ride without anti-virus software for now just to see how that goes.  As an IT director, it miffs me a little to hear Apple people say that Macs are somehow safer and don’t require anti-virus software.  Macs are not safer because they are in some way better engineered, they are simply not a big enough target for the bad guys to aim at yet.  But as their market share climbs and there are more Macs out there, I’d expect to see some nasty stuff showing up on them.

At work, we’ve had success integrating Macs with Active Directory for authentication, dynamic DNS and file shares.  Domain controlled printers are another story, although that issue seems to be with the CUPS printing system, so Linux users can’t print to a domain printer, either.

Here’s to living how the other half (er, maybe ten percent?) lives.