SSH jumping through multiple jump hosts

The standard OpenSSH SSH client accepts the argument -J to allow users to utilize a jump host/jump box.

What I recently discovered (and isn’t immediately obvious from the documentation) is that you can actually specify multiple jump hosts – separated by a comma – and the SSH client will jump through each single one in order to reach the target.

Read More

dig TXT whoami.ds.akahelp.net.

Core Backbone/AS33891 BGP Action Communities

A list of available action BGP communities for Core Backbone, AS33891.

Read More

Vultr List of Transits 2019/09

I compiled a list of Vultr transits per location into a spreadsheet

Read More

OVH test IPs

Recently I found a list of test IPs for various OVH locations.

Read More

“Why is my internet down?” | Analysis of a BGP leak causing a global outage

Explanation and analysis of today’s internet outage. What happened and what could’ve been done to prevent this?

Read More

Links I find useful

My list of links that have been useful to me in the past and I keep returning to them.

Read More

Making a GPU with an 8 pin work with a 6 pin power

Recently I had to swap my good old power supply for a spare one. However, I needed an 8 pin GPU power connector and the spare PSU had only a 6 pin. Turns out 6->8 pin conversion is not that hard to do.

Read More

Controlling a SIM800L modem

My quick notes regarding a SIM800L module on an inexpensive SIM800L EVB “SIM800LV2.2” carrier board from eBay. Communicates happily with a computer through a generic USB<>TTL converter, 5V logic levels and 5V power at 9600 baud. Carrier board includes a TTL level shifter and 2 diodes in series to drop the voltage from 5V to ~3.6V.

Read More

Fun with .arpa domains

As you may know, .arpa domains are used for reverse DNS. But did you know that they are usable for forward DNS too?

Read More