Periodic updating of DynDNS


Hi All,

Is it possible that after you attach to GPRS and then obtain your assigned IP address from the APN, that this address can be re-assigned even if you never lose the APN connection?

(Assume that I have a public, dynamic SIM account).

The reason for my question is - on power-up after obtaining GPRS then APN attachment, I update DynDNS (if neccessary i.e. if there has been a change to the assigned IP address from the previous time). Is it neccessary to check the assigned IP address once in a while even though connection to the APN is not lost? If so, is there a recommended ‘once in a while’ check time?



Someone must have had experience with this? Davidc maybe??


There isn’t actually any way to know that you’ve lost the APN connection - other than by attempting to use it.

So you could kill 2 birds with one stone, and use the DynDNS update as your “heartbeat” to check that the link is still alive… 8)

IF you’ve got that, I’d assume that you would have had to specifically apply for it - and there should be a support desk who could answer the question…


Awneil, thanks for the hearbeat idea with updating DynDNS.

I will contact the SIM account support re my original question.


For further info, try a search on “heartbeat”; eg,



You have to watch that you don’t update your DynDNS account too often (when the IP hasn’t changed) or they (DynDNS) will ban the IP. Their rules are on their website…

I would look at maybe storing the IP address your module recieves during the WIP_BEARER_CONNECTED event and check periodically (using wip_bearerGetOpts) to see if it has changed.

One of my gripes with WIP is that it doesn’t let you know when the bearer has gone away - except when you attempt to do a connection and you get a timeout on the WIP_WRITE. The only way I have found to test when the ‘network’ goes away is to register for the ADL GPRS events using adl_gprsSubscribe(). In particular, I’m monitoring the ADL_GPRS_EVENT_ME_UNREG and ADL_GPRS_EVENT_ME_ATTACH events to monitor the state of the network connection.

Hope this helps.

ciao, Dave