What does the block “SPF/Caller ID” mean?
An SPF block is one generated by the SENDING DOMAINS dns server. The sending domain has posted, using an spf record, the IP addresses of machines allowed to send mail for their domain. This SPF record tells RECEIVING mail servers to block all mail that comes from any IP address not listed in it offical SPF record. The mail that is blocked, if legitimate, is usually sent from a home office or from on the road (hotel, starbucks, etc..). In that case the mail will be sent out using the local ISP’s mail server instead of the Senders actual Mail Server. SPF records STOP spammers from spoofing domain names by blocking mail coming from un-authorized mail servers. There are several ways to “FIX” this problem 1. The sender should set, in their mail client, their outgoing SMTP server to their domains actual mail server. This may require special setups by the domains network administrator. If their domain has webmail access they can use that as well. Webmail sends out mail via the authorized mail
