Hi @colohost, thanks for your question! While there are no existing Duo integrations for either Apache or Nginx at this time, there are feature requests for these which you can request to be added to, either through the Duo Support team, or your Account Executive or Customer Success Manager if you have one.
We normally direct people to use the Duo Web SDK for protecting Apache, and I found this documentation on their site for Guacamole that also recommends the Web SDK solution: Chapter 8. Duo two-factor authentication
There are a few other solutions I can recommend based on what I’ve found in searches that seem to work for other users (untested and unsupported by us), but none use SAML, so I’m not sure if they will work for you.
@officialJCReyes and @nug have both posted in the community before about Apache and Nginx, so perhaps they can share what configurations they are using?
Not exactly the answer you were looking for, but I hope that helps!