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µTasker general / Finding device with DHCP IP address
« on: June 27, 2009, 04:07:15 AM »
Hi, all.
Imagine that you send a uTasker device -- e.g., an intelligent coffee maker that has a web server on port 4388 -- to your friend to install in his house. Your friend knows almost nothing about networks, but someone has already set up an Ethernet network for him, so all he has to do is plug in the coffee pot. He would like to see the coffee pot's web page on his PC (via the LAN), and you'd like to see the web page on your PC (via the Internet).
What I don't understand:
1) how will your friend know what IP address was assigned to the coffee pot by his DHCP server?
2) how will you convince his router to accept traffic from you for port 4388 and forward it to the coffee pot? I.e., how do you open port 4388 through the router's NAT?
3) Number 2 comes into play only if you already know your friend's public IP address, which is most likely one that is assigned dynamically by his ISP and subject to change. There are solutions for this, see e.g., <http://www.dyndns.com/>. Some routers have a built-in update client -- the module that sends "here-I-am" to the dynamic DNS service at appropriate intervals -- but not all do. Is there uTasker code for an update client?
Given the push to attach everything in the world to the Internet, this problem must have been addressed somewhere, but I haven't seen where. I'd appreciate any hints.
Thanks,
Richard
Imagine that you send a uTasker device -- e.g., an intelligent coffee maker that has a web server on port 4388 -- to your friend to install in his house. Your friend knows almost nothing about networks, but someone has already set up an Ethernet network for him, so all he has to do is plug in the coffee pot. He would like to see the coffee pot's web page on his PC (via the LAN), and you'd like to see the web page on your PC (via the Internet).
What I don't understand:
1) how will your friend know what IP address was assigned to the coffee pot by his DHCP server?
2) how will you convince his router to accept traffic from you for port 4388 and forward it to the coffee pot? I.e., how do you open port 4388 through the router's NAT?
3) Number 2 comes into play only if you already know your friend's public IP address, which is most likely one that is assigned dynamically by his ISP and subject to change. There are solutions for this, see e.g., <http://www.dyndns.com/>. Some routers have a built-in update client -- the module that sends "here-I-am" to the dynamic DNS service at appropriate intervals -- but not all do. Is there uTasker code for an update client?
Given the push to attach everything in the world to the Internet, this problem must have been addressed somewhere, but I haven't seen where. I'd appreciate any hints.
Thanks,
Richard