350-401 Infrastructure Practice Question
A network engineer is configuring a Cisco IOS switch and needs to ensure that a port connected to a server is placed into the forwarding state immediately when the link comes up, without going through the listening and learning states. The engineer also wants to protect against accidental loops if a switch is connected to that port. Which feature should be configured on the port?
⚠ Common exam trap
Many exam-takers confuse PortFast with other spanning-tree enhancements like UplinkFast or BackboneFast, which serve different purposes and do not provide immediate forwarding on access ports.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
PortFast with BPDU Guard
PortFast transitions a port immediately to forwarding, which is ideal for server connections. BPDU Guard disables the port if a BPDU is received, preventing loops if a switch is mistakenly connected. The combination provides both fast connectivity and loop protection, making it the correct choice for this scenario.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
UplinkFast
Why it's wrong here
UplinkFast is a legacy feature designed to improve convergence when an uplink port fails on a switch with redundant uplinks. It is not used on access ports connected to servers. It does not provide immediate forwarding on link up, nor does it protect against loops on a server port. Therefore, it is not the correct choice.
- ✗
BackboneFast
Why it's wrong here
BackboneFast is a legacy feature that speeds up convergence when an indirect link failure occurs in a switched network. It is not applied to access ports and does not provide immediate forwarding or loop protection on a server port. Thus, it does not meet the requirements.
- ✓
PortFast with BPDU Guard
Why this is correct
PortFast allows a port to transition immediately to the forwarding state when the link comes up, bypassing listening and learning. BPDU Guard disables the port if it receives a BPDU, protecting against accidental loops if a switch is connected. Together, they meet the requirements for fast server connectivity and loop protection.
- ✗
Root Guard
Why it's wrong here
Root Guard prevents a port from becoming the root port by ignoring superior BPDUs. While it can protect against certain topology changes, it does not enable immediate forwarding on link up. It is typically applied to ports where the root bridge should not be elected, such as on the network edge, but it does not provide the fast transition that PortFast offers.
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JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official Cisco exam blueprint
This 350-401 practice question is part of Courseiva's free Cisco certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the 350-401 exam.