Monitoring Network Traffic

This may apply to OS X only, but maybe Unix/Linux as well.

My DSL service is pretty low end by today’s standards, around 786K bandwidth compared to the bazillion G per second of FIOS or whatever.  It’s always been fine, you only really notice its low end when downloading something really big like streaming HD video services.  But, not doing that a whole lot so its been generally unnoticeable.  Lately, thought, its starting to show signs of being not-enough.

I think the problem is that over time I’m adding devices, and along with that, those devices are doing more things on-line that I’m not conscious of.  I was wondering why page refreshes were so sluggish, then I noticed that the lights on my hub were blinking away even though I thought nothing was going on.  So, how do I see what’s going on?

Googling around found this:

http://www.cultofmac.com/158061/see-what-your-network-traffic-is-like-using-the-terminal-os-x-tips/

Very useful, I now can see what’s going on, although frequently in cryptic daemon process labels.  But, some are very useful, especially when you see a ton of activity from Apple software update services, which was not an active application at the time.  I expect this program to poll the mothership for updates when I ask it to, I didn’t expect it to download those many-megabyte files until I told it I cared about the download.

If you open up Software Update, you’ll notice as you go through the entries that some of them indicate “downloaded” status.  If you have a lot of bandwidth, not bad, you didn’t have to wait for the download for processing.  But, if you don’t, you might want to control the time when this activity is happening, so you’re not clogging up the pipe when you are doing something more important.

Fortunately, there is a control panel to deal with this.  Note the check box below “Download Updates Automatically”.  Go ahead and uncheck this if you want to control this.  The down side; if you see some update you want to process, clicking “install” will start up a download process you need to wait for.  Not fun for that 163 M iTunes update (what the heck is in that?) or that close to a Gig OS X update.

Other solutions are out there.  A number of links led to a program called Little Snitch.  Seems like a nice program, just does a lot more than answer the basic program.  If you’re roaming around a lot might be worth looking at.