Does Red Shift have filters to keep spam from getting through?
Network filters are exactly what they are listed as, network filters. They are an all or nothing solution that defers all mail or lets all mail through from remote networks. When spam makes up a small portion of the e-mail that we receive from a network we will not consider adding them to the filters. In cases where an overwhelming majority of incoming e-mail from a certain network is spam, that network will most likely be added to the filters.