Only tunnel types built on PPP support authentication with username and password:

A.✔PPPoE – Built on PPP, uses CHAP, PAP authentication.

B.✔OpenVPN – Supports user/password login for client authentication.

C.✘IPIP – A stateless Layer 3 tunnel; no authentication support.

D.✔PPTP/L2TP – Both are PPP-based and support username/password authentication.

E.✘EoIP – MikroTik proprietary Layer 2 tunnel; no username/password authentication.

Extract from MTCNA Course Material – Tunnel Types:

“PPPoE, PPTP, and L2TP are PPP-based and support user/password authentication. IPIP and EoIP do not.”

Extract from René Meneses Study Guide – Tunnel Protocols:

“Authentication (PAP/CHAP) is part of PPP. Use PPPoE, PPTP, L2TP, or OpenVPN for user logins.”

Extract from MikroTik Wiki – Tunnel Protocols Overview:

“Only PPP-based tunnels support authentication via username/password.”

===========