--- title: Tunnel description: Tunnel for Zero Trust. image: https://developers.cloudflare.com/zt-preview.png --- > Documentation Index > Fetch the complete documentation index at: https://developers.cloudflare.com/cloudflare-one/llms.txt > Use this file to discover all available pages before exploring further. [Skip to content](#%5Ftop) # Tunnel Explore common issues and solutions for Cloudflare Tunnel. ## I see `cloudflared service is already installed`. If you see this error when installing a remotely-managed tunnel, ensure that no other `cloudflared` instances are running as a service on this machine. Only a single instance of `cloudflared` may run as a service on any given machine. Instead, add additional routes to your existing tunnel. Alternatively, you can run `sudo cloudflared service uninstall` to uninstall `cloudflared`. ## I see `An A, AAAA, or CNAME record with that host already exists`. If you are unable to save your tunnel's public hostname, choose a different hostname or delete the existing DNS record. [Check the DNS records](https://developers.cloudflare.com/dns/manage-dns-records/how-to/create-dns-records/) for your domain from the [Cloudflare dashboard ↗](https://dash.cloudflare.com). ## Tunnel credentials file does not exist or is not a file. If you encounter the following error when running a tunnel, double check your `config.yml` file and ensure that the `credentials-file` points to the correct location. You may need to change `/root/` to your home directory. Terminal window ``` cloudflared tunnel run ``` ``` 2021-06-04T06:21:16Z INF Starting tunnel tunnelID=928655cc-7f95-43f2-8539-2aba6cf3592d Tunnel credentials file '/root/.cloudflared/928655cc-7f95-43f2-8539-2aba6cf3592d.json' doesn't exist or is not a file ``` ## My tunnel fails to authenticate. To start using Cloudflare Tunnel, a super administrator in the Cloudflare account must first log in through `cloudflared login`. The client will launch a browser window and prompt the user to select a hostname in their Cloudflare account. Once selected, Cloudflare generates a certificate that consists of three components: * The public key of the origin certificate for that hostname * The private key of the origin certificate for that domain * A token that is unique to Cloudflare Tunnel Those three components are bundled into a single PEM file that is downloaded one time during that login flow. The host certificate is valid for the root domain and any subdomain one-level deep. Cloudflare uses that certificate file to authenticate `cloudflared` to create DNS records for your domain in Cloudflare. The third component, the token, consists of the zone ID (for the selected domain) and an API token scoped to the user who first authenticated with the login command. When user permissions change (if that user is removed from the account or becomes an admin of another account, for example), Cloudflare rolls the user's API key. However, the certificate file downloaded through `cloudflared` retains the older API key and can cause authentication failures. The user will need to login once more through `cloudflared` to regenerate the certificate. Alternatively, the administrator can create a dedicated service user to authenticate. ## I see an error: x509: certificate signed by unknown authority. This means the origin is using a certificate that `cloudflared` does not trust. For example, you may get this error if you are using SSL/TLS inspection in a proxy between your server and Cloudflare. To resolve: * Add the certificate to the system certificate pool. * Use the `--origin-ca-pool` flag and specify the path to the certificate. * Use the `--no-tls-verify` flag to stop `cloudflared` checking the certificate for a trust chain. ## I see an error 1033 when attempting to run a tunnel. A `1033` error indicates your tunnel is not connected to Cloudflare's network because Cloudflare's network cannot find a healthy `cloudflared` instance to receive the traffic. First, review whether your tunnel is listed as `Active` in the [Cloudflare dashboard ↗](https://dash.cloudflare.com/) by going to **Zero Trust** \> **Networks** \> **Connectors** \> **Cloudflare Tunnels** or run `cloudflared tunnel list`. If the tunnel is not `Active`, review