>> It seems people can come to wrong conclusions due to the syntax which is used at different systems with different internal meanings. The feature cannot of course be changed, but maybe it'd worth to update the documentation. I see, are you thinking of adding something like this to the manpage: -s --source address[/mask][,...] Source specification. Address can be either a network name, a hostname, a network IP address (with /mask), or a plain IP address. It can also be a plain IP address with /mask, in which case the mask will be applied to the plain IP address to compute the associated network IP address. Note that in the latter case, the plain IP address is automatically reinterpreted (i.e. modified or re-calculated) by the system as a network IP address. I think this would at least raise attention to a beginner to be cautious. Also, I used the terms "modified" and "re-calculated" as synonyms for "reinterpreted". I get the impression this would be more agreeable to some users?