Assuming that you want to store the data as strings, and that the delimiters are 'whitespace' and ':'.
filepath = 'the_path_to_your_file.txt';
str = fileread(filepath);
cstr = cstr(~cellfun('isempty',cstr));
ips = regexp(cstr,'(\d+\.?)+','match');
This should give you a cell array of cell arrays containing the defined ip's.