I'm having issues with Hik DVR's not updating ip address changes. I've been in the Dyn Community Forum and others have had similar issues but I can't get any clear answers. I did actually talk with someone at Dyn (about a month ago) and he had me change my password, log out, log back in and change it back to original password. He said it had to do with the updater client key (though I'm not using it in my DVR or routers) somehow and this "should" fix it.
Well, that didn't seem to work. I had two clients that can't get access today. With the help of OvrC I was able to check the local wan ip and then log into my Dyn account and see that they were not the same. The Dyn had the old one while the WattBox had updated. I was able to input the new ip in the clients Dyn account and that fixed it, for now.
For those that use Dyn, this is how I have it set up in the DVR's:
DDNS= DynDns
Server Address=members.dyndns.org
Device Domain Name=xxxxxx.mywebsite.com (xxx=clients name in Dyn account)
User Name=my log in user name at Dyn Dns
Password= my user password at Dyn Dns

In the DVR I've also set the DNS Server to:
Preferred DNS Server= 8.8.8.8
Alt DNS Server=8.8.4.4

I'm having the same issue! Haven't spent much time trying to get it to work.

Let's try to figure it out...I'm surprised no else here is having this issue. They may be using another DDNS service. If anyone reading this is using another DDNS provider who are you using?

Have you or are you able to put the DDNS information in the router instead of the DVR?

If so, does it update from there?

Can you tell if it's a Dyn thing or a Hikvision thing?

Can you just switch the clients over to the free WattBox DDNS service and ditch Dyn?

No, I haven't. I don't always "own" the network so if they swap or do a factory reset it'll affect it. I know, at least it'll work if the ip changes. When we do take over the network we use the Edge Lite and honestly I couldn't find anywhere to do it. I believe you have to do it via SSH and not familiar with that.

I honestly don't know at this point

I'm trying to use a paid service that has more options as to email me (or client) when it's been disconnected from the network and use my companies url versus a company they're not familiar with. Honestly I thought I'd here from more people on this particular issue.

Use hikvision's own ddns, works like a charm every time
www.hik-online.com

Do you know if you (or client) can set up to be emailed if device drops off the DDNS service?

Use uptimerobot.com to ping the DDNS URL and port you have forwarded on the DVR. It will send an email when down, you can add multiple people it emails also.