Minimum Version Required: 26.01
Pre-Conditions
Network Access: Requires access to network diagnostic tools (e.g.,
ping,telnet,nslookup,traceroute).Permissions: Logged in as an administrator or requiring sufficient privileges to view and modify firewall rules, cloud Security Groups, and DNS settings.
System Visibility: Requires access to server application logs, load balancer configurations, and TLS proxy gateways.
Steps
Check Service Status: Verify that the downstream service is online and ensure it is not crashing or actively restarting.
Verify Port Listening: Confirm that the target host or the specified port is actively listening for incoming traffic.
Review Network Security: Inspect local firewall rules and cloud Security Groups to ensure they are not inadvertently blocking incoming or outgoing packets.
Validate DNS Records: Perform a DNS resolution check to ensure traffic is not being pointed to an incorrect or stale endpoint IP address.
Inspect Gateway Endpoints: Check your TLS proxy or load balancer gateway to confirm there is no endpoint mismatch preventing the connection.
Contact Support: If the issue persists after attempting the steps above, please contact support. Gather and provide the following information for efficient troubleshooting:
Exact error messages or codes encountered.
Screenshots or video recordings of the issue.
Log files (specifically server logs, firewall network traces, and load balancer logs).
The exact steps taken by the customer that led to the issue.
The date and time the issue was first observed and any recurrence.
Any changes made to the system before the issue appeared.
Fields And Definitions
Target Host: The specific server or machine that the network traffic is intended to reach.
Port: A specific, logical endpoint on a host that is designated to receive incoming traffic.
Security Groups: Cloud-based virtual firewalls that control inbound and outbound network traffic at the instance level.
Downstream Service: An application or microservice that receives requests from a primary or upstream component.
DNS Resolution: The process of translating a domain name into its corresponding endpoint IP address.
TLS Proxy: A server that sits between the client and target server, managing encryption and routing of traffic.
Load Balancer Gateway: A network device or service that distributes incoming traffic across multiple servers to ensure reliability and performance.
Best Practices
Active Monitoring: Implement continuous health monitoring and alerting on downstream services to immediately detect crashes or offline statuses.
DNS TTL Management: Keep Time-To-Live (TTL) values reasonably low for critical services to ensure fast propagation if endpoints change, preventing traffic from hitting stale IPs.
Regular Firewall Audits: Periodically review firewall rules and cloud Security Groups to ensure valid ports are open and redundant or conflicting rules are removed.
Automated Load Balancer Health Checks: Configure your load balancer to automatically drop unresponsive endpoints from the pool to avoid routing traffic to offline targets.