How to connect to a uTasker Web Server from the Internet

[BitCoder]

I am wondering how I can connect to a device that runs the uTasker Web Server from the Internet? I have define the IP as 192.168.0.90, the Submask as 255.255.255.0 and the Gateway as 192.168.0.1 witch is our default Gateway to the server.

Thanks
Tom

[mark]

Hi Tom

1) First of all you need to know the address of your router on the Internet (if you log in to it you will be able to find this somewhere - it is either a dynamic IP address (when you haven't rented a fixed on) or a fixed address (which your would probably already know since you pay extra for it).

2) The simplest method is to configure a DMZ (Demiliterized zone) on the address of your device, which will be 192.168.0.90. Most routers will support this. With this enabled in the router, all incoming traffic which doesn't match with active connections started from the internal side of the router, will be sent to that internal address. Your board will then receive all such traffic, irrespective of the port numbers involved.

3) A second method is to configure a virtual server in the router. For example on TCP port 80 to be routed to the internal address 192.168.0.90 on TCP port 80. This will allow your board to be connected to on port 80 (the web server port) from the Internet on the router's external IP address (see 1). "http://xxx.yyy.zzz.aaa".

Note that if you don't have a fixed IP address you may find that the router's external IP address changes now and again - however for first tests it should be OK (depending on the provider and technology used it may change within a few hours or it may even stay fairly stable for longer periods of weeks or months). For users without a fixed IP address, Dynamic DNS (DynDNS) is a technique that can be used to allow a URL (eg. www.abc.org) to be routed to this IP address, whereby the Dynamic DNS server will allow the IP address to be tracked - this however requires some DynDNS support which may be possible in the router (?).

Regards

Mark

[BitCoder]

Hi Mark

Thanks for the explanation Mark.
What happened in case of the following scenario?
A LAN (same Local Network) has several devices that run uTasker. Each uTasker runs its own web server. In this case the first method (2) I guess will fail because it is not possible to assign more then one IP to a DMZ device. Is this assumption correct?
The second method (3) will work but I have to give each device a separate port in the router. To access such a device from the Internet I must enter an URL like this “http://xxx.yyy.aaa:n where n is the assigned port number. Is this assumption correct?

Thanks
Tom

[mark]

Hi Tom

Yes, your assumptions are correct.

The DMZ case is a 'catch-all' and is useful for a single, uncomplicated server solution.

As soon as you have more servers each needs its own internal IP address and virtual servers in the router can route (for example) http://xxx.yyy.zzz.aaa:n,
http://xxx.yyy.zzz.aaa:(n + 1), http://xxx.yyy.zzz.aaa:(n + 2), to internal 192.168.0.5:80, 192.168.0.6:80, 192.168.0.7:80.

Note however that it is sometimes a problem to use web servers on TCP port numbers other than 80. This is because firewalls (at remote locations) may be set up to only allow port 80 to work. Some companies forbid web server operqation on ports other than 80 (by firewall configuration).

Often port :8080 is used as a second web server port to port 80.

Also take a look at the IPv6 document: http://www.utasker.com/docs/uTasker/uTaskerIPV6.PDF
This explains how it is possible to allow many internal devices to share an IPv6 access point but, using DMZ, each have its own IPv6 web server address (all on port 80).

Regards

Mark