I saw one how-to covering this, but it didn't look the same as my SpamSnake setup. Anyway here is my issue: One of our vendors is being rejected on an SPF check. Someone told me that they had very recently changed ISPs. Here's a log entry from Postfix: Maybe they haven't updated their SPF record after the ISP change? Anyway, is there a way to whitelist their domain(s) in Postfix so my users can receive mail from them? UPDATE: after checking a few online dns query sites, I have determined that there is NO SPF record for either of their domain names. This doesn't sound right... If anyone wants a crack at this, their email server's name is mail.cbsinsne.com and their email address domain is fainsgroup.com.