How do you do a lookup of an IP address using your database?

• If you are using a database like MySQL, you can use the inet_aton  (https://dev.mysql.com/doc/refman/8.0/en/miscellaneous-functions.html#function_inet-aton) function and a query will look like this:
  
  SELECT * FROM the_ip_table WHERE start_ip < INET_ATON('201.17.127.247') AND end_ip > INET_ATON('201.17.127.247')
• if you are using postgresql, you can create a function to convert the start_ip and end_ip to integers and then use the BETWEEN function when looking up an IP. Here is an example:
  
  
  

  -- function to convert ip to int
  CREATE FUNCTION ip2int(text) RETURNS bigint AS $ 
  SELECT split_part($1,'.',1)::bigint*16777216 + split_part($1,'.',2)::bigint*65536 +
   split_part($1,'.',3)::bigint*256 + split_part($1,'.',4)::bigint;
  $ LANGUAGE SQL  IMMUTABLE RETURNS NULL ON NULL INPUT;
  
  
  -- sample query using the function
  SELECT *
  FROM ip_geolocation
  WHERE ip2int('200.233.1.2') BETWEEN ip2int(start_ip) AND ip2int(end_ip)`