[ILUG] Network programming question....

[Justin MacCarthy]

Nick the code from nmap . very fast scanning tool 

http://www.insecure.org/nmap/nmap_doc.html

Justin 

> -----Original Message-----
> From: ilug-admin at linux.ie [mailto:ilug-admin at linux.ie]On Behalf Of
> Stephen Shirley
> Sent: Tuesday, February 05, 2002 2:06 PM
> To: ilug at linux.ie
> Subject: [ILUG] Network programming question....
> 
> 
> Mornin' all,
> 	Here's the problem. I had a linux box (A), and a sun box (B). They
> 	are both connected to a 100mb switched private lan. They are the
> 	only boxen on this network. I have complete control over A, but none
> 	over B. I need to be able to write a program to run on A that will
> 	detect as fast as possible if B is up or down. Calling ping or any
> 	other external programs is out of the question - too much overhead.
> 	This might have to be done many times a second. My initial idea was
> 	to open a tcp connection to a port i know is closed on B, thereby
> 	getting a REJECT, and confirming it's up. This solution takes on
> 	average 509 usecs to say yay, and times out after 500 msecs
> 	(configurable) to say nay. 
> 
> 	Now it's been suggested that I try some facny tcp half-connect
> 	modes, or maybe even arp. However, networks aren't my speciality. I
> 	was wondering if anyone had any suggestions/comments.
> 
> TIA,
> Steve
> P.s. I know that this is not strictly a linux question, but this is a
> linux _users_ list, and i'm doing this using linux.
> -- 
> "My mom had Windows at work and it hurt her eyes real bad"
> 
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