Rey Nacho Lives

I’m writing this to hopefully allow other people to avoid the issues I’ve had with one of the sites I support. This particular client’s business revolves around sending emails so it is obviously important that the end user receive those emails. Spam filters are more and more getting in the way. One thing you have to really think about when sending the email is “What will this email look like to the receiving server?” If you are on domain.com and you send an email using cfmail and the from address is a domain.com address, there is no problem. It’d be like sending that same message through Outlook using a domain.com address and domain.com relay (SMTP) server.

What if you have a form allowing a random user to send an email?This is where SPF filtering can block your message. They put in their from email address and to email address and whatever other data and that information gets stuck into the cfmail tag. Now, you might have an email address FROM someone@from.com TO someone@to.com. The email was sent THROUGH the domain.com server. Now if to.com’s server acknowledges SPF filtering, it will look at the dns record for from.com and look specifically at the TXT record. A smart DNS entry will list IP addresses that are able to send email. If the IP address of domain.com’s mail server does not appear in the DNS record of to.com, then the message will be blocked.

Here’s an example of the TXT record from domain.com:

domain.com       86400   IN         TXT       "v=spf1 ip4:xx.xx.xx.xx ip4:yy.yy.yy.yy ip4:zz.zz.zz.zz -all"

The first 3 ip addresses would be valid mail servers. The –all says to reject anything that is not one of those 3 ip addresses.

The way around this is to use a cfmailparam tag with a valid email address for domain.com (make an email address if necessary like info@domain.com). Here’s what the resulting code looks like:

<cfmail to="#to#"  from="#from#" subject="#subject#" type="html">
<cfmailparam name="sender" value="valid_email@domain.com">
.
.
.
</cfmail>

I hope this helps some people out

This entry was posted on Friday, September 7th, 2007 at 6:02 pm and is filed under ColdFusion. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.