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#+date: [2022-03-23 Wed 00:00:00]
#+title: Dynamic DNS Updates via the Cloudflare API
#+description: Automatically updating DNS A and AAAA records via the Cloudflare API.
#+slug: cloudflare-dns-api
#+filetags: :security:
* DDNS: Dynamic DNS
:PROPERTIES:
:CUSTOM_ID: ddns-dynamic-dns
:END:
If you're hosting a service from a location with DDNS (Dynamic Domain Name
System), where your internet protocol (IP)address may change at any time, you
must have a solution to update the DNS (Domain Name System) so that you can
access your service even when the IP of the server changes.
The process below uses the [[https://api.cloudflare.com/][Cloudflare API]] (application programming interface) to
update DNS =A= and =AAAA= records with the server's current IP. If you use
another DNS provider, you will have to find a way to update your DNS (or find a
way to get a static IP).
First, install =jq= since we will use it in the next script:
#+begin_src sh
sudo apt install jq
#+end_src
Next, create a location for your DDNS update scripts and open the first script:
#+begin_src sh
mkdir ~/ddns
nano ~/ddns/update.sh
#+end_src
The following =update.sh= script will take all of your domains and subdomains
and check Cloudflare to see if the current =A= and =AAAA= records match your
server's IP address. If not, it will update the records.
#+begin_src sh
# file: update.sh
#!/bin/bash
# Update TLDs
domains=(example.com example.net)
for domain in "${domains[@]}"
do
echo -e "\nUpdating $domain..."
zone_name=$domain /home/<your-username>/ddns/ddns.sh
done
# Update subdomains for example.com
domain=example.com
subdomains=(photos.example.com)
for subdomain in "${subdomains[@]}"
do
echo -e "\nUpdating $subdomain..."
zone_name=$domain dns_record=$subdomain /home/<your-username>/ddns/ddns.sh
done
#+end_src
Next, open up the =ddns.sh= script. Paste the following into the script and
update the =api_token= and =email= variables.
#+begin_src sh
nano ~/ddns/ddns.sh
#+end_src
*Note*: If you want your DNS records to be proxied through Cloudflare, find and
update the following snippet: ="proxied":false}"= to say =true= instead of
=false=.
#+begin_src sh
# file: ddns.sh
#!/bin/bash
# based on https://gist.github.com/Tras2/cba88201b17d765ec065ccbedfb16d9a
# initial data; they need to be filled by the user
## API token
api_token=<YOUR_API_TOKEN>
## email address associated with the Cloudflare account
email=<YOUR_EMAIL>
# get the basic data
ipv4=$(curl -s -X GET -4 https://ifconfig.co)
ipv6=$(curl -s -X GET -6 https://ifconfig.co)
user_id=$(curl -s -X GET "https://api.cloudflare.com/client/v4/user/tokens/verify" \
-H "Authorization: Bearer $api_token" \
-H "Content-Type:application/json" \
| jq -r '{"result"}[] | .id'
)
echo "Your IPv4 is: $ipv4"
echo "Your IPv6 is: $ipv6"
# check if the user API is valid and the email is correct
if [ $user_id ]
then
zone_id=$(curl -s -X GET "https://api.cloudflare.com/client/v4/zones?name=$zone_name&status=active" \
-H "Content-Type: application/json" \
-H "X-Auth-Email: $email" \
-H "Authorization: Bearer $api_token" \
| jq -r '{"result"}[] | .[0] | .id'
)
# check if the zone ID is
if [ $zone_id ]
then
# check if there is any IP version 4
if [ $ipv4 ]
then
dns_record_a_id=$(curl -s -X GET "https://api.cloudflare.com/client/v4/zones/$zone_id/dns_records?type=A&name=$dns_record" \
-H "Content-Type: application/json" \
-H "X-Auth-Email: $email" \
-H "Authorization: Bearer $api_token"
)
# if the IPv6 exist
dns_record_a_ip=$(echo $dns_record_a_id | jq -r '{"result"}[] | .[0] | .content')
echo "The set IPv4 on Cloudflare (A Record) is: $dns_record_a_ip"
if [ $dns_record_a_ip != $ipv4 ]
then
# change the A record
curl -s -X PUT "https://api.cloudflare.com/client/v4/zones/$zone_id/dns_records/$(echo $dns_record_a_id | jq -r '{"result"}[] | .[0] | .id')" \
-H "Content-Type: application/json" \
-H "X-Auth-Email: $email" \
-H "Authorization: Bearer $api_token" \
--data "{"type":"A","name":"$dns_record","content":"$ipv4","ttl":1,"proxied":false}" \
| jq -r '.errors'
else
echo "The current IPv4 and DNS record IPv4 are the same."
fi
else
echo "Could not get your IPv4. Check if you have it; e.g. on https://ifconfig.co"
fi
# check if there is any IP version 6
if [ $ipv6 ]
then
dns_record_aaaa_id=$(curl -s -X GET "https://api.cloudflare.com/client/v4/zones/$zone_id/dns_records?type=AAAA&name=$dns_record" \
-H "Content-Type: application/json" \
-H "X-Auth-Email: $email" \
-H "Authorization: Bearer $api_token"
)
# if the IPv6 exist
dns_record_aaaa_ip=$(echo $dns_record_aaaa_id | jq -r '{"result"}[] | .[0] | .content')
echo "The set IPv6 on Cloudflare (AAAA Record) is: $dns_record_aaaa_ip"
if [ $dns_record_aaaa_ip != $ipv6 ]
then
# change the AAAA record
curl -s -X PUT "https://api.cloudflare.com/client/v4/zones/$zone_id/dns_records/$(echo $dns_record_aaaa_id | jq -r '{"result"}[] | .[0] | .id')" \
-H "Content-Type: application/json" \
-H "X-Auth-Email: $email" \
-H "Authorization: Bearer $api_token" \
--data "{"type":"AAAA","name":"$dns_record","content":"$ipv6","ttl":1,"proxied":false}" \
| jq -r '.errors'
else
echo "The current IPv6 and DNS record IPv6 are the same."
fi
else
echo "Could not get your IPv6. Check if you have it; e.g. on https://ifconfig.co"
fi
else
echo "There is a problem with getting the Zone ID. Check if the Zone Name is correct."
fi
else
echo "There is a problem with either the email or the password"
fi
#+end_src
Once the script is saved and closed, make the scripts executable:
#+begin_src sh
chmod +x ~/ddns/ddns.sh
chmod +x ~/ddns/update.sh
#+end_src
You can test the script by running it manually:
#+begin_src sh
./update.sh
#+end_src
To make sure the scripts run automatically, add it to the =cron= file so that it
will run on a schedule. To do this, open the cron file:
#+begin_src sh
crontab -e
#+end_src
In the =cron= file, paste the following at the bottom of the editor:
#+begin_src sh
,*/5 ** ** ** ** bash /home/<your_username>/ddns/update.sh
#+end_src
|
