Kept fooling around with this and found a website that validates SPF records.  (link if anyone needs it)  Looks like my SPF record is valid, so evidently that is not why Hotmail is blocking me.

As a work around, I thought I'd add a transaction filter for hotmail RCPT users. I use the F (FAIL) action command, with a 554 response and a message to the hotmail user that I am unable to reply. Works great, other than the fact that Hotmail does not show the user the error message. Why am I not surprised?

I was wondering, though, is there a way to specify when the 554 response is sent? I'd rather send it after the DATA command, so that at least the email is in my logs and I can go read it.

Thanks!

Using Mercury 4.72 with the MercuryC smarthost relay through the ISPs mail server

Everything worked peachy until just recently.  Started getting 553 service unavailable rejections from hotmail users.  Did a little digging and it seems that I needed something called an SPF record.  Used an MS wizard to create the SPF record and updated the DNS.  Created a dummy hotmail account and verified that everything was OK.  But ...it turns out that I still can't send to hotmail users ... except to the dummy account that I created.  Go figure.

Also verified that ISP's servers are not blacklisted anywhere.  Any thoughts or suggestions?

> Using Mercury 4.72 with the MercuryC smarthost relay through the ISPs mail server
>
> Everything worked peachy until just recently.  Started getting 553 service unavailable rejections from hotmail users.  Did a little
> digging and it seems that I needed something called an SPF record.  Used an MS wizard to create the SPF record and updated the DNS.
> Created a dummy hotmail account and verified that everything was OK.  But ...it turns out that I still can't send to hotmail users ...
> except to the dummy account that I created.  Go figure.

I've never had a SPF record and never will but I do not have any problem at all sending to any Hotmail address.  You do need a PTR record pointing to a valid SMTP host though.  

It's possible that the ISP's server does not have the proper records.

>
> Also verified that ISP's servers are not blacklisted anywhere.  Any thoughts or suggestions?

Could you provide the host names being used for verification?

Hope you had a good Christmas!

There are multiple MTAs, but the latest one was nlpi129.prodigy.net. nlpi157.prodigy.net has also been rejected by Hotmail. Unfortunately, I can't figure out how to display headers in Hotmail, so I'm not sure what MTA my test messages were sent from.