Block IP
From Tech-Wiki
In order to block (or allow) connections based on static IP, or a data group, first, create a data group of type IP addr then use the code below (use 'not' if you want to allow instead)
when CLIENT_ACCEPTED { if { [class match [IP::remote_addr] equals ip_blacklist] } { reject } }
Or
when CLIENT_ACCEPTED { if { not ( [class match [IP::client_addr] equals SMTP-Relay_Data-Group] ) } { reject } }
Same using static IP hard coded:
when CLIENT_ACCEPTED { if { [IP::addr [IP::client_addr] equals xx.xx.xx.xx/xx] } { reject } }