As enterprises continue to register Sender Protection Framework records, hoping to thwart spam and phishing attacks, spammers are upping the ante in the war on spam and registering their own SPF records. Email security company MX Logic will report that 10 percent of all spam includes such SPF records, which are used to authenticate IP addresses of email senders and stop spammers from forging return email addresses. As a result, enterprises will need to increase their reliance on a form of white-listing called reputation analysis as a chief method of blocking spam.