Scanning machines on a network

[Dar Scott]

On Tuesday, March 12, 2002, at 04:03 PM, Sarah Reichelt wrote:
> There has been an alternative approach suggested:
>
>     put hostnametoaddress(hostName()) into myIP
>
> but I found this didn't give any result as my hostName() is always 
> empty.

My system does the same.

> I too worried about the etiquette of connecting to an external 
> server but I
> don't do it often and I spread the queries around several sites.

I think I have found a way that works on OS X.  I'm not sure if it 
is a good general way.

I have a test card that sends a UDP datagram and receives a UDP 
datagram.  I am using this to help me learn about Revolution.  I 
receive with "accept" and get the data on the second message to the 
specified message handler.  That message includes the IP address of 
the sender.  I send the datagram with open-write-close.

Here are four of the ways I can send to myself:

Destination IP Address                  IP Address given to handler
----------------------                  ---------------------------
127.0.0.1                               127.0.0.1
255.255.255.255                         <my ip>
0.0.0.0                                 <my ip>
<my ip>                                 <my ip>

Where <my ip> means the IP address of this computer.  (127.0.0.2 
does not work.)

The third method could be used to get the local IP address.  (The 
second method might work on more platforms, but several apps on the 
LAN doing this might interfere with each other unless some extra 
code is added.)

I'm not saying this is a good method; it is another.

Dar Scott
Revolution Newbie