DNSFilter Knowledge Base

Dynamic DNS

In addition to static IP addresses, DNSFilter allows the use of Dynamic DNS hostnames for your network. This is useful in scenarios where the egress IP - egress IP - An egress IP is the internet-facing, public IP address for a network. There can be multiple IPs for a single network if it is using failover or multiple WAN links. is subject to change, which is common in locations with a residential-grade internet connection (small offices/home offices). We have a list of providers for which we support instantaneous updates, but all dynamic DNS hostnames are automatically updated within 60-90 seconds, regardless of provider.

Networks with Dynamic IPs should use Dynamic Hostnames

It is important that if your external IP address is subject to change, that you implement a Dynamic DNS service and updater software on your network. This is because if the IP address changes, and DNSFilter is not aware of it, you will lose connectivity with our service and external DNS resolution will cease on your network.

If a location does not have Dynamic DNS hostnames configured, and the external IP address changes, users will receive the following notice when they attempt to surf:

I'm already using Dynamic DNS

If you already have a dynamic DNS service, you may simply add the hostname for the desired network as shown below. As your Dynamic DNS updater software provides updates for that hostname, DNSFilter will update our network to expect traffic accordingly. You may want to check if you are using one of our supported providers, and consider switching if your provider is unsupported.

Adding a Dynamic DNS hostname

Adding a Dynamic DNS hostname

I'm not using Dynamic DNS

If you do not have a Dynamic DNS provider, you'll need to create an account with one, and also configure a client that will provide updates on your egress IP - egress IP - An egress IP is the internet-facing, public IP address for a network. There can be multiple IPs for a single network if it is using failover or multiple WAN links. to your provider. Most routers, firewalls, and other network appliances have a Dynamic DNS functionality built in, and you may need to refer to the documentation for the specific network appliance being used in your network.

It's also possible utilize a Dynamic DNS updater on an individual server or computer within a network, in case the network appliance does not have Dynamic DNS built in.

DNSFilter recommends the following Dynamic DNS updater software:

Supported Providers

The following Dynamic DNS providers are directly supported by DNSFilter, and result in instantaneous updates to the DNSFilter system. DNSFilter accomplishes this by proxying requests to these services, thereby updating our own record of your Dynamic DNS hostname, and then forwarding the update to the original provider.

Unsupported Providers

If you're currently using a Dynamic DNS provider which is not in the above list, the Dynamic DNS update may not occur, and it's recommended to use a Supported Provider.

If an Unsupported Provider must be utilized, the device which performs the Dynamic DNS updates cannot utilize DNSFilter for DNS resolution, because DNSFilter will block the request from unknown IP addresses. Some networking equipment and Dynamic DNS updater software (ddclient) allow a third-party DNS server to be used for the DNS lookup portion of the Dynamic DNS update.

If using an Unsupported Provider, and when DNSFilter is not utilized to resolve DNS on that device, DNSFilter will automatically check all dynamic DNS hostnames every 90 seconds for updates, so there will be a slight delay involved.

Mikrotik Routers

Mikrotik routers have the flexibility to use our Dynamic DNS providers above, using the fetch command.

By default, the fetch command uses the "address" and "src-path" properties, but must be changed to use the "url" property as follows:

url="http://members.dyndns.org/nic/updatehostname=$hostname&myip=$currentIP"

However, Mikrotik also runs its own Dynamic DNS service (IP Cloud). To activate this service, type the following commands into the RouterOS terminal:

/ip cloud set ddns-enabled=yes
/ip cloud print

It will print a "dns-name" property which you can input into the DNS Filter dashboard.

Please refer to the following Mikrotik resources for further information:

IP Cloud
Fetch command

FRITZ!Box

Many FRITZ!Box devices use the ISP's DNS servers, and not the DNS servers configured in DHCP/DNS forwarding; there is no way to change this behavior.

If you are using a FRITZ!Box device, you can still use DynDNS using a custom URL by selecting the User-defined option in the Dynamic DNS settings and entering the following URL:

http://dyndns.dnsfilter.com/nic/update?hostname=YourDynDNSHostname&myip=<ipaddr>&username=YourDynDNSUsername&password=YourDynDNSPassword&updater=fritz

Fill out the Domain name, User name, and password fields with your normal DynDNS account credentials.

This will send the request to us, allowing us to update our system, subsequently forwarding the request to DynDNS to update any other services that depend on Dynamic DNS updates.

Contact us for any further information or troubleshooting needs.

DynDNS Passthrough

If your device is unable to use DNSFilter's DNS servers to perform DNS requests, or you require using other DNS servers on this device, you can still use DynDNS if your Dynamic DNS updates device allows for custom Dynamic DNS URLs/domain names

Simply use dyndns.dnsfilter.com, leaving all other information the same, and we will update our system, subsequently forwarding the request to DynDNS to update any other services that depend on Dynamic DNS updates.