How to discover devices on network

[stacy]

I am developing an application that must look out over TCP on an
ethernet connection to
locate our proprietary devices. The Web application and the devices
are communicating over ethernet with TCP using known IP addresses at
present. We would like to design a method to discover devices in the
system without knowing their IP addresses. Is there a recommended
protocol for this type of problem or do most develop their own
protocol? Any suggestions on how to do this would be appreciated.

Regards, Stacy

[Mike Lowery]

You have two choices: either probe for IP addresses on your network or sniff the
traffic to discover them. In the case of the latter, you might try using
WinPcap (http://www.winpcap.org/).

<st***@sensorswitch.comwrote in message
news:11**********************@n13g2000cwa.googlegr oups.com...

>I am developing an application that must look out over TCP on an
ethernet connection to
locate our proprietary devices. The Web application and the devices
are communicating over ethernet with TCP using known IP addresses at
present. We would like to design a method to discover devices in the
system without knowing their IP addresses. Is there a recommended
protocol for this type of problem or do most develop their own
protocol? Any suggestions on how to do this would be appreciated.

Regards, Stacy

[stacy]

Hi,

Thanks for the suggestions, we can modify the devices, we are
developing them ourselves. Are you suggesting the I send a message out
to the subnet broadcast address IE: xxx.xxx.xxx.255? I thought that
UDP was not a guaranteed protocol, in which case, how can I be certain
that all devices do indeed receive and reply to the message?

Thanks again,
Stacy
Vadym Stetsyak wrote:

Hello, st***@sensorswitch.com!

sI am developing an application that must look out over TCP on an
sethernet connection to
slocate our proprietary devices. The Web application and the devices
sare communicating over ethernet with TCP using known IP addresses at
spresent. We would like to design a method to discover devices in the
ssystem without knowing their IP addresses. Is there a recommended
sprotocol for this type of problem or do most develop their own
sprotocol? Any suggestions on how to do this would be appreciated.

IIRC there is no such protocol, but there are number of approaches how to handle the problem.

If you can modify devices ( I mean write additional logic on them ) and web app with devices are in the LAN,
then UDP broadcast/multicast can be used.
Devices will respond to that broadcast.

--
Regards, Vadym Stetsyak
www: http://vadmyst.blogspot.com

[r norman]

On 8 Aug 2006 09:11:05 -0700, "st***@sensorswitch.com"
<st***@sensorswitch.comwrote:

>Hi,

Thanks for the suggestions, we can modify the devices, we are
developing them ourselves. Are you suggesting the I send a message out
to the subnet broadcast address IE: xxx.xxx.xxx.255? I thought that
UDP was not a guaranteed protocol, in which case, how can I be certain
that all devices do indeed receive and reply to the message?

'Not guaranteed' does not mean totally unreliable. Very few
broadcasts fail. Still, all you do is broadcast periodically, once a
minute, or once every ten seconds. You will virtually never miss even
one. Missing three or four in a row is essentially impossible!

Of course, some network administrators take a dim view of broadcasts
and don't let them through the switches so make sure that those
broadcasts on that specific port address are acceptable.