MX records only apply to the destination FQDN for the email. Spoofing
the destined domain to force everything through the relays is not a good
idea.
Most load balancing of an outbound relay requires you to force or
manually configure the relay in your mail programs, to point to the load
balanced resource (typically a VIP on a load balancing device, or the
server IP directly in regards to Round Robin DNS).
Round robin DNS, as bad as it is, is the cheapest way to 'load balance'
multiple relays.
Using a load balancing program, say pup, or commercial hardware from
vendors such as F5 or Citrix, would be the most stable and efficient
manner to achieve what you are after.
Tie the dns for your relay name to the VIP on the load balancer, and tie
your email servers to the VIP. This will force all your clients that use
the relay, to send email to the VIP, which will load balance your relays.
Regards,
Seann
On 1/13/2014 8:55 AM, Bauer, Stefan (IZLBW Extern) wrote:
Hi List,
thank you for confirming my opinions about DNS for load balancing. I share
your opinions.
@Peer - your advice is to use MX records. I don't think, MX-records can be used
for relayservers.
Our flow is:
Client -> Exchange - > Relayserver -> t...@example.com
I only see a use case for using MX-records the other way around:
t...@example.com -> Mailserver -> Exchange -> Client
In the latter case, I can balance with MX records to different Relayservers.
Not from inside to outside when a relayserver is used -correct?
Stefan
