grvgr

WireGuard Site-to-Site

Accessing a subnet that is behind a WireGuard client using a site-to-site setup

Problem Summary

We want to access a local subnet remotely, but it is behind a NAT firewall and we can't setup port forwarding. Outgoing connections work, but all incoming connections get DROPPED by the ISP's routing policy.

Solution Summary

grvgr

Resources: 
http://code.google.com/p/dragonfly
http://sourceforge.net/projects/natlink/
http://tech.groups.yahoo.com/group/VoiceCoder/

Inspirations:
http://emacs-vr-mode.sourceforge.net/
http://sourceforge.net/projects/voicecode/
and especially http://shorttalk-emacs.sourceforge.net/ShortTalk/index.html from which I've stolen a few key ideas and utterances.

grvgr

# Reliable persistent SSH-Tunnel via systemd (not autossh)
# https://gist.github.com/guettli/31242c61f00e365bbf5ed08d09cdc006#file-ssh-tunnel-service

[Unit]
Description=Tunnel for %i
After=network.target

[Service]
User=tunnel
ExecStart=/usr/bin/ssh -o "ExitOnForwardFailure yes" -o "ServerAliveInterval 60" -N tunnel@%i

grvgr

Keybase proof

I hereby claim:

• I am grvgr on github.
• I am grvgr (https://keybase.io/grvgr) on keybase.
• I have a public key ASDz3AzFY99B_-8SNsjAu-seqK6mF7bUqRG1GHNWKr3d3go

To claim this, I am signing this object:

grvgr

/* compile: gcc prime.c -o prime -fopenmp */

#include <stdio.h>
#include <time.h>
#include <omp.h>

int main(int argc, char *argv[]) {
  double start, end, runTime;
  int num = 1, primes = 0, limit;

grvgr

Latest links are always available at:
https://www.privateinternetaccess.com/pages/client-support
https://www.privateinternetaccess.com/pages/downloads

In case you're unable to access the PIA website:

option 1:
macOS:   https://installers.privateinternetaccess.com/download/pia-latest-mac.dmg
Windows: https://installers.privateinternetaccess.com/download/pia-latest-win.exe
Linux:   https://installers.privateinternetaccess.com/download/pia-latest-linux.tar.gz

grvgr

OS X Preferences

---

most of these require logout/restart to take effect

# Enable character repeat on keydown
defaults write -g ApplePressAndHoldEnabled -bool false

# Set a shorter Delay until key repeat

grvgr

Latency numbers every programmer should know

L1 cache reference ......................... 0.5 ns
Branch mispredict ............................ 5 ns
L2 cache reference ........................... 7 ns
Mutex lock/unlock ........................... 25 ns
Main memory reference ...................... 100 ns             
Compress 1K bytes with Zippy ............. 3,000 ns  =   3 µs
Send 2K bytes over 1 Gbps network ....... 20,000 ns  =  20 µs
SSD random read ........................ 150,000 ns  = 150 µs

Read 1 MB sequentially from memory ..... 250,000 ns = 250 µs

grvgr

#!/bin/bash
# -*- mode: shell-script -*-

# requires: brew install brightness

execPath=/usr/local/bin/brightness
brightApps=(iTerm iTerm2 Emacs)
ignoreApps=(Alfred)
logFile=/tmp/auto.brightness.log
logEnable=false

grvgr

Oops! I accidentally deleted a local git branch, and I haven't pushed it to a remote server yet. The branch has several important commits, and it hasn't been merged with any other branches yet. How do I find the missing branch?

1. Create a list of all dangling or unreachable commits.

$ git fsck --full --no-reflogs --unreachable --lost-found
unreachable tree 4a407b1b09e0d8a16be70aa1547332432a698e18
unreachable tree 5040d8cf08c78119e66b9a3f8c4b61a240229259
unreachable tree 60c0ce61b040f5e604850f747f525e88043dae12
unreachable tree f080522d06b9853a2f18eeeb898724da4af7aed9