C# Proxy using Sockets, how should I do this?

Question

I'm writing a proxy using .NET and C#. I haven't done much Socket programming, and I am not sure the best way to go about it. What would be the best way to implement this? Should I use Synchronous Sockets, Asynchronous sockets? Please help!

It must...

Accept Connections from the client on two different ports, and be able to receive data on both ports at the same time.
Connect to the server on two different ports, and be able to send data on both ports as the same time.
Immediately connect to the server and start forwarding packets as soon as a client connection is made.
Forward packets in the same order they were received.
Be as low latency as possible.
I don't need the ability for multiple clients to connect to the proxy, but it would be a nice feature if its easy to implement.

Client --------- Proxy ------- Server
---|-----------------|----------------|
Port <--------> Port <-------> Port
Port <--------> Port <-------> Port

Can you limit your code to running on Windows Server 2008? – James Westgate Apr 12 '10 at 09:31 — James Westgate, Apr 12 '10 at 09:31
No, it has to at least run on Windows 7. – Kin Apr 12 '10 at 10:20 — Kin, Apr 12 '10 at 10:20

score 3 · Accepted Answer · answered Apr 12 '10 at 13:43

3

I've tinkered with this source code before. It was done well, recommended.

answered Apr 12 '10 at 13:43

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This is quite easy to follow, thanks! It's not compiling with 3.5 though, and it is quite old. Is there anything specific I should avoid doing (outdated, or better way) that is used in this? – Kin Apr 12 '10 at 15:48
1

@kin - compile issues are easily fixed by compiling as .NET 1.1 (not tried) or by casting the expression inside the offending Math.Floor as double. – Frederik Aug 07 '14 at 21:12
Address compiler issue: Use BitConverter.ToInt64(IP.GetAddressBytes(), 0) vs IP.Address. – Benj Sanders Sep 15 '15 at 23:53

score 1 · Answer 2 · answered Aug 31 '11 at 23:57

Please check out PortFusion! It is a complete, actively-used and -developed distributed reverse proxy solution for all TCP-based traffic. It is written for .NET 4.0 and comes with full source code.

I have tested ReceiveAsync and SendAsync methods introduced in .NET 3.5 but have not found them to reach as high a throughput as is possible with synchronous ones - Async ones should scale better in case of a great number of concurrent clients though.

Maximum throughput for a controlled number clients: use synchronous methods Reaching maximum number of concurrent connections: async

C# Proxy using Sockets, how should I do this?

2 Answers2

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