Lower the customer maximum-prefix from 100 to 50¶
Case 7 of the Network Change Verdict Corpus. Category: hygiene. Expected verdict: safe (an experienced operator would approve it).
Why it is expected safe¶
Tightening a safety limit that is still far above the customer's real count.
The config change¶
Against the FRR configs of the base lab:
--- a/pe1.conf
+++ b/pe1.conf
@@ -53,7 +53,7 @@
network 192.0.2.0/24
neighbor 10.0.1.2 route-map FROM-CUSTOMER in
neighbor 10.0.1.2 route-map TO-CUSTOMER out
- neighbor 10.0.1.2 maximum-prefix 100
+ neighbor 10.0.1.2 maximum-prefix 50
neighbor 10.0.2.2 route-map FROM-UPSTREAM in
neighbor 10.0.2.2 route-map TO-UPSTREAM out
neighbor 10.0.3.2 next-hop-self
What each strategy said¶
The expected verdict was committed to git before any run. All three strategies tested the same running lab (method).
| Strategy | Verdict | Result | Checks that failed |
|---|---|---|---|
| Ping only | safe | ✅ | none |
| All BGP sessions up | safe | ✅ | none |
| Netdryrun intent checks | safe | ✅ | none |
What Netdryrun flagged¶
Nothing: every check in the intent spec passed, so Netdryrun called the change safe.
Reproduce it¶
On Linux or WSL2 with Docker and containerlab, from a checkout of the repository:
Case file: corpus/cases/07-tighten-max-prefix.yml. Published result: netdryrun 0.2.0, containerlab 0.81.1, FRR quay.io/frrouting/frr:10.4.1, commit ec23379, run on 2026-10-26.