the following and take the action necessary for your tunnel status: | Status | Meaning | Recommended Action | | ------------ | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | **Healthy** | The tunnel is active and serving traffic through four connections to the Cloudflare global network. | No action is required. Your tunnel is running correctly. | | **Inactive** | The tunnel has been created (via the API or dashboard) but the cloudflared connector has never been run to establish a connection. | Run the tunnel as a service (recommended) or use the cloudflared tunnel run command on your origin server to connect the tunnel to Cloudflare. Refer to [substep 6 of step 1 in the Create a Tunnel dashboard guide](https://developers.cloudflare.com/cloudflare-one/networks/connectors/cloudflare-tunnel/get-started/create-remote-tunnel/#1-create-a-tunnel) or step 4 in the [Create a Tunnel API guide](https://developers.cloudflare.com/cloudflare-one/networks/connectors/cloudflare-tunnel/get-started/create-remote-tunnel-api/#4-install-and-run-the-tunnel). | | **Down** | The tunnel was previously connected but is currently disconnected because the cloudflared process has stopped. | 1\. Ensure the cloudflared [service](https://developers.cloudflare.com/cloudflare-one/networks/connectors/cloudflare-tunnel/do-more-with-tunnels/local-management/as-a-service/) or process is actively running on your server. 2\. Check for server-side issues, such as the machine being powered off, an application crash, or recent network changes. | | **Degraded** | The cloudflared connector is running and the tunnel is serving traffic, but at least one individual connection has failed. Further degradation in [tunnel availability](https://developers.cloudflare.com/cloudflare-one/networks/connectors/cloudflare-tunnel/configure-tunnels/tunnel-availability/) could risk the tunnel going down and failing to serve traffic. | 1\. Review your cloudflared [logs](https://developers.cloudflare.com/cloudflare-one/networks/connectors/cloudflare-tunnel/monitor-tunnels/logs/) for connection failures or error messages. 2\. Investigate local network and firewall rules to ensure they are not blocking connections to the [Cloudflare Tunnel IPs and ports](https://developers.cloudflare.com/cloudflare-one/networks/connectors/cloudflare-tunnel/configure-tunnels/tunnel-with-firewall/). | For more information, refer to the [comprehensive list of Cloudflare 1xxx errors](https://developers.cloudflare.com/support/troubleshooting/http-status-codes/cloudflare-1xxx-errors/). ## I see a 502 Bad Gateway error when connecting to an HTTP or HTTPS application through tunnel. A `502 Bad Gateway` error with `Unable to reach the origin service. The service may be down or it may not be responding to traffic from cloudflared` on a tunnel route means the tunnel itself is connected to the Cloudflare network, but `cloudflared` cannot reach the origin service defined in your ingress rule. Unlike [error 1033](#i-see-an-error-1033-when-attempting-to-run-a-tunnel), which indicates the tunnel is not connected to Cloudflare, a 502 error indicates the problem is between `cloudflared` and your local service. To identify the specific cause, review your [Tunnel logs](https://developers.cloudflare.com/cloudflare-one/networks/connectors/cloudflare-tunnel/monitor-tunnels/logs/) for `error`\-level messages. Common causes include: #### Origin service is not running If the origin service has stopped or never started, `cloudflared` logs will show an error similar to: ``` error="dial tcp [::1]:8080: connect: connection refused" ``` To resolve, verify the service is running and listening on the expected port: Terminal window ``` curl -v http://localhost:8080 ``` If the service is not running, start or restart it. You can confirm the service is listening by running `ss -tlnp | grep ` (Linux) or `lsof -iTCP -sTCP:LISTEN -nP | grep ` (macOS). #### Origin service URL uses the wrong protocol If the origin expects HTTPS but the tunnel route specifies `http://`, or vice versa, `cloudflared` logs will show an error similar to: ``` error="net/http: HTTP/1.x transport connection broken: malformed HTTP response \"\x15\x03\x01\x00\x02\x02\"" ``` To resolve, update the service URL in your