Hotmail DNS stupidities I figured I'd post this here as it's a little hurdle I've overcome that might help someone in the future. If you host your own email server(s) this one might be for you.
Our DNS is all hosted with Godaddy (Hate them as you will, I've never had an outage or problem) and apparently this problem affects Godaddy users as well as a handful of others on other services.
We were noticing email clients could not receive from hotmail addresses. To make things weirder, only some clients were affected.
They would get a postmaster message a day later with a "Relay not permitted" message. But strange thing was it wasn't being tagged with our server info. So it wasn't coming from us (so I thought).
Welcome to troubleshooting hell.
In the end what was happening, is only a COUPLE of Hotmail's outgoing servers were doing this.
In the DNS/MX lookup they would completely ignore our MX records. (Didn't matter how many we had or where they went). Instead hotmail (Only a handful of servers) decides to just send email to your default A record and screw anything you've specified in MX.
Low and behold on our default A record we have a web server, that does have email functionality, but it's not set up to work on those domains. It's essentially so the box itself can email system notices. So poof this is where the "Relay denied" came from. Apparently if you don't have a box that replies on port 25 on your default A record, it will then decide to deal with your MX, but that is spotty at best too.
Firewall rule blocking 25 from the outside world to our web server and problem solved.
Do you have an SPF record?
reply to voxframe
said by voxframe:Yes, thank you. I have a similar problem right now. I have one customer who randomly gets "Message Delayed, could not locate host" or something to that effect, and his message eventually fails. About 1 out of 10 messages. He can successfully send other messages while the other one is still failing. I host my own e-mail server. The customer is a large corporation who has their own server but for some reason they are relaying through Microsoft's mail dragon. You have given me some ideas to pursue. Thanks !
.... a little hurdle I've overcome that might help someone in the future. If you host your own email server(s) this one might be for you.
reply to voxframe
That's exactly the symptoms we were seeing.
And yes we have SPF and they're set up correctly.
Again though it's not outgoing email from us, it's Hotmail sending TO us. A handful of their servers don't do proper DNS/MX lookups and just send to your default A record. There's a few others who have had the same issues out there if you google around. Apparently it's a known issue of some kind.