To bypass duo 2fa for a script or secure login etc on Linux you simply need to add the following to your SSHD PAM config (/etc/pam.d/sshd)
auth [success=2 default=ignore] pam_access.so accessfile=/etc/security/access-local.confYou will then need to create the access file and put your rules in for example
+ : ALL : 192.168.1.0/24
- : ALL : ALLFor information on the access file, see here