🚀 go-pugleaf

In article <3768a6f3.3737861@news.demon.co.uk>, Jim M wrote:
> Thought as much.  Going to dig around  the VC6 samples for a telnet
> example.  It seems that establishing a connection to everything on the
> internet can be done by establishing a telnet session, pointed to a
> particular port.  

The telnet program provided with Windows can be used as a useful way to 
exercise a mail or news server "by hand" (i.e. you type in the 
instructions, and see the responses).

The actual telnet protocol is quite complex, but you don't need to use 
telnet protocol in your program. You just open a socket on a port, and 
then treat it like an input/output stream - write data or text to it, and 
read data or text from it. Actually, neither mail nor news involves 
anything except plain text.

The situation is complicated in a Windows environment because you have to 
process the I/O through the socket asynchronously while also running your 
Windows message loop. The Winsock interface provides asynchronous I/O 
using Windows messages to indicate request completion/error. A simpler 
alternative might be to run the socket I/O in a separate thread for each 
server connection.

> I suppose I've got be careful with experimenting, due to a recent
> thread about portscanners in d.service.  Make sure my variables don't
> get corrupted and all that...

Provided you have all the security patches for your operating system, and 
that you take similar precautions as you would reading a data file from 
an unknown source, you should be OK. You should have the security patches 
anyway, if you are ever connecting to the Internet.

-- 
Nikki Locke, Trumphurst Ltd.      PC & Unix consultancy & programming
nikki@trmphrst.demon.co.uk            http://www.trumphurst.com/