Implementing DynDNS when acting as a server

[awneil]

@awneil

we’re talking here about the specific case where the OP has paid-up for a Public (though not static) IP address.

@davidc

This wasn’t clear from the OP’s postings.

Maybe not.

I was taking this (with my emphasis):

@mike_rink

I believe it is true that in order to get the public IP address assigned to you from an APN (assuming you have a public, dynamic IP account)

to mean that he did, in fact, have a “public, dynamic IP account”

Maybe I was reading too much into that?

@davidc

In fact, they indicated that their module was getting a 10.x.x.x address

what he actually said was:

@mike_rink

If you use wip_bearerGetOpts and WIP_BOPT_IP_ADDR, the address given is a private address, i.e. from the private side of the APN. In my case it was 10.xxx.xxx.xxx.

and, as I said, I would expect this to be like doing ipconfig on a Windows PC - so it would only give you the “local” address in the “private” side of the network - not the Public address.

eg, if I do ipconfig on this PC, I get 192.168.xxx.yyy - which is the private address in my local network;
if I do whatismyip.com I get 86.147.aaa.bbb - which is the Public address of my broadband modem/router

I’d assumed that wip_bearerGetOpts would work like ipconfig to give just the “local” private address within the GPRS network, and something like whatismyip.com would be needed to find the Public address.

Note that whatismyip.com et al will always give a public address - but that does not mean that you can use that address for incoming connections to your device! That’s the privilege for which you have to pay extra!
(you can try this with the WIP sample that does an HTTP GET…)

[Madouc]

@awneil

@Madouc

We’re opening a channel to our server, and keeping it alive by sending a packet at least every 14 minutes.
that way we keep an open channel from i [/i]the server -trough the nat-firewall of our isp- to our clients.

Don’t you mean, "keep an open channel to the server" there?

It’s not directional once the channel is opened.

1. The client sets up a tcp connection to the server.
2. The server (custom build tcp server) pings the client (ie send it a byte) every 14 minutes, the client responds with a byte.
3. now we have a tcp channel on which we can send events from the client to the server, but also send events from the server to the client.

@awneil

thus we can push i [/i]events to them.

Don’t you mean that the clients can pull events?

nope, i do mean push events.

i still can’t create a new tcp connection from the server to the client, so we have to keep the all open, but as long as we don’t have more than +± 64000 units that shouldn’t be a problem. (else we can always get another server-ip )

[victorjd]

@awneil

@victorjd

On my experience - it’s not true. If your account really support public address, wip_bearerGetOpts() returns exactly that address.

Is that with a Static Public address?

No, dinamic. Additional paid service named “Real IP” give your modem public IP address on every GPRS connect.

“Whatismyip” services usage is for situation with your “private” server behind “public” router/firewall

Yes - but isn’t that how (at least some) GPRS “Public IP” services work…?
Especially if it’s not a Static Public address?

Hmmm. No…? What benefit from such an address? At least i want some port forward.

I write a little program router for PC behind firewall/proxy. It use list of http “what ip” servers and announce detected IP on FTP. Modems (without any “real” ip) also check FTP for server address and establish outgoing connection to router. Of cause, router listen port must be forwarded through proxy.