Hello everyone,
I am currently facing an issue where API communication between internal systems and external services is being blocked intermittently after network/security configuration changes.
Our internal application needs to connect with external endpoints for data exchange. But requests are either failing or getting blocked without a clear error response.
This issue is impacting our workflow operations in a production environment used within Avenue Billing Services, where real-time data exchange is required for processing tasks.
What has been observed so far:
API requests work sometimes but fail intermittently
No consistent error message returned from endpoint
HTTPS (port 443) traffic seems affected
Internal services work fine without external calls
Issue started after recent firewall policy updates
Possible observations:
Firewall rule restrictions on outbound traffic
NAT or routing misconfiguration
IPS/IDS blocking specific request patterns
SSL inspection interfering with API calls
DNS resolution inconsistencies under VPN/network policy
Questions:
What would be the best approach to troubleshoot this in a Cisco-managed environment?
Should I primarily check:
Access Control Lists (ACLs)
Firewall logging and dropped packet analysis
NAT configuration
Security policy inspection rules
Any guidance on structured troubleshooting steps would be really helpful.
Thanks in advance.
