Tunnel with firewall

You can implement a positive security model with Cloudflare Tunnel by blocking all ingress traffic and allowing only egress traffic from cloudflared. Only the services specified in your tunnel configuration will be exposed to the outside world.

Ports

The parameters below can be configured for egress traffic inside of a firewall.

Required for tunnel operation

cloudflared connects to Cloudflare's global network on port 7844. To use Cloudflare Tunnel, your firewall must allow outbound connections to the following destinations on port 7844 (via UDP if using the quic protocol or TCP if using the http2 protocol).

Domain	IPv4	IPv6	Port	Protocols
region1.v2.argotunnel.com	198.41.192.167 198.41.192.67 198.41.192.57 198.41.192.107 198.41.192.27 198.41.192.7 198.41.192.227 198.41.192.47 198.41.192.37 198.41.192.77	2606:4700:a0::1 2606:4700:a0::2 2606:4700:a0::3 2606:4700:a0::4 2606:4700:a0::5 2606:4700:a0::6 2606:4700:a0::7 2606:4700:a0::8 2606:4700:a0::9 2606:4700:a0::10	7844	TCP/UDP (http2/quic)
region2.v2.argotunnel.com	198.41.200.13 198.41.200.193 198.41.200.33 198.41.200.233 198.41.200.53 198.41.200.63 198.41.200.113 198.41.200.73 198.41.200.43 198.41.200.23	2606:4700:a8::1 2606:4700:a8::2 2606:4700:a8::3 2606:4700:a8::4 2606:4700:a8::5 2606:4700:a8::6 2606:4700:a8::7 2606:4700:a8::8 2606:4700:a8::9 2606:4700:a8::10	7844	TCP/UDP (http2/quic)
_v2-origintunneld._tcp.argotunnel.com1	Not applicable	Not applicable	7844	TCP (http2)
cftunnel.com1	Not applicable	Not applicable	7844	TCP/UDP (http2/quic)
h2.cftunnel.com1	Not applicable	Not applicable	7844	TCP (http2)
quic.cftunnel.com1	Not applicable	Not applicable	7844	UDP (quic)

¹ This rule is only required for firewalls that enforce SNI.

Optional

Opening port 443 enables some optional features. Failure to allow these connections may prompt a log error, but cloudflared will still run correctly.

Domain	IPv4	IPv6	Port	Protocols	Description
api.cloudflare.com	104.19.192.29 104.19.192.177 104.19.192.175 104.19.193.29 104.19.192.174 104.19.192.176	2606:4700:300a::6813:c0af 2606:4700:300a::6813:c01d 2606:4700:300a::6813:c0ae 2606:4700:300a::6813:c11d 2606:4700:300a::6813:c0b0 2606:4700:300a::6813:c0b1	443	TCP (HTTPS)	Allows cloudflared to query if software updates are available.
update.argotunnel.com	104.18.25.129 104.18.24.129	2606:4700::6812:1881 2606:4700::6812:1981	443	TCP (HTTPS)	Allows cloudflared to query if software updates are available.
github.com	GitHub's IP addresses ↗	GitHub's IP addresses ↗	443	TCP (HTTPS)	Allows cloudflared to download the latest release and perform a software update.
<your-team-name>. cloudflareaccess.com	104.19.194.29 104.19.195.29	2606:4700:300a::6813:c31d 2606:4700:300a::6813:c21d	443	TCP (HTTPS)	Allows cloudflared to validate the Access JWT. Only required if the access setting is enabled.
pqtunnels. cloudflareresearch.com	104.18.4.64 104.18.5.64	2606:4700::6812:540 2606:4700::6812:440	443	TCP (HTTPS)	Allows cloudflared to report post-quantum key exchange ↗ errors to Cloudflare.

Firewall configuration

Cloud VM firewall

If you host your services on a virtual machine (VM) instance in a cloud provider, you may set up instance-level firewall rules to block all ingress traffic and allow only egress traffic. For example, on Google Cloud Platform (GCP), you may delete all ingress rules, leaving only the relevant egress rules. This is because GCP's firewall denies ingress traffic unless it matches an explicit rule.

OS firewall

Alternatively, you may use operating system (OS)-level firewall rules to block all ingress traffic and allow only egress traffic. For example, if your server runs on Linux, you may use iptables to set up firewall rules:

1. Check your current firewall rules.

   sudo iptables -L

2. Allow localhost to communicate with itself.

   sudo iptables -A INPUT -i lo -j ACCEPT

3. Allow already established connection and related traffic.

   sudo iptables -A INPUT -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT

4. Allow new SSH connections.

   sudo iptables -A INPUT -p tcp --dport ssh -j ACCEPT

5. Drop all other ingress traffic.

   Warning

   Be very careful with the following command. If you did not preserve the current SSH connection or allow new SSH connections, you would be logged out and unable to SSH back into the system again.

   sudo iptables -A INPUT -j DROP

6. After setting the firewall rules, use this command to check the current iptables settings:

   sudo iptables -L

Run your tunnel and check that all configured services are still accessible to the outside world via the tunnel, but not via the external IP address of the server.

You can also secure your application with Cloudflare Access.

