Sendit is a small program for sending large files over a network.

It includes a very small, basic HTTP 'server'. The server accepts connections
on a certain port, and offers to the user to upload a file if the correct page
is accessed. It then saves that file to the current working directory, and
exits. If the user accesses the wrong page, it replies with a 404.

Sendit is supposed to be used in conjunction with a web service to automate the
users and IP addresses:

1. Alice wants to send a file to Bob, but the file is too large to email. She
   also doesn't want to upload it on a public file server like Rapidshare and
   have Bob download it.
2. Alice connects to the sendit web service and enters hers and Bob's email
   addresses.
3. The web service generates a unique key for the transaction, and sends an
   email to Alice to verify she isn't a spammer, with a link to a certain page
   to validate the key.
4. When Alice validates the key, the service sends an email to Bob with a link
   to download the sendit program customized to only accept connections from
   Alice's IP, on a page equal to the unique key.
5. When Bob downloads the program, the service sends an email to Alice with a
   link to the correct page to access, e.g. if the unique key were
   1234567890ABCDEF and Bob's IP were 192.0.2.37. The link in Alice's email
   would be to http://192.0.2.37/1234567890ABCDEF
6. The web service deletes all information of the transaction. If something
   goes wrong (like Bob's dynamic IP changing, or, if his server only accepts
   connections from Alice's IP, her dynamic IP changing), Alice would have to
   restart at step 2.

Of course the sendit program itself doesn't have to be used with this web
service, but the service automates the generation of keys and the exchange of
IP addresses for users who don't know what those things are.