Re: [exim] DNS Question

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Author: Fred Viles
Date:  
To: exim-users
Subject: Re: [exim] DNS Question
On 7 Jan 2005 at 16:24, Marc Perkel wrote about
    "[exim] DNS Question":


| How do you set up an A record to return more than one IP address?


"An" A record contains one IP address, by definition. But you can
have any number of A records owned by the same name. Any type=A
query for the name will return the entire matching set of A records
(just like MX records and most other record types).

| When it
| is set up this way - does it return ALL the IP addresses or randomly
| just one of the list? or is that configurable.


All, in no particular order.

| I have this idea for front end spam filtering servers in diverse
| geographic locations, all on the same name so that the email might go
| randomly to any one of these servers and then funneled securely to the
| "real" server where it is read by the end users.
|
| So - can I do this?


Sure. You can have multiple MX records having the same priority
value, and each of the MX name values can own multiple A records.

I would recommend multiple MX rather than multiple A. You can't rely
on the SMTP clients to notice that there is more than one A record,
which matters if one or more of the hosts is down or unreachable.

- Fred