The access token generated using JWT token expires in 15min. Is there a way to increase the expiry time? Also, the JWT token is generated using a private key, id there a way in ACS to trust the IP to prevent regenerating the JWT token?
Just to add you won't be able to extend the expiry of the tokens generated using Adobe I/O. Rather you can use the JWT libraries (https://www.adobe.io/authentication/auth-methods.html#!AdobeDocs/adobeio-auth/master/JWT/JWT.md) to generate token automatically when it's expires.
I am not sure why JWT expires in 15 min. By default Adobe IO JWT token expires in 24 hours from the time of issue.
More details discussed in JWT access token: How can I change the expiration?
Also ACS does not trust IPs to makeREST call, you will need JWT token and the recommendation is to have a short time expiry for the same.
More details on the parameters (includingf expiration date)- auth-methods