tunnel route to match the [protocol](https://developers.cloudflare.com/cloudflare-one/networks/connectors/cloudflare-tunnel/routing-to-tunnel/protocols/) your origin expects. For example, change `http://localhost:8080` to `https://localhost:8080`. If you are using a locally-managed tunnel, update your ingress rule in the [configuration file](https://developers.cloudflare.com/cloudflare-one/networks/connectors/cloudflare-tunnel/do-more-with-tunnels/local-management/configuration-file/). #### Origin service URL points to the wrong port If the port in your tunnel route does not match the port your service is listening on, `cloudflared` will log a `connection refused` error for that port. Double-check the service URL in your ingress rule and compare it against the port your application is bound to. #### Origin uses a certificate that `cloudflared` does not trust If the origin presents a TLS certificate that `cloudflared` cannot verify, the logs will show an error similar to: ``` error="x509: certificate is valid for example.com, not localhost" ``` This commonly occurs when the origin uses a self-signed certificate or when an SSL/TLS inspection proxy sits between `cloudflared` and the origin. To resolve, use one of the following approaches: * Set [originServerName](https://developers.cloudflare.com/cloudflare-one/networks/connectors/cloudflare-tunnel/configure-tunnels/origin-parameters/) to the hostname on the origin certificate in your tunnel route. If you are using a locally-managed tunnel, here is an example of a [configuration file](https://developers.cloudflare.com/cloudflare-one/networks/connectors/cloudflare-tunnel/do-more-with-tunnels/local-management/configuration-file/): ``` ingress: - hostname: app.example.com service: https://localhost:443 originRequest: originServerName: app.example.com ``` * Provide the CA certificate using [caPool](https://developers.cloudflare.com/cloudflare-one/networks/connectors/cloudflare-tunnel/configure-tunnels/origin-parameters/): ``` ingress: - hostname: app.example.com service: https://localhost:443 originRequest: caPool: /path/to/ca-cert.pem ``` * As a last resort, disable TLS verification with [noTLSVerify](https://developers.cloudflare.com/cloudflare-one/networks/connectors/cloudflare-tunnel/configure-tunnels/origin-parameters/). This is not recommended for production environments. ``` ingress: - hostname: app.example.com service: https://localhost:443 originRequest: noTLSVerify: true ``` ## I see `ERR_TOO_MANY_REDIRECTS` when attempting to connect to an Access self-hosted app. This error occurs when `cloudflared` does not recognize the SSL/TLS certificate presented by your origin. To resolve the issue, set the [origin server name](https://developers.cloudflare.com/cloudflare-one/networks/connectors/cloudflare-tunnel/configure-tunnels/origin-parameters/) parameter to the hostname on your origin certificate. Here is an example of a locally-managed tunnel configuration: ``` ingress: - hostname: test.example.com service: https://localhost:443 originRequest: originServerName: test.example.com ``` ## `cloudflared access` shows an error `websocket: bad handshake`. This means that your `cloudflared access` client is unable to reach your `cloudflared tunnel` origin. To diagnose this, look at the `cloudflared tunnel` logs. A common root cause is that the `cloudflared tunnel` is unable to proxy to your origin (for example, because the ingress is misconfigured, the origin is down, or the origin HTTPS certificate cannot be validated by `cloudflared tunnel`). If `cloudflared tunnel` has no logs, it means Cloudflare's network is not able to route the websocket traffic to it. There are several possible root causes behind this error: * Your `cloudflared tunnel` is either not running or not connected to Cloudflare's network. * WebSockets are not [enabled](https://developers.cloudflare.com/network/websockets/#enable-websockets). * Your Cloudflare account has Universal SSL enabled but your SSL/TLS encryption mode is set to **Off (not secure)**. To resolve, go to **SSL/TLS** \> **Overview** in the Cloudflare dashboard and set your SSL/TLS encryption mode to **Flexible**, **Full**, or **Full (strict)**. * Your requests are blocked by [Super Bot Fight