Cameron's Pensieve

Rdiff-Backup provides a fairly nice way of backing up a server, and I have used it to back-up a number of different servers, each with a different version of rdiff-backup. This is annoying because although a version 1.1.15 should work with 1.1.12, for example, in reality it does tend to complain.

Because of this version-skew on different types of servers, I took the approach of having multiple versions installed on the backup server (Mac OS X Panther in the first case, and now Leopard). This document details how you can house multiple versions of the rdiff-backup server on the same machine and use a different version per-client.

You can find the documentation and supporting files in the Files section.

What with all the hubbub with the OpenSSL faults in the news recently, I deciced I would do something to put down another large problem I have with a closely related product–OpenSSH, although I should immediately point out that this is not necessarily particular to OpenSSH.

You see, OpenSSH has very little support for easily creating rich access policies. The access policy I wanted to create was to allow password authentication to clients inside our campus, but only allow public-key authentication to clients coming from outside the network.

The reason for this, as anyone running an Internet-facing SSH server will be able to immediately appreciate, is that every day many login requests are made from the Internet to SSH servers, trying to brute-force account names and passwords; sometimes they are successful, but most of the time it just creates a lot of noise in the logs and an uneasy what-if feeling in your gut.

Read more...

I'm currently attending NZNOG'08, and the talks yesterday covered IPv6 Deployment. One of the topics raised was MPLS, which I only had the vaguest notion about what it was about, so I looked about for a useful quick tutorial. I found the following at SlideShare.net

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I have need to learn of RS-485 for the RFID project I am working on, as my fellow student/predecessor could not get it work right on Linux (we're using a RS485 to RS232 converter). Should be quite interesting... will have to look into the converter more, but must first learn about RS485. Turns out to be a very common data aquisition and control technique, and quite fast to boot. Lammert Bies has an informative article on RS485, specifications and in-depth tutorial.

I created a virtual tour of a structured cabling plant in Google Sketchup as part of an ethernet practical lab in TELE301. Enjoy, and I'd particularly enjoy feedback. I'm not particularly happy with the voice-over, I may redo that some time or add subtitles. I'd particularly like to hear from people in industry regarding building entrance facilities, particularly inter-building links.