Access private IP from Public internet

hi,
i would like to access DVR in internal network from internet, and also i have couple more DVRs in internal network in different buildings.
Option1: i would like to install DNS server and point my external example.com DNS name to DNS server then DVR name as host name in DNS server
Option2: give more public IPs in LAN D-link routers and point dynamic DNS name to them.

could you please suggest me which one is best and reliable for me.

thank you
cctv.jpg

isn’t a security issue to make the DVRs reachable from the internet? i would suggest to use a VPN connection to access the internal devices.

Pretty sure this is a duplicate thread.. http://forum.mikrotik.com/t/access-private-ip-from-public-internet/74050/1