Search for IPs?

[Dar Scott]

On Wednesday, March 13, 2002, at 02:48 PM, Josh Dye wrote:

>     I was wondering if there is any way that Rev could do a search 
> for open IP Addresses on a network. Like, have it search for 
> 192.168.0.???. And where the ??? is, it would search every IP from 
> 1 to 255 and see if any computer is using that IP address. And, if 
> it is using an IP, have it put the results in a field. Is there 
> any way or something similar to do this?
 
(You probably want 1 to 254; if your subnet mask is 255.255.255.0, 
then 192.168.0.255 will be a broadcast address.)

The short answer is NO.  The longer answer is maybe, but it will be 
awkward.

A computer with a firewall might be setup so that it does not 
respond to outside probing.

The most common method is to ping.  I don't know of any Revolution 
way to do that.  It is outside of TCP and UDP.

You might be able to set up some rule for all computers.  Say, 
every computer must supply the trivial TCP/IP services such as 
ECHO.  You can then try to TCP to the ECHO port on every address.

If Revolution error handling can indicate certain kinds of errors, 
it might be possible to learn of a computer from rejected TCP 
connections or rejected UDP datagrams.  I doubt this.

There might be some other way, but none come to mind.

If you are thinking of using this list of IP addresses for polling, 
I suggest you invert the notion if possible and have each program 
you want to poll broadcast its presence.  Or poll all addresses.

Dar Scott