UDPXfer - UDP file transfers based on .NET

News

2005-11-07: Initial public release, v1.0.2132.3850

About

UDPXfer is a utility designed to transfer single files to another host over UDP, supporting both active and passive connections. For most file transfers, TCP usually provides the highest speed and reliability. However, on high packetloss lines (20%+), the lost TCP segments cause excessively high delays between retransmits, which only get progressively worse as more packets are dropped. This results in transfers stalling and timing out.

To overcome the problem of TCP and high packetloss, UDPXfer constantly transmits random segments of the file to the receiver. The receiver then sends acknowledgements of which segments it has received to the sender, which will in turn stop transmitting those segments. The process continues until all segments are acknowledged. There are no timeouts or other such errors - the process will continue indefinitely until the receiver acknowledges all segments or one side aborts the process. This provides a way to reliably transfer a file over a very poor line at reasonable speeds. An SHA-1 hash is also added to each segment to ensure error-free delivery.

Usage

UDPXfer requires Microsoft .NET 1.1 to function. Simply run the .exe in either send/receive mode, fill in the required settings and hit start. UDPXfer runs over port UDP/62999 so be sure to adjust your router/firewall ACLs as needed. To run the sender in passive mode, enter the word 'passive' into the destination box. Each segment is approximately 1KiB in size; the sender can adjust the packet rate to match their line speed for best results. Please note that use of UDPXfer will result in some bandwidth waste due to constant retransmissions - UDPXfer is only recommended to send or receive files on high packetloss connections.

Download

WARNING: UDPXfer is designed for use over trusted networks. This program was made as a quick fix for myself in order to be able to send files over UDP and thus may contain remotely exploitable bugs if connecting to an untrusted host. This program is provided AS-IS with no warranty.

UDPXfer-v1.zip (13 KiB). Version 1.0.2132.3850.