Set up a TLS listener

Documentation

Security

You can configure the SSE listener on the Agent Gateway with a TLS certificate to secure the communication to the Agent Gateway.

Download the .pem files for certificate and key that you use to secure the SSE listener.

curl -o cert.pem https://raw.githubusercontent.com/agentgateway/agentgateway/refs/heads/main/examples/tls/certs/cert.pem
curl -o key.pem https://raw.githubusercontent.com/agentgateway/agentgateway/refs/heads/main/examples/tls/certs/key.pem

Create a listener and target configuration for your Agent Gateway. In this example, the Agent Gateway is configured as follows:

Listener: An SSE listener is configured and exposed on port 3000. The listener is secured with the certificate and key that you downloaded earlier.
Target: The Agent Gateway targets a sample, open source MCP test server, server-everything.

cat <<EOF > config.json
{
  "type": "static",
  "listeners": [
    {
      "name": "sse",
      "protocol": "MCP",
      "sse": {
        "address": "[::]",
        "port": 3000,
        "tls": {
          "cert_pem": {
            "file_path": "./cert.pem"
          },
          "key_pem": {
            "file_path": "./key.pem"
          }
        }
      }
    }
  ],
  "targets": {
    "mcp": [
      {
        "name": "everything",
        "stdio": {
          "cmd": "npx",
          "args": [
            "@modelcontextprotocol/server-everything"
          ]
        }
      }
    ]
  }
}
EOF

Run the Agent Gateway.
```
agentgateway -f config.json
```

Send an HTTP request to the Agent Gateway. Verify that this request is denied and that you see a message that the HTTP protocol is not allowed.

curl -vik http://localhost:3000/sse

Example output:

curl -vik http://localhost:3000/sse             
...
> 
* Request completely sent off
* Received HTTP/0.9 when not allowed
* Closing connection
curl: (1) Received HTTP/0.9 when not allowed

Send an HTTPS request to the Agent Gateway. Verify that you see a TLS handshake and that a connection to the Agent Gateway can be established.

curl -vik https://localhost:3000/sse

Example output:

* Host localhost:3000 was resolved.
* IPv6: ::1
* IPv4: 127.0.0.1
*   Trying [::1]:3000...
* Connected to localhost (::1) port 3000
* ALPN: curl offers h2,http/1.1
* (304) (OUT), TLS handshake, Client hello (1):
* (304) (IN), TLS handshake, Server hello (2):
* (304) (IN), TLS handshake, Unknown (8):
* (304) (IN), TLS handshake, Certificate (11):
* (304) (IN), TLS handshake, CERT verify (15):
* (304) (IN), TLS handshake, Finished (20):
* (304) (OUT), TLS handshake, Finished (20):
* SSL connection using TLSv1.3 / AEAD-CHACHA20-POLY1305-SHA256 / [blank] / UNDEF
* ALPN: server accepted h2
* Server certificate:
*  subject: C=XX; ST=mass; L=boston; O=solo.io; OU=octo; CN=localhost
*  start date: Apr  9 19:18:58 2025 GMT
*  expire date: Apr  7 19:18:58 2035 GMT
*  issuer: C=XX; ST=mass; L=boston; O=solo.io; OU=octo; CN=localhost
*  SSL certificate verify result: self signed certificate (18), continuing anyway.
* using HTTP/2
* [HTTP/2] [1] OPENED stream for https://localhost:3000/sse
* [HTTP/2] [1] [:method: GET]
* [HTTP/2] [1] [:scheme: https]
* [HTTP/2] [1] [:authority: localhost:3000]
* [HTTP/2] [1] [:path: /sse]
* [HTTP/2] [1] [user-agent: curl/8.7.1]
* [HTTP/2] [1] [accept: */*]
> GET /sse HTTP/2
> Host: localhost:3000
> User-Agent: curl/8.7.1
> Accept: */*
> 
* Request completely sent off
< HTTP/2 200 
HTTP/2 200 
...

event: endpoint
data: ?sessionId=f25025b0f78d5a143ce43c36cedaebec

Authenticate requests