It is in ARFF format. If you're not familiar with ARFF, it's basically that everything under the @data marker is in CSV.
For clarification, I am trying to use the dataset on Weka but the option to use Naïve Bayes is greyed out.
Every classifier, clusterer, filter etc in Weka can only handle certain types of data, i.e., its capabilities (which you can check in GUI). These capabilities are then compared against the data. In case of a mismatch, the GUI won't allow you to apply the algorithm.
Long story short: the dport attribute is of type string which NaiveBayes can't handle. You can convert that attribute into a nominal one using the StringToNominal filter.
