@itlandytech: It pings, so the network is fine it must be an application issue! Every network engineer or system administrator has heard this at least once. While a successful ICMP ping confirms basic layer 3 IP connectivity, it tells you almost nothing about whether your web app, database, or RDP session will actually connect. Here is a 6-step practical troubleshooting flow to isolate and fix the issue when Ping Works, But the Application Doesn't: 1. Check IP Connectivity Start with ping . If it succeeds, basic routing works. If it fails, verify IP settings, VLANs, gateways, and basic physical link status. 2. Check Application Port Reachability Test if the target transport port is actually open across the network: * telnet * PowerShell: Test-NetConnection -Port * If blocked: Review firewall rules, security groups, and ACLs along the path. 3. Verify the Application Service Status Confirm the application service is running and listening on the server side: * Windows: Get-Service -Name or netstat -an | find "" * If not listening: Start or restart the required service (IIS, SQL, RDP, etc.). 4. Check DNS & Name Resolution If users connect using a hostname instead of an IP address, verify DNS: * nslookup app.company.com * If failing: Flush local DNS cache, check DNS server settings, or verify A/AAAA records. 5. Test the Application Layer (Protocol) Validate that the protocol returns an expected response: * curl -I http:// * If failing: Check credentials, web server permissions, SSL/TLS certificates, or application logs. 6. Inspect End-to-End Security Policies Deep packet inspection, proxies, or Next-Gen Firewalls (NGFW) might be silently dropping application traffic. Check IPS logs, proxy configurations, and NAT/segmentation rules. Save this workflow for your next late-night outage! What’s your go-to command when an app is down? Let me know in the comments. #NetworkEngineering #SysAdmin #ITInfrastructure #Troubleshooting #DevOps

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Wednesday 30 September 2026 18:22:15 GMT