The Joys of Fat Traffic

Wednesday, April 12, 2006, at 01:22PM

By Eric Richardson

Now that we're running our email on a server where we pay for bandwidth, I've realized I need to become a lot more conscious of how people use email. There's no excuse for busting up our 95th percentile just because someone's downloading or sending attachments.

This morning I saw a couple periods of pretty constant traffic into and out of the server, and judging by how the server bandwidth graphs correspond to the interface stats on the router, it seems that it's pretty much all traffic from the office. It's not a lot of users; just "fat" traffic from a few of them (attachments, perhaps).

Complicating matters is that the tools I would normally use to check out network conditions are all on Linux, and here at work it's all Macs.

The first tool I'd go to on Linux is etherape (which I first mentioned here on the blog over five years ago), to get a picture of where the traffic's coming from and going to. Running on the gateway machine you can get a really nice picture of both internal and external hosts, and what machines inside your network and generating your inbound and outbound traffic.

etherape, though, is a Gnome/GTK app. And while it's available through fink and it did compile for me, all I can get it to do is freeze after starting up.

ethereal, on the other hand, works just fine. It's much more a detail view than I'm looking for, though.

And with either of these I'd need to compile a remote listener to sit on the server and monitor the traffic there. That's certainly feasible, but it means figuring out how to install a development environment on that machine. Yuck.

For now I'm just planning to implement some basic traffic shaping (on both sides... here in the office and there on the server) and figure I don't care beyond that.