MX Record Configuration

[Kevin Darcy]

jerryyang_la1 at yahoo.com wrote:
> Hi.
>
> I currently have my MX records set as:
>
> mail.domain.com.     5
> mail2.domain.com.   10
> mx0.123-reg.co.uk.   15
> mx1.123-reg.co.uk.   20
>   
> This seems to work well, delivering email to my server (mail) and using
> my ISP (mail2) as a backup.  My ISP only spools the email, it doesn't
> host it as such.
>
> I'm thinking of changing this, and would like to know if there is any
> issue using "post.domain.com."  instead of using "mail.domain.com." Is
> there any issue using POST in an MX Record..
>
> I have a few issues with hosting my own email server, if my server or
> dsl goes down it takes a while for my ISP to spool it to me once my
> server is back.
>
> My ISP can host my email, to do this they would need to become MAIL. If
> I do this, I could become POST. My aim would be for Post to have a
> priority of 5 and Mail10.
>
> This way if my server goes down, my isp will get the email, but not as
> a backup server as an actual host. I can set my server to then check
> for any email using normal POP3.
>
> Would this work OK, having 2 different hosts. ??
>   
There's nothing magical about the first label of the name, in SMTP 
terms. The only thing that really matters in terms of SMTP failover is 
the preference value. If your box -- whatever it's called -- has a 
preference of 5 and your ISP's box -- whatever it's called -- has a 
preference of 10, then mail will be delivered to your box, if possible, 
and only if it is not possible will sending MTAs fail over to your ISP's 
server.

As for POP3, I'm not aware of any first-label "magic" there either. Just 
configure the name of your POP3 server into your POP3 client.

                                                                         
                        - Kevin