MX: mail.mydomainname.com (Priority: 10)

What does (Priority: 10) here exactly mean? HIGHEST priority or LOWEST priority? Are there just TEN priority levels, or more?

Learner

Lower numbers have higher priority. And there is no limit to how high the number can go - it is simply a measure of in what order you'd like delivery to be attempted.

Thanks Annette,

Can a reseller set such priority levels for his clients?

Learner

Most MX records by default have a priority of 10 on their mail settings. This is something that has to be changed at the server level directly into the domain's record. Since altering system files like this (and reloading the http daemon) requires root privileges, most resellers are unlikely to be able to provide this. However, most hosts would have no objections to doing this on someone's behalf.

Okie!

Thanks for the clarification again, Annette!

Guess this is another one of the numerous advantages of having root access to your own server :)

Learner

Priority 10 is a default for the highest (the lower the number the higher the priority, ironic perhaps).

For example I could have:
10 mail.webhostingtalk.com
20 mail2.webhostingtalk.com
21 mail3.webhostingtalk.com
348 mail4.webhostingtalk.com

However I don't have 4 mail servers, so I've probably only got '10 mail.webhostingtalk.com'. If your SMTP server can't reach the 1st server it will retry in X hours for X hours/days before sending it to the 2nd highest priority. If the 2nd server receives it, it will try the forward it to the 1st server when it is up, it will not send it to it's self again (otherwise you have a mail loop, dangerous resource hog), nor will it forward it to the 3rd server if it can't reach the 1st since it has higher priority.

Equally you could have mail priority number 1,2,3,4 or 40,80,120 (it doesn't matter, it just the order they're in). Hosts choose multiples of 10 rather than 1 so they can insert improved/new backup mail servers as they see fit without changing everything. Remember the days of BASIC, multiples of 10 was the standard :).

Originally posted by SysAdmin
Priority 10 is a default for the highest

SysAdmin, thanks for pointing that out.

(the lower the number the higher the priority, ironic perhaps).

I would like to clarify a little confusion I have here... its the confusion between the meanings of the words "LOWER than" and "LESSER in value"!!

According to what both Annette and you just mentioned above, I am now under the impression that the number 1 is both lower and lesser (in value) than 10... or is 11 lower than 10 (with reference to the subject of PRIORITY you are throwing light upon)?

Equally you could have mail priority number 1,2,3,4 or 40,80,120 (it doesn't matter, it just the order they're in).

So that means that the number ten in (Priority: 10) does not imply the speed with which mail is sent from the servers. It is just a number that denotes a heirarchy of servers... am i correct in my current assumption?

Learner

Say you have this config:


IN MX 0 mail.yourdomain.com
IN MX 5 mail.yourdomain.com
IN MX 10 mail.yourdomain.com

The smaller the number, the higher priority. In the example above, the priority would be as listed. The speed at which mail is delivered depends on the system, not on these entries.

So, just to clarify: what "sysadmin" was saying is that the default value is 10, so often 10 will be the lowest value you'll see (and thus the highest priority) while other values will be something like in his example: 20, 30, etc. Those records will have lower priority than the record with a value of 10.

But you could certainly configure it as in Annette's example, using 10 as your lowest priority and using values lower than 10 for higher priorities.

Uh... if that clarifies! :)

Just thinking of the mail priorities as in 'reverse' order.

E.g. 0 is the highest possible priority.
100 is a lower priority than 0.
200 is a lower priority than 100.

"etcetera, etcetera, etcetera.." The King of Siam

Thanks guys !!! This was a real cool explanation you all posted in this thread. It is all so clear now !!!

That's why I just love this forum !!! :love:

Learner

am always asking "etc. etc. etc." - because I must be the Prince of Siam :D