Yes. One of the flaws of SPF. However, you can also use a weaker SPF record that says basically that you don't know what mail server it is coming from. Not much point in that except to say that you're using SPF, though I suppose it might be possible that a particular mail admin might penalize sites that haven't implemented SPF in spam weighting.
A caveat on the above flaw: SPF does have the ability to reference another domains SPF records, so if the ISP in question has implemented SPF you should be able to "inherit" their SPF implementation by referencing it in your own. I haven't had an occasion to try that out yet, though. Darin. ----- Original Message ----- From: "David Dodell" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Saturday, September 11, 2004 9:45 AM Subject: [Declude.JunkMail] SPF Records and Off-Network Customers I have a customer who I host their domain. Up to last week, all of their email was sent through us using SMTP Auth. However, his local ISP started blocking port 25 outbound, so he is now forced to use the local ISP for sending his outbound email. In setting up his SPF records, it appears if I understand this correctly, that I'm going to have to list his ISP IP addresses of all of their outbound MTA boxes? If so, isn't this going to be a major hassle for SPF verification when individuals are using virtual domains but using local ISP for outbound SMTP service? David --- [This E-mail was scanned for viruses by Declude Virus (http://www.declude.com)] --- This E-mail came from the Declude.JunkMail mailing list. To unsubscribe, just send an E-mail to [EMAIL PROTECTED], and type "unsubscribe Declude.JunkMail". The archives can be found at http://www.mail-archive.com. --- [This E-mail was scanned for viruses by Declude Virus (http://www.declude.com)] --- This E-mail came from the Declude.JunkMail mailing list. To unsubscribe, just send an E-mail to [EMAIL PROTECTED], and type "unsubscribe Declude.JunkMail". The archives can be found at http://www.mail-archive.com.
