Links about system administration. "System administration is what you didn't count on when you decided to self-host."
#Bookmarks
A cheat sheet for popular SSH commands, key generation, SSH agents – SSH - Cheat Sheet
Help fight email spam:
For domains that don’t send email, here’s how to set up DNS records: set SPF record, set rejecting DMARC record, set DKIM record, set null MX record. – Protect domains that do not send email
Protect domains that do not send email
Encrypted disks:
My workstation uses LUKS to encrypt the underlying filesystem on two SSDs (NVMe) devices, atop of which I have lvm2 running to create a big filesystem, which worked nicely the last couple of years (more details will follow below). But after the upgrade from Debian 11 (Bullseye) to Debian 12 (Bookworm) my system refused to boot. – Fixing broken boot from encrypted devices after upgrade to Debian Bookworm by @schaueho@functional.cafe
Fixing broken boot from encrypted devices after upgrade to Debian Bookworm
Display managers:
@aral@mastodon.ar.al recently recommended:
Terminal Trove is something to investigate, later.
@evenreven@ruby.social added:
I've gone from ranger to nnn to fff to lf to yazi, and yazi is my favourite so far.
I have tried mc, ranger and nnn – and I still prefer Emacs.
@leonerd@fosstodon.org wrote about dual stack hosts (IPv4 and IPv6, like this server):
TIL that `ssh` doesn't implement HappyEyeballs. If it thinks it has IPv6 connectivity but the upstream router doesn't work, it'll just sit there never making progress, never failing back to 'v4 instead. You have to manually `ssh -4` or `ip -6 ro del default` to get around that bug.
Other replacements for traditional tools:
Port scanning:
The purpose of this guide is to introduce a user to the Nmap command line tool to scan a host or network to find out the possible vulnerable points in the hosts. You will also learn how to use Nmap for offensive and defensive purposes. Let us see some common and practial nmap examples running on Linux or Unix-like systems. – Nmap Command Examples For Linux Sys/Network Admins, by Vivek Gite, for nixCraft