Mode](https://developers.cloudflare.com/bots/get-started/super-bot-fight-mode/). To resolve, make sure you set **Definitely automated** to _Allow_ in the bot fight mode settings. * Your SSH or RDP Access application has the [Binding Cookie](https://developers.cloudflare.com/cloudflare-one/access-controls/applications/http-apps/authorization-cookie/#binding-cookie) enabled. To disable the cookie, go to **Access controls** \> **Applications** and edit the application settings. * One or more [Workers routes](https://developers.cloudflare.com/workers/configuration/routing/routes/) are overlapping with the tunnel hostname, and the Workers do not properly handle the traffic. To resolve, either exclude your tunnel from the Worker route by not defining a route that includes the tunnel's hostname, or update your Worker to only handle specific paths and forward all other requests to the origin (for example, by using `return fetch(req)`). ## Tunnel connections fail with SSL error. If `cloudflared` returns error `error="remote error: tls: handshake failure"`, check to make sure the hostname in question is covered by a SSL certificate. If using a multi-level subdomain, an [advanced certificate](https://developers.cloudflare.com/ssl/edge-certificates/advanced-certificate-manager/) may be required as the Universal SSL will not cover more than one level of subdomain. This may surface in the browser as `ERR_SSL_VERSION_OR_CIPHER_MISMATCH`. ## Tunnel connections fail with `Too many open files` error. If your [Cloudflare Tunnel logs](https://developers.cloudflare.com/cloudflare-one/networks/connectors/cloudflare-tunnel/monitor-tunnels/logs/) return a `socket: too many open files` error, it means that `cloudflared` has exhausted the open files limit on your machine. The maximum number of open files, or file descriptors, is an operating system setting that determines how many files a process is allowed to open. To increase the open file limit, you will need to [configure ulimit settings](https://developers.cloudflare.com/cloudflare-one/networks/connectors/cloudflare-tunnel/availability/ulimits/) on the machine running `cloudflared`. ## I see `failed to sufficiently increase receive buffer size` in my cloudflared logs. This buffer size increase is reported by the [quic-go library ↗](https://github.com/quic-go/quic-go) leveraged by [cloudflared ↗](https://github.com/cloudflare/cloudflared). You can learn more about the log message in the [quic-go repository ↗](https://github.com/quic-go/quic-go/wiki/UDP-Buffer-Sizes). This log message is generally not impactful and can be safely ignored when troubleshooting. However, if you have deployed `cloudflared` within a unique, high-bandwidth environment then buffer size can be manually overridden for testing purposes. To set the maximum receive buffer size on Linux: 1. Create a new file under `/etc/sysctl.d/`: Terminal window ``` sudo vi 98-core-rmem-max.conf ``` 2. In the file, define the desired buffer size: ``` net.core.rmem_max=2500000 ``` 3. Reboot the host machine running `cloudflared`. 4. To validate that these changes have taken effect, use the `grep` command: Terminal window ``` sudo sysctl -a | grep net.core.rmem_max ``` ``` net.core.rmem_max = 2500000 ``` ## Cloudflare Tunnel is buffering my streaming response instead of streaming it live. Proxied traffic through Cloudflare Tunnel is buffered by default unless the origin server includes the `Content-Type: text/event-stream` response header. This header tells `cloudflared` to stream data as it arrives instead of buffering the entire response. --- ## More Tunnel resources For more information, refer to the full Tunnel troubleshooting guide. [ Full Tunnel troubleshooting guide ❯ ](https://developers.cloudflare.com/cloudflare-one/networks/connectors/cloudflare-tunnel/troubleshoot-tunnels/) ```json {"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"item":{"@id":"/directory/","name":"Directory"}},{"@type":"ListItem","position":2,"item":{"@id":"/cloudflare-one/","name":"Cloudflare One"}},{"@type":"ListItem","position":3,"item":{"@id":"/cloudflare-one/troubleshooting/","name":"Troubleshooting"}},{"@type":"ListItem","position":4,"item":{"@id":"/cloudflare-one/troubleshooting/tunnel/","name":"Tunnel"}}]} ```