Let’s work through some targeted checks to figure out why your new Elasticsearch instance isn’t reachable, even though your ELK connection is working:

1. Double-Check Your Port Forwarding Command #

First, let’s confirm the basics of your tunnel setup:

cf ssh my-logstash -L 9200:ES_HOST:443 -L 9201:ELK:59464 -i 0

• Make sure ES_HOST is the exact correct hostname or IP of your new Elasticsearch instance—typos here are super common.
• Verify the remote Elasticsearch is actually listening on port 443. Some setups use 9200 for HTTP or 9243 for HTTPS by default. Test this directly from the my-logstash instance by running:

  # Use telnet if available
  telnet ES_HOST 443
  # Or curl for more detail
  curl -v https://ES_HOST:443
  

2. Check for Local Port Conflicts #

Your local machine might have another service hogging port 9200, which blocks the tunnel. Check with these commands:

• On Linux/macOS:

  lsof -i :9200
  

• On Windows (PowerShell):

  netstat -ano | findstr ":9200"
  

If another process is using the port, either stop that process or adjust your tunnel to use a different local port (e.g., -L 9202:ES_HOST:443).

3. Validate SSL/TLS Configuration #

Since you’re connecting to port 443, Elasticsearch is likely using HTTPS. Test your local connection with SSL considerations:

• For quick testing, skip certificate verification temporarily with curl:

  curl -k https://localhost:9200
  

• If the cert is self-signed, you’ll need to import it into your local trust store, or configure your Elasticsearch client (like Logstash) to trust the certificate explicitly.

4. Confirm Network Access from my-logstash #

The my-logstash instance might not have permission to reach the new Elasticsearch host. SSH directly into my-logstash (without port forwarding) and run:

curl -v https://ES_HOST:443

If this fails, you’ll need to adjust firewall rules, security groups, or network policies to allow traffic from my-logstash to the new Elasticsearch instance on port 443.

5. Verify the SSH Tunnel is Active #

Sometimes tunnels drop silently without warning. Check if the cf ssh process is still running on your local machine, or reconnect with verbose output to debug tunnel issues:

cf ssh my-logstash -v -L 9200:ES_HOST:443 -L 9201:ELK:59464 -i 0

The verbose logs will show if there are problems establishing or maintaining the tunnel connection.

内容的提问来源于stack exchange，提问作者don ali