small question

I am newbie and working on exe (delphi code) file whose basic purpose is to upload data to fixed ftp IP address eg 123.12.123.123 ,but i want to edit the site IP address to say 123.123.123.123 by hex editor and save. Now what happens the file uploads data to 123.123.123.12 leaving the last digit 3. if I insert a decimal byte after 123.123.123.12 then the exe file gets corrupted.

Thanks kindly advice