How can I submit a large file to a colleague without flooding his mailbox?

First of all: Don’t use e-mail. I suggest three options:

The easy way

Go to https://wetransfer.com, add your files, provide the recipient’s and your e-mail address, write a short text message, and click Send.

An app to facilitate this is available for macOS and iOS, too. Works for free with files up to 2 GB per transfer.

The confidential way

Use the Cryptshare service of the Max Planck Society.

The traditional way

Upload the file(s) to your personal web space and send the link via e-mail or other means. Works roughly like this:

  1. Mount your network home directory: Go to Finder, choose Go->Connect to Server … (or press Command-K) and enter the server address smb://flsrv._smb._tcp.cpfs.mpg.de. After authentication (not necessary when logged in on an Institute’s Macintosh) you will be presented with a list of network volumes. Choose either homes0 or homes1, depending on whether your username starts with a letter of the lower half of the Latin alphabet or the upper. Click OK and double-click the folder with your username in the resulting Finder window.

  2. If it is not already there, create a directory public_html inside your home directory.

  3. Copy the file you wish to share into the newly created directory. Let’s assume it is called RecentResults.tar.gz.

  4. Send an e-mail to the intended recipient containing the URL of the file, which is of the form http://www.cpfs.mpg.de/~user/RecentResults.tar.gz. (Replace user with your username.) By clicking onto that link, the recipient of the e-mail can download the file automatically and directly to disk.