- In ssh, knowing how to port tunnel with `-L` or `-D` (and occasionally `-R`) is useful, e.g. to access web sites from a remote server.
- It can be useful to make a few optimizations to your ssh configuration; for example, this `~/.ssh/config` contains settings to avoid dropped connections in certain network environments, and use compression (which is helpful with scp over low-bandwidth connections):
- It can be useful to make a few optimizations to your ssh configuration; for example, this `~/.ssh/config` contains settings to avoid dropped connections in certain network environments, use compression (which is helpful with scp over low-bandwidth connections), and multiplex channels to the same server with a local control file:
```
TCPKeepAlive=yes
ServerAliveInterval=15
ServerAliveCountMax=6
Compression=yes
```
- To lower network overhead, this `~/.ssh/config` contains settings to multiplex channels to the same server with a local control file: