Which protocol Authenticates network traffic between hosts end without encryption?

PPTP encapsulates PPP frames and typically uses MPPE encryption, providing tunneling with encryption rather than authentication alone.

GRE is a tunneling protocol that provides neither authentication nor encryption of traffic by default.

IPSec AH computes an HMAC over the IP header and payload to authenticate the data origin and verify that packets have not been tampered with in transit. Critically, AH provides no confidentiality - the payload remains in plaintext - which directly matches the requirement of authenticating traffic between hosts without encryption. This distinguishes AH from ESP, which adds encryption.

IPSec ESP provides both confidentiality through encryption and optional authentication, so it does not satisfy the requirement of authentication without encryption.