Host Connection Diagnostic Report

Proven

Pattern 1: Stable Configuration

The original stable connection. We used DNS Name for Base24 and Fixed IP for the Passbook host (AIX).
graph LR ATM["ATM Terminal"] Base24["Base24 Host"] Passbook["AIX (Passbook)"] ATM -- "DNS Name" --> Base24 ATM -- "IP Address" --> Passbook style ATM fill:#1a1a1a,color:#fff,stroke:#000 style Base24 fill:#f5f5f5,color:#000,stroke:#333 style Passbook fill:#f5f5f5,color:#000,stroke:#333
Upgrade

Pattern 2: The DNS Migration

Project goal: Migrate all connections to DNS Name and remove IP dependencies from the config.
graph LR ATM["ATM Terminal"] Base24["Base24 Host"] Passbook["AIX (Passbook)"] ATM -- "DNS Name" --> Base24 ATM -- "DNS Name (New)" --> Passbook style ATM fill:#1a1a1a,color:#fff,stroke:#000 style Base24 fill:#f5f5f5,color:#000,stroke:#333 style Passbook fill:#f5f5f5,color:#000,stroke:#333 linkStyle 1 stroke:#d32f2f,stroke-width:2px
Incident

Critical Software Fallback Bug

Analysis: Even with working DNS, the software (ATOM) fails over to Invalid IP addresses from the local config file after a Host Down event is detected.
graph TD ATM["ATM (Out of Service)"] Config["Local Config
(The Trap)"] Bank["Bank Hosts"] ATM -- "1. Host Down Event" --> Bank ATM -- "2. Software switches to IP" --> Config Config -- "3. Uses WRONG IPs" --> Bank style ATM fill:#d32f2f,color:#fff,stroke:#000 style Config fill:#1a1a1a,color:#fff,stroke-dasharray: 5 5 style Bank fill:#f5f5f5,color:#000,stroke:#333 linkStyle 1 stroke:#d32f2f,stroke-width:2px linkStyle 2 stroke:#d32f2f,stroke-width:2px

Invalid IPs Found in ATMCNFG.ini:

[TCPIPHostConfig]
IP01=10.0.0.2      // WRONG IP FOR BASE24
IP03=0.0.0.0       // INVALID IP FOR PASSBOOK
Cloud

Pattern 4: Migration from AIX to AKS

Modernization: The Passbook Host was moved from AIX to Azure Kubernetes Service (AKS).

Key Point: The OOS issue persists even on Cloud AKS, confirming that the host change is not the root cause.
graph LR ATM["ATM Terminal"] Base24["Base24 Host"] AKS["Cloud AKS
(New Passbook)"] ATM -- "DNS Name" --> Base24 ATM -- "DNS Name" --> AKS style ATM fill:#1a1a1a,color:#fff,stroke:#000 style Base24 fill:#f5f5f5,color:#000,stroke:#333 style AKS fill:#f5f5f5,color:#000,stroke:#333 linkStyle 1 stroke:#d32f2f,stroke-width:2px

Summary & Recommendation

The system fails because the software abandons healthy DNS resolution for incorrect hardcoded IPs.

Action Required: Fix the software logic to prioritize DNS or ensure the backup IPs in the config are correct.