IronPort HA/Load-Balancing

[sudip.acharya1]

Hi,

Is it possible to take 2 ESA's and specify one for inbound messages and the second unit for outbound messages? Incase of a H/W failure, use the other unit as a HA peer?

[Ken Stieers]

Yes.

For inbound, the easy/free way is to set up an MX record for each ESA with different weights. Systems sending mail to you should try the ESA with a lower weight first. If it doesn't respond, it will try the next one...

For outbound, it depends on the mail system, and some don't do it as well as others...

[sudip.acharya1]

Ken,

For the outbound mail, the email system is Exch2013.

[Ken Stieers]

So the first though that comes to mind for outbound exchange would be to create 2 Send Connectors, each one pointed at a different ESA and give one more weight...

That won't work because if the ESA is down, that connector doesn't become "down" as well, so mail will route to it, and queue.

Create one connector, add both ESA as outbound hosts, and let it go at that.

[Robert Sherwin]

One valuable guide:

http://www.cisco.com/c/dam/en/us/td/docs/solutions/CVD/Aug2014/CVD-EmailSecurityUsingCiscoESADesignGuide-AUG14.pdf

-Robert