https://community.cisco.com/t5/network-access-control/ise-smtp-server/m-p/4004218#M454767 Secure SMTP was a feature just introduced in ISE 2.7. You will not be able to use secure SMTP in 2.6 or older since it does not exist. <BR /><BR />2.7 was just released, I would be very cautious before moving production to it since little is known about its general stability. Fri, 27 Dec 2019 20:55:05 GMT Damien Miller 2019-12-27T20:55:05Z https://community.cisco.com/t5/network-access-control/ise-smtp-server/m-p/4004209#M454766 <P>Hello friends,</P><P>&nbsp;</P><P>I am trying&nbsp; to send the email to Guest Users with their credentials to login to the Guest-Wifi. Our SMTP server only supports TLS Port 587, but looks like ISE still using the non encrypted TCP/25. Is there any other way we can make this work.</P><P>How to add the Authentication for external SMTP server on ISE?</P> Fri, 27 Dec 2019 20:07:04 GMT https://community.cisco.com/t5/network-access-control/ise-smtp-server/m-p/4004209#M454766 prathyusha 2019-12-27T20:07:04Z https://community.cisco.com/t5/network-access-control/ise-smtp-server/m-p/4004218#M454767 Secure SMTP was a feature just introduced in ISE 2.7. You will not be able to use secure SMTP in 2.6 or older since it does not exist. <BR /><BR />2.7 was just released, I would be very cautious before moving production to it since little is known about its general stability. Fri, 27 Dec 2019 20:55:05 GMT https://community.cisco.com/t5/network-access-control/ise-smtp-server/m-p/4004218#M454767 Damien Miller 2019-12-27T20:55:05Z