# Periodic updating of DynDNS **URL:** \ **Category:** Open AT\ **Created:** [May 25, 2010, 9:37pm UTC](https://forum.sierrawireless.com/t/periodic-updating-of-dyndns/4443 "2010-05-25T21:37:33Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![mike\_rink](https://avatars.discourse-cdn.com/v4/letter/m/cab0a1/32.png) [@mike\_rink](https://forum.sierrawireless.com/u/mike_rink)\ **Post date:** [May 25, 2010, 9:37pm UTC](https://forum.sierrawireless.com/t/periodic-updating-of-dyndns/4443/1 "2010-05-25T21:37:33Z")
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? Thanks. ---
**Author:** ![mike\_rink](https://avatars.discourse-cdn.com/v4/letter/m/cab0a1/32.png) [@mike\_rink](https://forum.sierrawireless.com/u/mike_rink)\ **Post date:** [May 27, 2010, 4:22pm UTC](https://forum.sierrawireless.com/t/periodic-updating-of-dyndns/4443/2 "2010-05-27T16:22:39Z")
Someone must have had experience with this? Davidc maybe?? ---
**Author:** ![awneil](https://avatars.discourse-cdn.com/v4/letter/a/49beb7/32.png) [@awneil](https://forum.sierrawireless.com/u/awneil)\ **Post date:** [May 27, 2010, 5:27pm UTC](https://forum.sierrawireless.com/t/periodic-updating-of-dyndns/4443/3 "2010-05-27T17:27:53Z")
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) > [@](#): > > Assume that I have a public, dynamic SIM account 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… ---
**Author:** ![mike\_rink](https://avatars.discourse-cdn.com/v4/letter/m/cab0a1/32.png) [@mike\_rink](https://forum.sierrawireless.com/u/mike_rink)\ **Post date:** [May 27, 2010, 6:23pm UTC](https://forum.sierrawireless.com/t/periodic-updating-of-dyndns/4443/4 "2010-05-27T18:23:11Z")
Awneil, thanks for the hearbeat idea with updating DynDNS. I will contact the SIM account support re my original question. ---
**Author:** ![awneil](https://avatars.discourse-cdn.com/v4/letter/a/49beb7/32.png) [@awneil](https://forum.sierrawireless.com/u/awneil)\ **Post date:** [May 27, 2010, 7:01pm UTC](https://forum.sierrawireless.com/t/periodic-updating-of-dyndns/4443/5 "2010-05-27T19:01:00Z")
> [@mike\_rink](#): > > Awneil, thanks for the hearbeat idea with updating DynDNS. For further info, try a search on “heartbeat”; eg, > [@Connectivity Fails after some length of time has passed](https://forum.sierrawireless.com/t/connectivity-fails-after-some-length-of-time-has-passed/4131/3): > > Two problems with this: The OP specifically said he wanted to avoid the overhead of reconnecting; When the network operator releases resources because you haven’t used the channel for some time, you don’t get any event to indicate that it’s happened! Or just ensure that you don’t leave the link idle - send some kind of “heartbeat” message to keep it alive… ---
**Author:** ![davidc](https://avatars.discourse-cdn.com/v4/letter/d/a183cd/32.png) [@davidc](https://forum.sierrawireless.com/u/davidc)\ **Post date:** [May 28, 2010, 1:36am UTC](https://forum.sierrawireless.com/t/periodic-updating-of-dyndns/4443/6 "2010-05-28T01:36:18Z")
Hiya, 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