pfSense

https://www.nic.ru/help/dynamic-dns-for-developers_5810.html:
Request for IP address update looks like this:

GET https://api.nic.ru/dyndns/update?hostname=myhost1.test.ru,myhost2.test.ru&myip=192.168.1.1

Authorization: Basic <base64-encoded-string>

Alternative option:

GET https://username:password@api.nic.ru/dyndns/update?hostname=myhost1.test.ru,myhost2.test.ru&myip=192.168.1.1&ipv6=::1

Parameters transferred in the query:

hostname - receives a list of hostnames for which IP addresses are to be assigned, separated with commas;
myip – new IPv4 address;
ipv6 – new IPv6 address.

Parameters myip and ipv6 are optional. If a request has no myip, then will be set IPv4 address from which connection was made. If a request has no ipv6, then IPv6 address will not be set.

In case of success, HTTP code 200 will be returned; response body will look like this:

good 192.168.1.1

good ::1

If IP address for domain myhost2.test.ru is not updated because record is absent, then response body will look like this:

good 192.168.1.33

nohost

In case of authentication error, HTTP code 200 will be returned; response body will look like this:

badauth

The response may also include character codes notfqdn and dnserr.