CODEWITHSUNDEEP
filetcpudpiptransfer
Ruben
Ruben

Reputation: 524

Reliable way to send file over internet

First of all: I'm not absolutely certain that this is the right place to ask, but I think the question fits here better then on superuser or serverfault, since it is a question from a programmer's perspective: I figured more programmers might have had the same question (although I couldn't find this specific question!).

I would like to have a feature in my program which allows users to send files to a 'friend'. You can find friends via an username: this all goes via a server which can provide the IP-adress of a friend. I wanted to use a tcp connection to send the file. This becomes difficult, however, when one (or both) of the parties is behind a NAT. What is the best way to solve this? I heard that it's possible to send stuff via a server, but I'd rather send everything directly, to prevent server overhead.

I heard about a technique called hole punching, but also that it's pretty complex to implement and not 100% reliable. I could use UDP and implement some scheme to improve the reliability, but this seems a bit complex to me. I know skype, bittorrent and a whole lot of other programs do similiar things (but I don't know about the specifics, which protocol they use, if they use hole punching etc.).

I looked into FTP a bit, until I realised that this is just a protocol using TCP, so I should use TCP hole punching in order to let this work... Anyway, I hope someone can give me some advice on this :)

Upvotes: 4

Views: 228

Answers (1)

Davide Berra
Davide Berra

Reputation: 6568

If you don't want to make data pass through a server, I'm not aware of other methods other than TCP Hole Punching or simple Port forwarding of a previously choosen port.

Upvotes: 2

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