and another says that i need more than 1 ...[/qoute]
I don't see where it says you need more than one, only that you have two and it tested two; perhams I'm missing something.
However there aren't many good reasons to have multiple MX records, and there are some good reasons to
not have multiple MX records.
Here's a short history of mail deliery issues over the years:
Before there was TCP/IP (it's the name of the protocol the Internet uses; from now on in this post we'll just call it "the Internet") there were lots of other ways to deliver mail (and in fact, of all the mail servers in current usage, sendmail still knows how to deliver by all those other methods; the others just stick to delivering email over the Internet.
Those non-Internet ways to deliver email were literally costly (which is where the term "cost" comes from when referring to MX records); they required automated telephone calls between computers.
Those telephone calls were charged by call-length (similarly to how many people pay for long-distance calls today) and call distance (calls over longer distances cost more than calls to nearby areas (this model has all but been abandoned by most telephone companies for calls within the same country).
The least costly way to send an email was to send it to the mailserver closest to it's final destination; usually the email server where the user would actually read his/her emailt (the system actually predates POP clients; people needed an account on the server to read their email).
But if that server wasn't available for some reason (perhaps, like some people we know, it was too busy to answer the phone) it made more economic sense to get the email as close as possible to the destination server. So if there were multiple MX (it stands for "Mail Exchange) servers available for the domain, it would try to send the email to the next higher cost server.
Why? Because doing so could mean (if the second server was working) only one more phone call; only one more try, rather than lots of phone calls and lots of tries. (Note that it wouldn't necessarily be higher cost for the sender, but a higher total cost, since the second MX server would have to keep trying to send it to the main MX server.)
Yes, now the second MX server has to keep trying, but usually one entity (company?) would own or control both servers, or else the two would have a mutual agreement to spend the extra money to help each other get their email.
In the early days of TCP/IP we actually paid for the number of bytes we sent, so the cost model continued for some time; long enough for multiple MX records to be established in the mindset of most administrators of that time. (We'd want to send the email within as few tries as possible.)
Now most of us no longer have an economic incentive.
And running a second mailserver for most of us has actually become a liability, in that the additional nameservers don't know who the actual end recipients are, so they must accept email for all email addresses at the domain.
Then they keep trying to deliver to the lowest cost MX record until they can, or until their retry times (coded into the mailserver) have been exceeded, when they try to return the undeliverable mail.
Note they may also end up with undeliverable email because when the primary mailserver does start answering again, it will tell the second mailserver that no account exists for a given email address.
Either way, the second server must now try to return the email, and if (usually in the case of spam) it can't because the return address isn't valid, that email is stock on that mailserver's queue (often in enough quantity to severely impact it's effectiveness) until the delivery retry times have again been exceeded.
Note that this explanation is vastly oversimplified, and that there are some reasons to have MX records for backup mail servers. However, in the circumstances of a single server receiving email for a small hosting company, a second MX record is
not necessary and does waste resources.
I have now a pop mx 20 and a mail mx 10 ...
Should i just use a mail mx 10 ?
I'd say yes.
Jeff
