I have been running an Exim4 email server servising several domains for many years, mostly without issue. I do have SPF configured and it is running on a commer

I have been running an Exim4 email server servising several domains for many years, mostly without issue. I do have SPF configured and it is running on a commercial VPS server. For spam defence I use grey-listing based on DNSBL lookups, some standards-enforcement ACLs and then SpamAssasin via MailScanner on the messages that get through.