If using R2016b, you can use the new string type. It is then trivial to split the strings in one go with split and then convert to numbers with double:
numericip = double(split(string(X), '.'))
Otherwise, you can use the old-fashioned strsplit + str2double wrapped in a cellfun to create a vector per ip string. You have to use the 'UniformOutput', false option to store these vectors in a cell array, and then convert the whole cell array back to a matrix with cell2mat.
numericip = cell2mat(cellfun(@(ip) str2double(strsplit(ip, '.')), X, 'UniformOutput', false))
The first option is significantly faster (and less to type).
