Meetups/Infra/2025-11-10

a walk through ssh keys, agents, and uses (aside for cht.sh) -- motivating problems for http/3 + quic new transport layer protocol -- brief demo of LEAN4 via the natural number proof game

Introductions

• [name] - [background]. [goals for meetup, or interests to explore]

• Loren -- talk to me about
• Mister Name/Kevin - likes computers/AI/coding, here to learn
• Maksym - from Poland, likes infra, data mining with LLMs, prefers to code than talk
• Lulu - came here to learn
• Erik - focused on hardware
• Doug - like computers
• Max - likes computers, here to learn
• Cole - ^, + linux guy, chemistry
• Alex - does AI stuff
• Michael - devops + hosting
• Rolando - work with language ...
• Robert - interested in any type of tech
• Frank - does mostly software, interested in infra
• Derek - verified parser / micro containers
• Robbie -
• Elan - interested in scalable...cloud stuff. Like running more than one cpu. Needlessly complicating project XD

Lesson or Demo

• Read aloud: clarify for meetup. We are taking notes in a riseup pad (or I am--help appreciated, and links). We have meeting notes posted to the wiki. noisebridge.net, search Infra, or Meetups/Infra. (the Infrastructure page has a disambiguation link.)
• Shell, web services, self-hosting, networking!

• • ssh-agent tech (19:30 - 19:40) - stores your private key's passphrase for a duration, easing sshing into remote machines through the day.
    • Start ssh-agent using: eval $(ssh-agent)
    • Add your private keys to the agent: ssh-add ~/.ssh/id_rsa
    • List added ssh keys with: ssh-add -l
    • Remove a key: ssh-add -d <key id>
    • Remove all keys: ssh-add -D
    • downside: secure the computer on which you are running ssh-agent, your added private keys will be accessible without passphrase. i.e. don't leave your laptop unlocked while you get another espresso at Cafe Trieste

• • cht.sh: cheatsheet tool, e.g.

$ curl cheat.sh/ls - info about 'ls' file list utility
$ curl cht.sh/btrfs - info about the btrfs filesystem
$ curl cht.sh/tar~list - info about tar file utilities (Tape ARchive, early archive file format, similar to ZIP/.zip files)
$ curl https://cht.sh - general info about cht.sh
   

• • quic / http3 (19:40 - 19:50)
    • a newer hypertext transport protocol built on top of UDP
    • http ordinarily runs over tcp/ip, which does packet receipt verification (slower)
    • UDP is faster bc no ACK packets (TCP's ACKnowledge receipt of a packet packet)
    • hence UDP is less reliable than TCP, but clients can re-request a resource that doesn't verify
    • WebRTC is a related technology used to deliver audio & video streams with UDP packets

• cloudflare tunnels + funnels (tailscale) (19:50 - 20:00) (didn't discuss)

• ml question -- tokenization of domain-specific data, to convert tokens to scalars, with PCA a possible goal (Loren's suggestion is hdbscan) (didn't discuss further)

• lean4 -- via llm?

• Lean Game Server
  • • https://adam.math.hhu.de/

Outro

• Frank -- more about protocols
• more about middleboxes* (not middleware)
• great head of line blocking explanation
• great intro to lean4 in the nat number game
• scheduling -- os, and distributed system scheduling, job queue
• ssh-agent, woo! pointers on data thing I want to do -- perhaps hdbscan
• ssh-agent -- will use, using tailscale. wireguard
• ssh key, use
• more about quic
• distributed systems --
• head of line blocking -- catastrophic connection failure /
• quic, more about -- more about protocols over other protocolo
• learned about TCP/UDP/IP -- trying to learn more about middleware
• new to infra + backend. new to these decisions, tradeoffs. lots of tradeoffs. Learning the importance of cybersecurity + cryptography.
• head of line blocking
• more about protocols
• auth protocols -- OAuth
• more about protocols, want an llm framwork comparison

Questions, Discussion, or Coworking

• [Issue]

For next time

Readings & Exercises

• Readings
• Exercises

Join online

• Try it yourself!
  • Join libera.chat #nb-meetup-infra

https://www.noisebridge.net/wiki/Meetups/Infra