Happy new year, all. I’m finally over my hangover from the party and ready to blog. Everywhere I go, I always wind up in a debate about how to alert on log messages as they come in. I was at the grocery store yesterday, and the cashier told me that she had a list of […]
Stretch at Packetlife has a lively little write-up on the Australian government’s attempt to implement a nation-wide web filtering service. From Packetlife.net: Setting aside the myriad of technical barriers to implementing such a system, the most obvious question is, “who decides what gets blocked?” When a corporation implements a web filter, it does so in […]
I thought I’d throw an easy one out before taking off for the holiday. Merry Christmas, Hannukah, Kwanzaa, Saturnia, etc., to all. A few years ago, I was looking through some Cacti graphs of gigabit trunks between 6500s and noticed an abrupt change in traffic. The graphs were nice and smooth at around 135Mpbs until, […]
A few articles ago, we discussed getting logging up and running on your IOS box. Part of the discussion was actually having the device log remotely to a box somewhere, but that’s kind of worthless without a properly (for definitions of proper) configured syslog server. A low-end Linux box with an appropriate amount of disk […]
I like logging on an IOS device. I like to look at the buffer and tell you that your interface went down 30 seconds ago. I like to look on the box and see that BGP with my Internet provider has been flapping since 02:13ET. I like to look and see that one of the […]
Alright, that’s an exaggeration, but screen is pretty freaking cool. It’s an app that’s (usually) run under Linux that lets you run commands then detach from that session and reattach later. It doesn’t seem like much, but a few examples can show what it does for me. I have a backup script at home that […]
Here’s a quick one for you. In Dynagen, if you want to load a configuration when you first fire up the router instance, you can use the cnfg tag in your NET file like this. cnfg = /home/jac/labs/cfg/R0.cfg If you put that in your dynagen NET file under a router, the contents of that file […]
If you’ve never used TCPDump before, you’re missing out on one of the best parts of being a network guy — pointing fingers at everyone else. TCPDump is an open-source app that copies packets on a machine’s NIC to screen or to file. TCPDump is typically a Linux/Unix app; in the Windows world, TCPDump is […]
Let’s talk [tag]audit[/tag]ing for a bit. It’s important to have an outside person look over your [tag]configuration[/tag]s every so often to be sure you didn’t do something stupid, so, every quarter or so (mostly so), I bring in someone to…wait a minute. It would cost about $3000 for someone to do that, and the company […]
We all have limited budgets these days. Long gone are the days of unlimited resources and uncontrollable expansion of the network, so it’s important that any network dude or dudette pay attention to the open-source world. Below is a list of stuff I use at the office and at home to monitor, trend, and alert […]