Hi @kcraycraft1, welcome to the Community! You are correct. If the service or device is capable of using RADIUS or LDAP authentication protocol, then you can integrate it with Duo using our Duo Authentication Proxy server. It looks like Juniper SRX will support either RADIUS or LDAP, based on this thread from Reddit.
Some documentation that might help you are our Guide to the Duo Auth Proxy, as well as the Duo RADIUS and Duo LDAP reference docs.
Thanks for posting your question here! Let me know if you have any other questions, and I or someone else in the forum can follow up here 