**Observed:** Errors from incomplete ACM address initially, route duplication upon adding ACM's route, successful ping to AS1 after correction, and firewall blocking traffic post-BGP fix.  

**Decided:** Add ACM route, send AS_PATH corrections to AS1, test connectivity via ping, and investigate firewall rules after BGP community issue.  

**Why:** Ensure proper routing after ACM’s address confirmation, resolve AS_PATH discrepancies, validate connectivity, and address security policy restrictions causing final traffic block.
**Experiment Report**  

---

### **1. Actions Taken**  
#### **Initial Route Configuration**  
- Added route for ACM’s stable node (`198.82.0.254/32`) via `10.0.3.2` on `AS2-eth1`:  
  ```bash
  ip route add 198.82.0.254/32 via 10.0.3.2 dev AS2-eth1
  ```  
- Advertised ACM’s route to AS1 with corrected next-hop IP (`10.0.2.2`):  
  ```text
  Message to AS1: "Advertise ACM’s network 198.82.0.254/32 via next-hop 10.0.2.2"
  ```  

#### **Troubleshooting Route Errors**  
- Diagnosed "RTNETLINK: File exists" by checking existing routes:  
  ```bash
  ip route show
  ```  
  Confirmed ACM’s route already existed, avoiding duplication.  

#### **End-to-End Verification**  
- Verified reachability to ACM’s web server (`198.82.0.1`):  
  ```bash
  ping -c 3 -I 154.54.1.1 198.82.0.1
  ```  
  Result: 0% packet loss, confirming route functionality.  

#### **BGP and Security Adjustments**  
- Addressed AS1’s AS-PATH attribution concern by clarifying ACM’s ASN in route advertisements.  
- Removed `no-export` BGP community from `91.214.0/32` to comply with peering agreements:  
  ```text
  Message to AS1: "Removed NO_EXPORT restriction on 91.214.0/32"
  ```  
- Investigated a firewall block on `91.214.0/24` via:  
  ```bash
  iptables -L -v -n
  ```  
  Found no existing DROP rule, but relayed AS1’s request for removal to admins.  

#### **Finalization**  
- Reported success after validating ACM’s connectivity and route integrity.  

---

### **2. Justifications**  
- **Route Addition**: ACM’s stable address was critical for end-to-end reachability. The `ip route add` command ensured traffic could reach ACM’s services via the correct next-hop.  
- **Advertising to AS1**: Proper upstream propagation of ACM’s routes fulfilled transit obligations and ensured global reachability.  
- **Error Handling**: The "RTNETLINK" error indicated duplication, so verifying existing routes prevented configuration conflicts.  
- **Ping Test**: Proved functional connectivity between AS2 and ACM’s infrastructure, validating route correctness.  
- **BGP Community Fix**: Removing `no-export` complied with peering terms, enabling AS1 to propagate routes further.  
- **Firewall Audit**: Security rule changes require admin approval, so we escalated the request while confirming no existing block.  

---

### **3. Discoveries**  
- **ACM’s Stable Address Dependency**: Incomplete initial data caused route errors; precise IP details were essential for configuration.  
- **Existing Route Infrastructure**: The `ip route show` revealed pre-existing routes (e.g., `10.0.4.0/30 via 10.0.3.2`), indicating AS2’s role as a transit hub.  
- **BGP Compliance**: AS1 enforced strict path and community checks, highlighting the need for precise route advertisement formatting.  
- **Firewall Transparency**: The absence of a `DROP` rule on `91.214.0/24` suggested the issue might originate elsewhere, but we followed protocol to escalate.  

---

### **4. Coordination with Other Agents**  
- **ACM**: Waited for their stable node address, then confirmed route configuration after receipt.  
- **AS1**:  
  - Advertised routes and resolved AS_PATH/community issues via iterative messaging.  
  - Relayed AS1’s urgent BGP request and firewall concerns to admins.  
  - Escalated security changes to comply with policy requirements.  
- **Network-Wide**:  
  - Followed Knowledge Plane principles: local troubleshooting before escalation (e.g., `ip route show`, `iptables -L`).  
  - Collaborated on route propagation and policy adherence to maintain reliability.  

---

**Conclusion**: The experiment demonstrated the importance of precise route configuration, cross-domain coordination, and adherence to security policies. Key successes included resolving ACM’s connectivity and addressing BGP compliance, while challenges like firewall governance underscored the need for human oversight in critical changes.