We had our transactional e-mails blocked temporarily the other day by Comcast thinking our mailing IP is a spammer. HostingRails quickly fixed it, but I'm wondering if there's anything else we can do to decrease the probability of it happening again.
Anyone using Sender ID? What about DomainKeys? Is it possible to have our e-mails signed with DomainKeys in a shared host environment? Can the MTA do it automatically for us?
I've heard that if you're sending mail between users, you should either add a Sender: field with an e-mail for the site or put the site e-mail in the From: and change the Reply-to: to the originating user.
Any other ideas? We're sending mail through the MTA rather then directly over SMTP since we want the reliability that the MTA offers (retries, etc.).
Thanks,
Maurice