Greenbone GSM/OpenVAS CIDR file

A consideration when creating a scan task is to configure it for a single host, multiple hosts via range, or CIDR format. A limitation that exists is the number of hosts that a single scan can be performed on. This limitation is, "The maximum netmask is /20. This equals 4096 addresses." If you're attempting to import a file that contains the hosts, and networks to scan, you may come across a error message that is not overly helpful. The error message is, "Error in host specification". The error message may be correct if you fat fingered one or more entries per line in the file that GSM doesn't like. The error message may instead not be correct in the sense that there is no problem with formatting, but in the number of hosts specified in the file. This particularly comes into play if you're specifying large class numbers, which of course means a large number of hosts. For example, despite the limitation being 4096, specifying 16 entries with a C class /24 CIDR notation, the file will still throw the error. Reducing the file by one to 15 entries and moving the 16th entry to another file to be used for a scan task will give the desired results.