Spam - SPF and Blackberry Handhelds

Tue 25 July 2006

Filed under Email

Tags Cool Security

A growing number of small businesses are using Blackberry handhelds. Microsofts services haven't taken off as strong, but in a year or two I suspect Microsofts products will be kings of the market.

For now, we have a wide range of Blackberry services. Most of my clients use the Blackberry Enterprise Server (BES) with Exchange. It's terribly expensive, the entire operation works nicely and people like it.

Some of my customers use SMTP + POP3, and one in particular uses this with a Postfix based spamfilter.

Postfix uses SPF (policy-spf.pl) and that, in turn, depends on internal SPF records to help reduce spoofing of addresses. Naturally sending from the Blackberry creates a bounce. We fianlly figured out how to set this up with SPF. It was a simple change:

Old Record

v=spf1 a mx mx:spamfilter.domain.com mx:gw.domain.com mx:gw1.domaim.com ip4:10.1.1.0/24 a:server.otherdomain.com -all

New Record

v=spf1 a mx mx:spamfilter.domain.com mx:gw.domain.com mx:gw1.domaim.com ip4:10.1.1.0/24 a:server.otherdomain.com ?ptr:blackberry.com -all

See? Just add the "?ptr:blackberry.com", and boom - all is good.


Comments


Up To Something © Joshua M Schmidlkofer Powered by Pelican and Twitter Bootstrap. Icons by Font Awesome and Font Awesome More