Find and Display Match Text between columns

Hello,

I have a work sheet listing Client names in column A and IP for each client in column B. Column C has a list of IPs which I need to match up to a client name and I would like to display that client name in column D.

A B C D
Client 1 uniqueIP1 UniqueIP to match agains column B Display Client name from A1
Client 2 uniqueIP2 UniqueIP to match agains column B Display Client name from A1
Client 2 uniqueIP3 UniqueIP to match agains column B Display Client name from A1
Client 2 uniqueIP4 UniqueIP to match agains column B Display Client name from A1
Client 3 uniqueIP5 UniqueIP to match agains column B Display Client name from A1
Client 4 uniqueIP6 UniqueIP to match agains column B Display Client name from A1

Please let me know if you can help me generate an excel function to do this match. I have 100s of IPs to go through.

Thank you,
Zig