trying to set up dvr what is dhcp and ddns do i need it

DHCP means that your router / network will automatically assign an internal IP address to any new devices added to it.

DDNS refers to Dynamic DNS - Some IP addresses assigned by various internet providers can change occasionally as opposed to truly static IP addresses.

If you think of the IP address as being like your phone number at home, if anyone calls your number then they will get through to you. If your number changes overnight then the calls to you will end up elsewhere.

If possible always ask your internet provider how much they charge for a static IP address. If they cannot provide this then a dynamic DNS can help resolve it by swapping your IP address for an address which simply points at your 'current' IP.

For example your IP is 1.2.3.4 - you set up a DDNS called my.address.freeddns.com using this name instead of the IP where requested. Any information then sent to my.address.freeddns.com will point to 1.2.3.4 - If your IP changes, to 6.7.8.9 then my.address.freeddns.com will instead point to this.

The only requirement to get this working practically is to either have your PC online permanently with a client to update the DDNS details with the latest IP - OR to use a router / modem / IP DVR, which supports DDNS directly.

'J