I finally took some time to check out Capirca. It may be useful.
Posts Tagged ‘ linux ’
An Interesting Problem with Multiple DCs on a Stick
We talked about running multiple data centers on a stick back in August, which is where you have multiple logical pairs of client and server VLANs on a single CSM for different tiers or functions. The big point of the article was that you had to do some fancy forwarding to get a server-initiated...
VLANs on Linux
My home network has a Linux box running IPTables as it’s center point, and, since there are four networks, it has 4 NICs and 4 cables into the switch. I kept running into problems with the NICs (they would reorder depending on what flavor of Linux was installed), so I wanted to consolidate the...
Unix Epoch + 1234567890 = Next Friday
I’m kind of an obsessive-compulsive when it comes to numbers (1, 2, 3, 4, 5…), so I’m fairly excited about next Friday (..6, 7, 8, 9, 10…) when Epoch time reaches 1234567890 at 18:31:30 on 13 February(…11, 12, 13, 14, 15…). I’m sure my ADD will kick in (Oh, look. A squirrel!) right before,...
Leap Second
Did anyone notice (or care about) the leap second? I did neither. Here’s some cool output from Kevin Oberman on the NANOG list, though. bash-2.05b# date Thu Jan 1 00:59:58 CET 2009 bash-2.05b# date Thu Jan 1 00:59:59 CET 2009 bash-2.05b# date Thu Jan 1 00:59:60 CET 2009 bash-2.05b# date Thu Jan 1 01:00:00...
Free and Awesome Network Tools
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...
A Simple BGP Lab with Dynamips/Dynagen
I assume you take every word I say to heart and that you’ve been using Dynamips/Dynagen for a few days now, right? Good. That’s a start, but let’s break down a simple lab to make sure everyone’s on the same page. I run my labs on Linux most of the time, so you’ll see...
Finding Hosts on Layer 2
Most firewalls should block ICMP requests to them, so how do you know that your router or server has layer-2 connectivity to one? It’s pretty elementary, actually, but I’ve found that not a lot of people know this trick. If you ping the firewall, it will receive the ICMP packet and drop it per...
Using a Linux Box as a File Server
Ever heard of Samba? You should. Samba is an open-source project “that provides seamless file and print services to SMB/CIFS clients.” That’s from the project’s website, but what the hell does it mean? In a nutshell, it’s an open-source application that lets non-Windows machines share files and printers with Windows machines. In most cases,...
Port Knocking
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 detects the sequence of packets that you send and runs a script (usually IPtables commands), waits...
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