poor man’s ruptime

Historically it is using broadcast udp/513 [3] in a network. So this is a test how many machines it can take.

$ ruptime
fish             up    4+21:27,  0 users,  load 0.22, 0.25, 0.25
tuna             up    4+21:27,  0 users,  load 0.20, 0.25, 0.25
dolphin          up   15+05:57,  0 users,  load 0.04, 0.08, 0.07

• it's simple [4]
• monitoring systems have no or not very useful CLI tools
• you don't want to manually keep a list of hosts
• you want to see what hosts are down
• you want to see what hosts are not idle
• you want to run something on all running hosts with parallel

• allow to monitor custom variables
• web presentation/views

The defaults for rwhod/ruptime is downtime after 11' (11*60 seconds) [1] (ISDOWN), status messages are originally generated approximately every 3' (AL_INTERVAL) [2].

SERVER=wedonthaveaprivacyproblem.com
PORT=51300
HOSTNAMECMD='hostname -f'

Create a key for the encryption with mcrypt. You will need this on server and client for symmetric encryption.

COLUMNS=160 dd if=/dev/urandom bs=1 count=60 2>/dev/null > /etc/ruptime/ruptime.key

• Client: nc mcrypt
• Server: nc xz tcputils daemon mcrypt
• Optionals: pen trickle

• macOS
• Linux
• FreeBSD
• Windows if someone implements uptime.exe (https://www.windowscentral.com/how-check-your-computer-uptime-windows-10#check_pc_uptime_cmd)

• FreeBSD: rc.d
• Linux: daemon, init.d, cron @reboot, systemd [5]
• macOS: https://medium.com/swlh/how-to-use-launchd-to-run-services-in-macos-b972ed1e352
• Windows (not sure if they still have net start, haven't seen it since NT 4)

crontab -l
*/3 * * * * /usr/bin/ruptime -u

[1] https://sources.debian.org/src/netkit-rwho/0.17-14/ruptime/ruptime.c/

[2] https://sources.debian.org/src/netkit-rwho/0.17-14/rwhod/rwhod.c/

[3] https://manpages.debian.org/unstable/manpages/services.5.en.html

[4] https://www.gkogan.co/blog/simple-systems/

[5] https://kill-9.xyz/harmful/software/systemd