Didn't look before but that IP is associated with Dahau's P2P service (or what it was at the time):
Same as I and others saw with some older Dahua cams, they'd try to access P2P even if you had it turned off. Nothing much you can do about it but block it which you're already doing, redirect the gateway, or maybe update firmware if you want to take the usual risk.
Old posts noting same:
My new SD29204T seems to be trying continually to contact dms.easy4ipcloud.com. This appears related to their "Easy4IP App" as shown here: http://www1.dahuasecurity.com/products/easy4ip-app-1363.html I'm assuming that it's a typical find and register my IP for easy access through the...
ipcamtalk.com
I have a conventional system with 4 cheap Chinese IP cams and a Windows PC running BI. After the major virus attack all over the world a few months ago, I became aware of the risk that the cheap Chinese cams may function as sleeping soldiers for virus attacks, so I blocked the IP cams for...
ipcamtalk.com