IP ranges are not supported (only single hosts and CIDR) but there is a (public domain) tool that can convert IP ranges into CIDR: http://www.spamshield.org/cidr-convert.c
dump_tree function has a bug: "v >> 24" should be written as "v >> 24 & 0xff" instead. After fixing it this tool can be used as follows. portscan -p 80 `echo 192.168.1.1-192.168.1.20 | cidr-convert` ipcalc has similar functionality but writes additional line and can't aggregate overlapping ranges: $ ipcalc -r 192.168.1.1 192.168.1.20 deaggregate 192.168.1.1 - 192.168.1.5 192.168.1.1/32 192.168.1.2/31 192.168.1.4/31