Scenario
You are using nginx and trying to call the downstream application but it returns http 502.
Cause
The reason could be because SELINUX would have blocked certain port. You can check the logs for more details.
Steps
The following example is from a sample repo whereby the downstream application uses port 801 and 802.
- Check the ngnix logs — /var/log/ngnix/error.log
From here you will be able to see the error “permission denied”
2. Check the audit log — /var/log/audit/audit.log
Command:
sudo cat /var/log/audit/audit.log | grep nginx | grep denied
Steps
- Navigate to the network interface in EC2 as below.
a. Search for the IP address, click on flow logs and destination name.
b. Take note of the Network interface ID (eni-xxxxxxx) which you would need in Step 2.
2. On the CloudWatch page, look for the log stream related to the Network interface ID.
Steps
- Stop Windows Update Services → (Go to run → services.msc → Windows Update)
2. Ensure Firewall is running, else start the Windows Firewall services (Go to run → Services.msc → Windows Firewall)