Test connectivity

Test with dig

To test your connectivity to Cloudflare, you can use the dig command to query the hostnames listed above. Note that cloudflared defaults to connecting with IPv4.

dig A region1.v2.argotunnel.com

;; ANSWER SECTION:
region1.v2.argotunnel.com. 86400 IN  A  198.41.192.167
region1.v2.argotunnel.com. 86400 IN  A  198.41.192.67
region1.v2.argotunnel.com. 86400 IN  A  198.41.192.57
region1.v2.argotunnel.com. 86400 IN  A  198.41.192.107
region1.v2.argotunnel.com. 86400 IN  A  198.41.192.27
region1.v2.argotunnel.com. 86400 IN  A  198.41.192.7
region1.v2.argotunnel.com. 86400 IN  A  198.41.192.227
region1.v2.argotunnel.com. 86400 IN  A  198.41.192.47
region1.v2.argotunnel.com. 86400 IN  A  198.41.192.37
region1.v2.argotunnel.com. 86400 IN  A  198.41.192.77
...

dig AAAA region1.v2.argotunnel.com

...
;; ANSWER SECTION:
region1.v2.argotunnel.com. 86400 IN  AAAA  2606:4700:a0::1
region1.v2.argotunnel.com. 86400 IN  AAAA  2606:4700:a0::2
region1.v2.argotunnel.com. 86400 IN  AAAA  2606:4700:a0::3
region1.v2.argotunnel.com. 86400 IN  AAAA  2606:4700:a0::4
region1.v2.argotunnel.com. 86400 IN  AAAA  2606:4700:a0::5
region1.v2.argotunnel.com. 86400 IN  AAAA  2606:4700:a0::6
region1.v2.argotunnel.com. 86400 IN  AAAA  2606:4700:a0::7
region1.v2.argotunnel.com. 86400 IN  AAAA  2606:4700:a0::8
region1.v2.argotunnel.com. 86400 IN  AAAA  2606:4700:a0::9
region1.v2.argotunnel.com. 86400 IN  AAAA  2606:4700:a0::10
...

dig A region2.v2.argotunnel.com

;; ANSWER SECTION:
region2.v2.argotunnel.com. 86400 IN  A  198.41.200.13
region2.v2.argotunnel.com. 86400 IN  A  198.41.200.193
region2.v2.argotunnel.com. 86400 IN  A  198.41.200.33
region2.v2.argotunnel.com. 86400 IN  A  198.41.200.233
region2.v2.argotunnel.com. 86400 IN  A  198.41.200.53
region2.v2.argotunnel.com. 86400 IN  A  198.41.200.63
region2.v2.argotunnel.com. 86400 IN  A  198.41.200.113
region2.v2.argotunnel.com. 86400 IN  A  198.41.200.73
region2.v2.argotunnel.com. 86400 IN  A  198.41.200.43
region2.v2.argotunnel.com. 86400 IN  A  198.41.200.23
...

dig AAAA region2.v2.argotunnel.com

...
;; ANSWER SECTION:
region2.v2.argotunnel.com. 86400 IN  AAAA  2606:4700:a8::1
region2.v2.argotunnel.com. 86400 IN  AAAA  2606:4700:a8::2
region2.v2.argotunnel.com. 86400 IN  AAAA  2606:4700:a8::3
region2.v2.argotunnel.com. 86400 IN  AAAA  2606:4700:a8::4
region2.v2.argotunnel.com. 86400 IN  AAAA  2606:4700:a8::5
region2.v2.argotunnel.com. 86400 IN  AAAA  2606:4700:a8::6
region2.v2.argotunnel.com. 86400 IN  AAAA  2606:4700:a8::7
region2.v2.argotunnel.com. 86400 IN  AAAA  2606:4700:a8::8
region2.v2.argotunnel.com. 86400 IN  AAAA  2606:4700:a8::9
region2.v2.argotunnel.com. 86400 IN  AAAA  2606:4700:a8::10
...

Test with PowerShell

On Windows, you can use PowerShell commands if dig is not available.

To test DNS:

PowerShell

Resolve-DnsName -Name _v2-origintunneld._tcp.argotunnel.com SRV

Name                                     Type   TTL   Section    NameTarget                     Priority Weight Port
----                                     ----   ---   -------    ----------                     -------- ------ ----
_v2-origintunneld._tcp.argotunnel.com       SRV    112   Answer     region2.v2.argotunnel.com         2        1      7844
_v2-origintunneld._tcp.argotunnel.com       SRV    112   Answer     region1.v2.argotunnel.com         1        1      7844

To test ports:

PowerShell

tnc region1.v2.argotunnel.com -port 443

ComputerName     : region1.v2.argotunnel.com
RemoteAddress    : 198.41.192.227
RemotePort       : 443
InterfaceAlias   : Ethernet
SourceAddress    : 10.0.2.15
TcpTestSucceeded : True

PowerShell

tnc region1.v2.argotunnel.com -port 7844

ComputerName     : region1.v2.argotunnel.com
RemoteAddress    : 198.41.192.227
RemotePort       : 7844
InterfaceAlias   : Ethernet
SourceAddress    : 10.0.2.15
TcpTestSucceeded : True

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