Email conundrum

[Kent Multer]

Hi folks -- Sorry, this is somewhat off-topic, but I'm hoping one of you gurus will have a solution for me.

I have two email accounts that I use almost every day: one personal, one for business. The business account, which is hosted by Miva/Hostasaurus, works flawlessly all the time (thanks guys!). The personal account, kent "at" dallas.net, works fine for the most part; but I always get bounces when I try to send from that account to certain addresses, including several family members.

I've tried several times over the last year or two to get this fixed, with no luck. Dallas.net tech support (which is run by webhero.com) says there's nothing they can do about it. They've said the problem is related to IP addresses ... but that doesn't make sense to me, especially right now. For the last week I've been traveling, sending and receiving email from the Boston airport and my Mom's house in Maine. Wherever I go, the business account works fine, but the dallas.net account gets bounces. Also, I changed my home ISP a few months ago, from the cable company to AT&T U-verse, and the problem is unchanged.

A lot of the bounce messages refer to "SPF," but I must admit that I don't know what that means. I'm not expert on the low-level details of email protocols and server config.

Wherever I go, whatever ISP I use, the dallas.net account gets bounces for certain destinations, while the business account always works fine. How can this not be a dallas.net-related problem??? Can any of you tell what's going on here? I can post some of the bounce messages if that will help.

Thanks --

[ILoveHostasaurus]

Dallas.net is serving an SPF record consisting of the following:

v=spf1 mx -all

The purpose of an SPF record is to prevent forged emails going out for a given domain by letting the domain owner advertise to the world a list of servers they permit to send email using their domain in the From address. So in this case, dallas.net's SPF record says the only mail servers allowed to send email claiming to be from an @dallas.net address are the ones listed in their 'mx' record, which are:

dallas.net. 14400 IN MX 20 inbound02.dallas.net.
dallas.net. 14400 IN MX 10 inbound01.dallas.net.

The -all, with a hyphen, indicates that this is to be treated as an explicit list, no exceptions. This is as opposed to a ~all with a tilde, which means the list is recommended.

So, based on the above, if you send email claiming to be from an @dallas.net address to any recipient, and you use any mail server other than theirs, any mail server supporting SPF should reject the message as a forgery.

This suggests one of two things are occurring:

1) You're sending @dallas.net email using a server other than theirs. There is no way to make that work reliably, but switching to their mail server for outgoing, only for your @dallas.net address, should resolve the issue.

2) You are sending @dallas.net email using their own mail servers, but are still failing the SPF lookup. This would indicate that their DNS record is incorrect, or their mail server setup is incorrect. For example, if you use mail.dallas.net to send outgoing for that account, and the message arrives to your recipient from the server named mail.dallas.net, then they have a problem, because they have published to the world that the only two servers allowed to send mail claiming to be from @dallas.net are inbound02.dallas.net and inbound01.dallas.net. So in that case, they need to either fix their SPF record to include the missing legitimate server(s), fix their SPF record to use ~all instead of -all to make it not explicit, or fix their mail server config to route outbound mail through one of those two servers listed in the SPF.