file1:

1164870782:172.16.0.1
1164870792:172.16.0.2
1164870102:172.16.0.3
1164870112:172.16.0.4


file2:

1164870782:172.16.0.1

resulting file:
1164870792:172.16.0.2
1164870102:172.16.0.3
1164870112:172.16.0.4