email mx

[#1]

I'm just setting up an email server on my Virtual Private Server with Postfix / Dovecot. I am sure I will not get things right first time. So, does anyone know if I change my MX records from the Plusnet email system to my VPS, can I set up an MX record to the old Plusnet email as a backup? If so what what addresses etc?
Thanks

[#2]

I don't think our domain control system will allow you to do this I'm afraid.

[#3]

OK. 
As suspected, I did mess it up. No email.
my settings on domain for email
leftfield: blank type: mx pr:i 3 rightfield: my servers ip number
When I went on pingability.com it showed my server name as my server's ip number.my domain name which has really confused me.
I use similar settings for www and e.g. git and they work.  Must I use a left field?
thanks

[#4]

You should specify a hostname for a MX record not an IP address.

Quote

The characteristic payload information of an MX record is the fully qualified domain name of a mail host and a preference value. The host name must map directly to one or more address record (A, or AAAA) in the DNS, and must not point to any CNAME records.

- http://en.wikipedia.org/wiki/MX_record
Cheers,
A.

[#5]

Thanks Avatastic, I misunderstood the Plusnet layout, so I have created an address record, and a mx record.  It is taking a long time for this change to propagate so I will see tomorrow.

[#6]

Just taken a look and your DNS records seem fine.