DUO VPN Installation Guide The VPN is Who needs to use CDNIS VPN to access: HR Portal, Purchasing Portal, or other CDNIS services when they are outside of the campus. If you need to use this service, please follow the attached guide to and the latest link from DUO for enrolment. Please visit OneDoor if you need any other assistance. Enrollment email from "<no-reply@duosecurity.com>" with the subject "Duo Security Enrollment" is a legitimate email from DUO.