Hello,

Soon I will be introducing Exchange 2013 servers into an Exchange 2010 environment that has been configured for SSL offloading according to this article. I haven't found any migration documentation that specifically mentions considerations for coexistence when 2010 is using SSL offloading. After I cut over my namespaces to the 2013 servers will there be any issues with traffic proxied from Exchange 2013 (not using SSL offloading) to 2010 that is offloading SSL?

With SSL offloading configured on the Exchange 2013 Client Access servers, coexistence works with Exchange 2007 and Exchange 2010.

You can get a better understanding by walking through this informative resources : https://technet.microsoft.com/en-us/library/dn635115%28v=exchg.150%29.aspx

Also, http://jaapwesselius.com/2014/02/28/exchange-2013-sp1-ssl-offloading/

Moreover, to accomplish the migration task in more easier way, I would also like to refer you on this automated solution (http://www.exchangemailboxmigration.com/) that could be a better alternative approach for you.

What I'm asking is whether coexistence works when SSL offloading is configured on the Exchange 2010 servers. The Exchange 2013 CAS will not be configured for SSL offloading.

Hi,

Based on my experience, I am afraid it will not work and clients may receive 403 error. Its recommended to enable on both host and proxy side.

Thanks,