TRAMP

Emacs' TRAMP feature (Transparent Remote file Access, Multiple Protocol) is an extremely powerful tool for editing files that exist on remote systems, or require access using a different user account from your main Emacs session, or both.

Some of the things that TRAMP can do include:

• Editing files on a remote development server over SSH (e.g. /ssh:remote-user@remote.box:/path/to/my/file)
• Editing files on your local machine as root via sudo (e.g. /sudo::/etc/some/config/file)
• Editing files on a remote server as root via sudo over an SSH connection from another remote machine that exists within a DMZ (requires a little bit of configuration)

TRAMP is included with Emacs and described in the manual.