So let's say I have IPHost Column that lists different IP addresses

A1 IPHost
A2 10.20.3.238
A3 172.16.16.1
A4 192.15.6.5
A5 12.10.10.1

and so on...

Then I have another workbook that also lists different IP addresses but I wanna find out all the unique values in the second workbook and add it to the spreadsheet above. What's the best way to do it?

So let's say the second workbook contains:

A1 IPHost
A2 10.20.3.238
A3 172.16.16.1
A4 142.6.3.22
A5 192.15.6.5
A6 184.16.3.19

How will I put 142.6.3.22 and 184.16.3.19 into the first workbook using Macros? And the reason why I'm asking is we have over 2,000 IP addresses on each workbook and I'm trying to find the easiest way how it could be done. Thank you in advance for all your help.