Sat 23 Jan 2021

Tutorial: Troubleshooting Linux SSH Login Delay

I’ll start from a relatively simple problem - logging in to a server via SSH always takes 10 seconds. The delay seems to be pretty constant, there don’t seem to be major network problems and the server is not overloaded. Yet, remote logins always take 10 seconds.

If you’be been around, you probably already know a couple of likely causes for this, but I want to approach this problem systematically. How to troubleshoot such issues without relying on lucky guesses or having previous experience with usual suspects. You never know, next time the root cause may be different - or you have to troubleshoot a completely different application.

Source: Tutorial: Troubleshooting Linux SSH Login Delay - Why does logging in always take 10 seconds?, an article by Tanel Põder.

Monoids etc

Monoids are simpler than categories. A monoid is defined by a collection (set) of elements and an operation that allows us to combine two element and produce a third one of the same kind.

Source: Category Theory Illustrated - Monoids, an article by Boris Marinov

Command PATH security in Go

Today’s Go security release fixes an issue involving PATH lookups in untrusted directories that can lead to remote execution during the go get command. We expect people to have questions about what exactly this means and whether they might have issues in their own programs. This post details the bug, the fixes we have applied, how to decide whether your own programs are vulnerable to similar problems, and what you can do if they are.

Source: Command PATH security in Go, an article by Russ Cox.