← Porkbun Dynamic DNS Script


This tutorial is about a very simple bash script that I have made to update my DNS records on my registrar. This script works, in particular, with Porkbun, the registrar that I use for my domains.

The Script

#!/bin/sh

# This script will grab your ip from an IP api and push it to the porkbun API
# It was recommended to set the cronjob to whatever your TTL is.
#
# Example cronjob for a 600 seconds TTL:
# */10 * * * * porkbun-ddns

domain=""             # The domain name
subdomain=""          # The subdomain, yes you can leave it blank, see below CNAMEs
secretapikey=""       # Your secret API key
apikey=""             # The API key, no idea why they split it in two
ipapi="ip.me"         # A particular website that will return your IP(v4) as plain text if you curl it
cachefile="/root/.ddns-cache" # A file, where your IP will be cached

ip=$(curl -s4 $ipapi) # Gets your ip

if [ -z "$ip" ]; then # If there was an error, exit
    echo "Error getting IP."
    exit 1
fi

if [ -f "$cachefile" ]; then # If the cache file exists read it
    read -r cachedip < "$cachefile"
fi

# Only exec if the IP != to the ip in the cache file or if the file doesn't exist
if [ "$ip" != "$cachedip" ] || [ -z "$cachedip" ]; then
    echo "$ip" > "$cachefile" # Cache the IP

    # Push the new IP to Porkbun, docs see below
    curl -X POST -H "Content-Type: application/json" -d "{
        \"secretapikey\": \"$secretapikey\",
        \"apikey\": \"$apikey\",
        \"content\": \"$ip\",
        \"ttl\": \"600\"
    }" https://api.porkbun.com/api/json/v3/dns/editByNameType/"$domain"/A/"$subdomain"
    echo
else
    echo "Your IP has not changed."
fi

Setting it up

After downloading the script with wget or something and editing it, make it executable with chmod +x porkbun-ddns, then copy it somewhere in your $PATH. I think /usr/local/bin/ is the standard for scripts and random binaries like this.

Now you need to make a cronjob. As stated on the script, it was recommended that the cronjob’s cycle to be set to whatever your domain’s TTL is, in my case 600 seconds or 10 minutes:

crontab -e

*/10 * * * * /usr/local/bin/porkbun-ddns

chmod and Change Owner

Maybe changing the mode of the script would be a good idea because it contains the credentials for Porkbun:

chmod 770 /usr/local/bin/porkbun-ddns
chown root:root /usr/local/bin/porkbun-ddns

# Now check
ls -laFh /usr/local/bin/porkbun-ddns

The output should be something like:

.rwxrwx--- root root 1.0 KB Sat Jan 27 23:35:29 2024 porkbun-ddns*

Happy self-hosting!

© 2022-2024 - konakona.moe - all rights reserved Last Mod.: 2024-10-16 | Created On: 2024-01-31 | History