Why is my iPhone connecting to random IP addresses?

Hi there,

Recently I got a new router from my ISP, and from the built-in firewall I found out that my iPhone is randomly connecting to IP addresses with a Japanese source IP address (fyi, I am located in The Netherlands).

I have already restored my iPhone using iTunes DFU mode, but even when I haven't installed any apps or restored my iPhone from the iCloud, my iPhone seems to make these connections. Again, the source address is not mine, and both my cable company and mobile phone company don't have any associations with a Japanese company. The target address constantly changes and have been 241.182.199.179, 77.134.11.241, 72.56.129.194 and 129.55.142.199.

This iPhone is a refurb after I got it swapped at the end of July 2016 at the Apple Store in Haarlem, The Netherlands.

Is this the work of a malware package?

I hope someone can explain this to me.

- Jeffrey