Add dynamic-ssh-forwarding.md

networking/dynamic-ssh-forwarding.md

@@ -0,0 +1,36 @@
+## Set up port forwarding
+
+1. Set up port forwarding
+   ```bash
+   $ ssh -D 8080 -N ubuntu@mercurial-manfifold.eu
+   ```
+2. Try out connection
+   ```bash
+   $ curl --socks5 127.0.0.1:8080 http://example.com
+   ```
+
+## Set system-wide proxy configuration
+
+1. Create `/etc/profile.d/proxy.sh` with the following content:
+   ```bash
+   #!/bin/bash
+
+   if [ -f "/etc/proxy-enabled" ]; then
+       export http_proxy="127.0.0.1:8080"
+       export https_proxy="127.0.0.1:8080"
+       export ftp_proxy="127.0.0.1:8080"
+       export HTTP_PROXY="127.0.0.1:8080"
+       export HTTPS_PROXY="127.0.0.1:8080"
+       export FTP_PROXY="127.0.0.1:8080"
+       export no_proxy="localhost,127.0.0.1,::1"
+       export NO_PROXY="localhost,127.0.0.1,::1"
+   fi
+   ```
+2. Add the following to `.zshrc`:
+   ```bash
+   alias proxy-on='sudo touch /etc/proxy-enabled'
+   alias proxy-off='sudo rm -f /etc/proxy-enabled'
+   ```
+
+Note that enabling or disabling the proxy only takes effect after logging out
+and back in, as that is when `/etc/profile.d/proxy.sh` is sourced.