If I do an MX lookup on our domain, I get a list of MX preferences with numbers.

Can someone explain how the MX preferences work. They don't start 1,2,3 and so on, but are shown as 6, 7, 10 , 15 & 5.

Does it take the lowest number and just send mail to that, then forward it on to the others in the lists or does it work in some completely different way?

Stefan

The reason they aren't sequential is because they're up to you to set, so people set one machine at 5 and one at 10, etc., to give room to put another machine between them or at the head of the queue. IIRC, the lower the number the higher the priority, i.e. the first machine to be tried.

yep bash is spot on. Most people put the first on 5, then 10 etc. When a machine does a lookup on your domain it will try the lowest preference first. If this fails then it will try the next one and so on.

Simon.

Thanks guys, that's what I assumed - seemed logical enough.

Our own servers are listed as 5,6 & 7 with our ISP's listed as 10 & 15.

I assume if our boxes are unavailable, then mail will get queued on the ISP's servers (since they're included) before eventually timing out?

Stefan

yes that is correct ozzy.

cheers m8.