System.Net.Sockets and Console applications (VB.NET)

[darkforcesjedi]

Ok...here's what I'm trying to do...

 

I'm trying to write a SOCKS4-type proxy with a console interface to display status information. (e.g. I would type connections at the prompt and get a list of connected clients). I've never written a network application before, but the logic seems simple enough. I found some sample code that listens for a TCP connection. The first packet I get from the client is to negotiate a connection. I get the target IP address and port number from the client.

 

I don't know what to do next. I presume I need to open a connection with the server. I tried this (I used reverse DNS to get the hostname from the IP address, which is probably bad because some reverse DNS lookups will probably fail):

 

'this always times out

target = New System.Net.Sockets.TcpClient(EndHost, EndPort)

 

 

I searched google and planet source code supposedly has a sample proxy server in VB.NET, but I can't get to the site.

[archer_coal]

re networking

 

I found a nice NETSTAT example for networking in VB.NET that may shed some light on the subject for you.

 

http://www.codeproject.com/vb/net/netstat.asp

 

and here is a console http proxy source i found as well

 

http://www.planet-source-code.com/vb/scripts/ShowCode.asp?txtCodeId=1145&lngWId=10

 

Hope they help

[darkforcesjedi]

I found the same proxy example but I couldn't access the site.

[archer_coal]

RE

 

PM me with your EMAIL address and ill email the source to you.

[darkforcesjedi]

Ok, thanks!

[darkforcesjedi]

Why doesnt this work?

 

IPSocket = New Socket(Net.Sockets.AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp)

Dim IPHost As IPHostEntry = Dns.GetHostByAddress("192.168.0.1")

Dim sEndPoint As New IPEndPoint(IPHost.AddressList(0).Address, EndPort)

IPSocket.Connect(sEndPoint)

 

 

Dns.GetHostByAddress crashes...

[PlausiblyDamp]

When you say Dns.GetHostByAddress crashes - what exception do you get?

 

Also if you drop to a command prompt and type

ping -a 192.168.0.1

what results do you get?

[darkforcesjedi]

It seems to be failing because the IP address has no DNS entry. I can ping the IP Address, but nslookup [ip address] fails