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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).

DomainIPv4IPv6PortProtocols
region1.v2.argotunnel.com198.41.192.167
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		7844TCP/UDP (http2/quic)
region2.v2.argotunnel.com198.41.200.13
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		7844TCP/UDP (http2/quic)
_v2-origintunneld._tcp.argotunnel.com1Not applicableNot applicable7844TCP (http2)
cftunnel.com1Not applicableNot applicable7844TCP/UDP (http2/quic)
h2.cftunnel.com1Not applicableNot applicable7844TCP (http2)
quic.cftunnel.com1Not applicableNot applicable7844UDP (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.

DomainIPv4IPv6PortProtocolsDescription
api.cloudflare.com104.19.192.29
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		443TCP (HTTPS)Allows cloudflared to query if software updates are available.
update.argotunnel.com104.18.25.129
104.18.24.129		2606:4700::6812:1881
2606:4700::6812:1981		443TCP (HTTPS)Allows cloudflared to query if software updates are available.
github.comGitHub's IP addresses ↗GitHub's IP addresses ↗443TCP (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		443TCP (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		443TCP (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.

    Terminal window
    sudo iptables -L

  2. Allow localhost to communicate with itself.

    Terminal window
    sudo iptables -A INPUT -i lo -j ACCEPT

  3. Allow already established connection and related traffic.

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

  4. Allow new SSH connections.

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

  5. Drop all other ingress traffic.

    Terminal window
    sudo iptables -A INPUT -j DROP

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

    Terminal window
    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.

Terminal window
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
...
Terminal window
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
...
Terminal window
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
...
Terminal window
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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