MailList on 7 Jan 2012 07:41:44 -0800

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[PLUG] Need Help with TCPDump

I bought one of those goofy internet clocks ( and 
despite a few problems, have been able to get my messages sent to it via the 
company's web page or eMail.

However, being one who will never leave anything working alone (I have an 
unsatisfiable desire to "improve" things! <grin>), I want to hack this little 
bad boy.

I have not found anything published on the protocol for the clock, so I 
thought I'd just sniff the network stream and  figure out what it's doing.  I 
can tell from my DHCP server that it's getting a lease at  I 
therefore tried this command on my firewall.

tcpdump -i eth1 host

I then used the web page to successfully send a message to the clock.

Oddly, I'm not getting anything recorded by tcpdump.  If I drop the host 
portion and just grab everything, the address of the clock never shows up.

Could somebody suggest what I'm doing wrong, or some other approach that might 
let me figure out how this thing communicates?

Ideally, I want to be able to directly send messages to the clock, without 
using the company's web service.

Casey Bralla
Chief Nerd in Residence
The NerdWorld Organization
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