NSE7 Troubleshooting and Diagnostics Practice Question
An administrator configures BGP route advertisement but the routes are not being sent to the neighbor. The BGP session is established. What is the MOST likely cause?
⚠ Common exam trap
A common mix-up: candidates assume a BGP session being established guarantees route advertisement, but BGP requires explicit 'network' statements or redistribution to inject prefixes, and the session state only indicates TCP connectivity and BGP open message exchange.
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
✓
The 'network' statement is missing for the desired prefix
The BGP session is established, so Layer 3 connectivity and TCP port 179 are working. The most common reason for routes not being advertised to a neighbor is that the 'network' statement is missing for the desired prefix. In BGP, the 'network' command does not advertise the prefix unless it matches an exact route in the IP routing table; without it, BGP has no prefix to send, even if the session is up.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
The BGP administrative distance is set too high
Why it's wrong here
Administrative distance governs which route source is installed into the routing table locally; it has no effect on advertisements sent to a BGP peer. Distance matters when selecting between competing protocols for the same prefix, not when deciding what eBGP or iBGP exports.
- ✗
The BGP neighbor has the wrong update-source interface
Why it's wrong here
An incorrect update-source breaks TCP reachability, so the BGP session would fail to establish or flap. Since the stem states the session is established, this cannot be the cause; update-source matters when peering addresses differ from the egress interface used for the TCP connection.
- ✗
The route is filtered by a route-map
Why it's wrong here
Route-maps can filter, but the most common initial missing configuration is the network statement.
- ✓
The 'network' statement is missing for the desired prefix
Why this is correct
In BGP, the 'network' statement is what injects a prefix from the routing table into BGP for advertisement. Without it, no matching route is originated, so the established session carries no updates for that prefix to the neighbour.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This NSE7 practice question is part of Courseiva's free Fortinet 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 NSE7 exam.