We have quite a bit of spam seeping through our Fortimail appliance. I have been manually updating the greylist to include frequent offenders' IP addresses.
I have yet to discover how to fill in a range of IP addresses. For example, I would like to block 208.*.*.*, but I when I enter wildcards, it indicates the entry is invalid.
I realize this is a hopeless long-term solution. We are just collecting email waiting for our network team (external) to have time to review the problem.
Any interim advise about entering IP ranges would be appreciated.