Security for Unmanned Devices
·2 min read
I was talking to a coworker the other day about setting up his home network more securely. “No problem,” I said, and we started listing devices on his network to see what we needed to do. …
Posts
Running HSRP for Availability
·3 min read
In the article describing a router-on-a-stick, I mentioned that I would use two routers that run HSRP for availability, so I figured that I would write up a short post on what it is and how it works. …
Router-on-a-Stick
·3 min read
Ever heard of a router-on-a-stick? Go ahead and laugh…everyone does. It’s a funny name for a very serious topic, though. A router-on-a-stick is a network configuration that uses a single …
Common Cisco IOS Commands
·2 min read
Here’s a list of IOS commands that I use all the time that aren’t a part of the basics. I obviously use more than just these, and you do, too, but I hope there’s at least one …
Separation of Function
·2 min read
Separation of function is another important security concept that people often overlook. It can mean that a single person is only responsible for one part of a process. Or it can mean that one server …
Fallback IPtables
·2 min read
The hardest part of messing with firewall configs is knowing what is going to lock you out of the firewall itself. It doesn’t to me very often, but I’ve been doing firewalls for 10 years …
Port Knocking
·2 min read
A few months ago, a friend of mine told me about the concept of port knocking, where you send packets to a server on certain ports to authenticate access to the box. A daemon running on your server …
Mixed-platform LANs and Spanning Tree
·2 min read
We just an HP C-class blade chassis which included two GbE2c network modules. These modules are Nortel switches running AlteonOS that connect the blades to the rest of your network. When I turned …
The Principle of Least Privilege
·1 min read
The Principle of Least Privilege says that users or applications should only have access to the what it needs to access and that access should be as limited as possible. This idea can be applied to …
Using an Old Server as a Home Firewall
·3 min read
You can use an old PC as a firewall at home (and at work, I guess). It’s not that hard to do if you have a basic knowledge of Linux, DHCP, and IPtables, but that may be saying a lot. Why would …