Author Archives: Lasse Karstensen

Some IPv4 address price forecasting

I spent some time playing around with forecasting second-hand IPv4 range prices the other day. ARIN is the most liquid, so the price development is best seen there: RIPE has a worse fit, but shows the same trend: I’m wondering … Continue reading

Posted in Uncategorized | Leave a comment

Scaleway Centos7.2 image is vulnerable

UPDATE 2017-11-09: Torgrim Teigstad originally reported this and did some additional testing this week. It appears that all VMs spun from this image use the same hard coded root password, and this exists in the list of passwords being probed … Continue reading

Posted in Uncategorized | Leave a comment

Doing consulting work

I’ve been working as an independant consultant since January 2017. I left my position as tech lead with Varnish Software, having spent almost five years there, knowing it was time to do something else. I’d like to thank Poul-Henning for … Continue reading

Posted in Uncategorized | Leave a comment

fdxread 0.9.1 released

I’ve released version 0.9.1 of my Nexus FDX protocol decoder. It does things like read .nxb files a lot quicker than before, handle USB disconnects/reconnects of the GND10 (when running), serial port timeout, and lots of other stuff. As of … Continue reading

Posted in sailing | Tagged , , , , | Leave a comment

Garmin GND10 unveiled (it is Nexus FDX!)

Mother of all detours; the USB port on the Garmin GND10 isn’t NMEA2000, it is something called Nexus FDX. That took a couple of weeks to figure out, hunting for NMEA2000 protocol headers. Always check your assumptions. Anyway, I’ve written … Continue reading

Posted in sailing, varnish | Tagged , , , , , , | 10 Comments

NMEA2000 and CANbus

I’ve been looking at NMEA2000 and CANbus lately. I’m attempting to reverse engineer the binary protocol seen coming out of the USB port on a Garmin GND10 network bridge, and that opens a whole field of new and interesting stuff … Continue reading

Posted in stuff | Tagged , , , , , | Leave a comment

Scanning for multicast TV channels

In recent times, I’ve cut the cord and stopped watching TV from my local cable company. This gave the need to look for IPv4 multicast groups that had active talkers, so I (on occasion) could stream some live TV over … Continue reading

Posted in Uncategorized | Leave a comment

Introducing hitch – a scalable TLS terminating proxy.

The last couple of weeks we’ve been pretty busy making SSL/TLS support for Varnish Cache Plus 4. Now that the news is out, I can follow up with some notes here. The setup will be a TLS terminating proxy in … Continue reading

Posted in varnish | Tagged , , | Leave a comment

PROXY protocol in Varnish

Dag has been working implementing support for HAProxy’s PROXY protocol[1] in Varnish. This is a protocol adds a small header on each incoming TCP connection that describes who the real client is, added by (for example) an SSL terminating process. … Continue reading

Posted in varnish | Tagged , , , , , | Leave a comment

Announcing libvmod-tcp: Adjust Varnish congestion control algorithm.

I’ve uploaded my new TCP VMOD for Varnish 4 to github, you can find it here: http://github.com/lkarsten/libvmod-tcp. This VMOD allows you to get the estimated client socket round trip time, and then let you change the TCP connection’s congestion control … Continue reading

Posted in varnish | Tagged , , , | Leave a comment