if the 1.1.2.254 is existing in my database !! use the next 1.1.2.253 proplem

Question

i have an IP address inside my database like 1.1.2.254 1.1.2.253 1.1.2.252

i need to make loop if the 1.1.2.254 is existing in my database !! use the next 1.1.2.253