How NetXfer Works

  NetXfer is a multi platform software designed to transfer your files point to point, without landing on a server, as quickly and securely as possible.  This page is an overview of how NetXfer works, and why it is the most secure choice for your sensitive information.

How It Works

  The core of NetXfer is a 256 bit AES encryption engine, local to the software, that encrypts every packet of your file before it leaves your computer.  After encryption, the packets of data from your file are sent via UDP directly from your computer to the receiving computer via a direct socket connection.  As this transfer will require some information to set up, NetXfer uses a simple, text based ‘Transfer Packet’ of information to let the receiver know how to get the file, and to ensure only the receiver can download it.

  There are two modes NetXfer will run in:  Direct Network and Rendezvous.

Direct Network

  If the sender and receiver can route directly to one another, setting up a transfer is as simple as sending the transfer packet text through a secure channel (secure chat, webrtc, any other secure method) from the server to the receiver.  When the receiver gets the packet, it will know the sender’s IP address, the file’s id and size, the encryption key and the password.  It will then contact the sender, validate the transfer packet and receive the file.


  If one or both of the computers are behind a firewall/nat/home/corporate network, they will not be able to simply connect.  Each of them will need more information, with which they can make a direct, encrypted connection to transfer the file.  There are two ways to transfer the required information: Automatic, where a minimum amount of text from the transfer packet is temporarily saved on a server via HTTPS encrypted protocol or Manual, where the information is sent back from the receiver to the sender.  The rendezvous process proceeds like this:

  1. The sender automatically sends some of the transfer packet information to  (or your own server if using the corporate version).  This information is limited to:
  1. Computer’s local and remote IP addresses and port
  2. File ID and size
  3. Unique transaction ID
  1. The sender then sends the receiver the normal transfer packet via secure link
  2. The receiver uses the information in the transfer packet to validate with and add this information:
  1. Its local and remote IP address, port, and a flags value
  1. The sender validates against, retrieves the receiver’s information, and at that point a secure, direct connection can be established.
  2. For advanced users, the server can also be avoided completely by having the receiver send a receipt transport packet via secure channel instead.

How It Compares

  There are many services for sending and receiving files available, but NetXfer is one of the few that does not store your file on a server at any point.  Having your files on someone else’s server is always a risk, and relies on their security, their cloud provider’s security and their continued existence.  While you can set up various methods of serving files from within your environment, most of them will require a server somewhere to hold the file, and that will leave it vulnerable to being read by the wrong person or even forgotten and lost when that server is inevitably upgraded.  There are many workflows that file servers make sense for, but for the most secure transfers, there is NetXfer.

A Workflow Example

  NetXfer is an ideal way to move digital rushes from the field to your post facility.  A NeXfer instance on the local DIT machine can send all of the individual files to a server within the post facility directly, encrypted from end to end.  Because NetXfer uses UPD, the transfers will saturate your connection, and with NetXfer’s automatic packet recovery system, even terrible internet connections will be used to the fullest bandwidth, and reliably get every file from field to office.  Optional automatic MD5 generation and checking guarantees what you captured in the field ends up at your editor’s desk.

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