JN0-106 User Interfaces Practice Question

You are a network engineer for a service provider that recently deployed a Juniper MX router at a new Point of Presence (PoP). The router is used to aggregate customer connections and exchange routes with upstream providers via BGP. After the initial configuration, you notice that the router is not learning any routes from one of the upstream BGP peers. You have verified that the BGP session is established (state Established) and that the peer is sending routes. You suspect that the issue might be related to the firewall filter or routing policy. You want to determine if any inbound routes are being rejected and why. Which command would provide the most direct information about why routes are being rejected?

⚠ Common exam trap

A common mix-up: candidates assume 'show bgp summary' or 'show route protocol bgp' will reveal route rejection details, but they only show aggregated statistics or installed routes, not the per-peer policy decisions that cause routes to be hidden or rejected.

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

✓

show route receive-protocol bgp 192.0.2.1

'show route receive-protocol bgp 192.0.2.1', is correct because it displays the exact routes received from a specific BGP peer along with any policy or filter actions applied (e.g., reject, accept). This command directly shows whether routes are being rejected and the reason (e.g., due to an import policy or firewall filter), making it the most direct diagnostic tool for the described issue.

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

✗
show route protocol bgp
Why it's wrong here
show route protocol bgp queries the routing table only, displaying BGP routes that have been accepted by import policy and installed as active or inactive prefixes. Routes rejected by the receiving policy never appear in the routing table, so this command cannot reveal rejected routes or the policy reason. It is a route-inspection command for the RIB, not a per-neighbor receive audit tool.
✓
show route receive-protocol bgp 192.0.2.1
Why this is correct
show route receive-protocol bgp 192.0.2.1 shows the exact updates received from that specific neighbor before they pass through the routing table, including the import-policy decision. The output marks each prefix with an 'A' (accept) or 'I' (ignore/reject) and, when rejected, prints the policy name and reason. This makes it the right diagnostic for verifying why a route from 192.0.2.1 was not installed, because it exposes the BGP input policy evaluation on every received prefix.
✗
show bgp summary
Why it's wrong here
show bgp summary provides an aggregated view of BGP peering sessions: peer address, AS number, session state, and counters for received, accepted, and active prefixes. While a mismatch between 'Received' and 'Accepted' counters can hint that some routes are being filtered, the command does not list the specific prefixes or indicate which policy rejected them. It is a session health and counter command, not a route-level policy inspection tool, so it cannot answer the question of whether a specific route was rejected.
✗
show firewall filter <filter-name>
Why it's wrong here
show firewall filter <filter-name> displays packet-matching counters and actions for the named firewall filter applied on an interface, which operates in the forwarding path on packets. BGP route policy is a completely separate mechanism in Junos: it evaluates NLRI at the routing protocol daemon during route exchange, not packet headers through a firewall filter. Therefore, this command shows nothing about BGP route acceptance and is irrelevant to diagnosing why a route was not installed.

Go deeper

JN0-106 User Interfaces Practice Question

Why each option matters

Option-by-option breakdown

Related to this question