The Nitty Gritty Details

Tunnel Websocket Support

Argo Tunnel has full support for Websockets.

Using Tunnel with Partial DNS (CNAME Setup)

Cloudflare offers two modes of setup: Full Setup, in which the domain uses Cloudflare DNS name servers, and Partial Setup (also known as CNAME setup) in which the domain uses non-Cloudflare DNS servers.

The best experience with Tunnel is using Full Setup because Cloudflare manages DNS for the domain and can automatically configure DNS records for newly started Tunnels.

You can still use Tunnel with Partial Setup. What you will need to do is create a new DNS record with your current DNS provider for each new hostname you run Tunnel on. The DNS record should be of type CNAME or ALIAS if it is on the root of the domain. The name of the record should be the subdomain it corresponds to (e.g. or and the value of the record should be (e.g. or

Cleaning Up After Shutting Down Tunnel

Tunnel deletes DNS records after 24-48 hours of being unregistered. Tunnel does not delete TLS certificates on your behalf once the tunnel is shut down. If you want to clean up a tunnel you’ve shut down, you can delete DNS records in the DNS editor and revoke TLS certificates in the Origin Certificates section of the crypto tab of the Cloudflare dashboard.

Audit Logging

Audit Logs for Tunnel are available in the account section of the Cloudflare dashboard which you can find by clicking on your name or email in the upper right-hand corner of the dashboard. The following actions are logged:

Action Description
Registered This is logged when Tunnel is started and connects to the Cloudflare edge.
Unregistered This is logged when Tunnel is disconnected from the Cloudflare edge.
CNAME add This is logged when Tunnel registers a new DNS (CNAME) record for the tunneled application.

Securing the Origin Server

Tunnel can expose web applications to the internet that sit behind a NAT or firewall. Thus, you can keep your web server otherwise completely locked down. To double check that your origin web server is not responding to requests outside Cloudflare while Tunnel is running you can run netcat in the command line:

netcat -zv [your-server’s-ip-address] 80
netcat -zv [your-server’s-ip-address] 443

If your server is still responding on those ports, you will see:

[ip-address] 80 (http) open

If your server is correctly locked down, you will see:

[ip-address] 443 (https): Connection refused


Argo Tunnel was previously named Warp during the beta phase. As Warp was added to the Argo product family, we changed the name to match.

Maximum Number of Tunnels

Argo Tunnel allows a maximum number of 1000 concurrently running tunnels per account.