On Thu, 23 Jun 2005, info wrote:
Many of my remote users send email from their residential DSL connections.
Charter and SBC for instance require that their customers use their SMTP
servers.
If I have an SPF record for domain.com and the MX record for domain.com
points at my corporate email server and my remote user sends an email from
the SBC SMTP server as employee(_at_)domain(_dot_)com, will the email get
blocked?
Short answer: YES
Long answer: If the SPF record does not mention SBC, then yes, the email will
get blocked (or at least tagged as SPF fail depending on receiver policy).
A good solution:
Configure your remote users to send domain.com email using SMTP AUTH
on port 587 to your corporate mail server (or any other port not blocked by
the ISP). This is supported in almost all email clients including Outlook,
Thunderbird, and Mozilla.
A quick and dirty solution:
Mention sbc.com in your SPF record. For example:
domain.com IN TXT "v=spf1 mx ?ptr:sbc.com -all"
--
Stuart D. Gathman <stuart(_at_)bmsi(_dot_)com>
Business Management Systems Inc. Phone: 703 591-0911 Fax: 703 591-6154
"Confutatis maledictis, flamis acribus addictis" - background song for
a Microsoft sponsored "Where do you want to go from here?" commercial.