Dynadot

Dynadot Dynamic DNS (DDNS) Setup

This page documents how to configure Dynamic DNS for Dynadot and automatically update the A record when the public IP address changes.

Requirements

• Dynadot account
• Domain using Dynadot DNS
• DDNS password generated in Dynadot
• Ubuntu server with outbound HTTPS access

Dynadot configuration

1. Enable Dynadot DNS

1. Log in to Dynadot
2. Go to My Domains
3. Click the domain
4. Set DNS → Dynadot DNS

2. Enable Dynamic DNS

1. Domain settings → Dynamic DNS
2. Enable DDNS
3. Generate a DDNS password
4. Save it securely

3. Required values

Field	Example
Domain	example.com
Subdomain	@ or www
Record type	A (IPv4) or AAAA (IPv6)
DDNS password	(generated in Dynadot)

Dynadot update endpoint

Dynadot accepts HTTP GET updates:

https://www.dynadot.com/set_ddns

Parameters:

• domain
• subDomain
• type
• ip
• pwd
• ttl (optional)

Ubuntu auto-update script

Script: dynadot-ddns.sh

nano .env

Add this:

# SUBDOMAIN should be left empty if root domain.
DOMAIN=<domain>
SUBDOMAIN=
TYPE=A
PASSWORD=YOUR_DYNADOT_PASSWORD
TTL=300

chmod 600 .env

#!/bin/bash

# ===== CONFIG =====
SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
ENV_DDNS="$SCRIPT_DIR/.env"                # Dynadot settings
ENV_DISCORD="$SCRIPT_DIR/../bots/discord/.env"  # Discord bot settings
IP_FILE="$SCRIPT_DIR/dynadot_last_ip.txt"
LOG_FILE="$SCRIPT_DIR/log.txt"
LOG_ROTATED="$SCRIPT_DIR/log.txt.1"

# ===== LOG ROTATION =====
if [ -f "$LOG_FILE" ]; then
    mv -f "$LOG_FILE" "$LOG_ROTATED"
fi

# ===== LOAD ENV =====
# Dynadot settings
if [ -f "$ENV_DDNS" ]; then
    export $(grep -v '^#' "$ENV_DDNS" | xargs)
else
    echo "ERROR: Dynadot .env not found at $ENV_DDNS"
    exit 1
fi

# Discord bot settings
if [ -f "$ENV_DISCORD" ]; then
    export $(grep -v '^#' "$ENV_DISCORD" | xargs)
else
    echo "ERROR: Discord .env not found at $ENV_DISCORD"
    exit 1
fi

# ===== CHECK REQUIRED ENV VARIABLES =====
for var in DOMAIN PASSWORD TTL DISCORD_BOT_TOKEN LOGS_CHANNEL_ID; do
    if [ -z "${!var}" ]; then
        echo "ERROR: $var not set in .env files"
        exit 1
    fi
done

CHANNEL_ID="$LOGS_CHANNEL_ID"

# ===== LOG FUNCTION =====
log() {
    echo "$(date '+%Y-%m-%d %H:%M:%S') - $1" >> "$LOG_FILE"
}

# ===== DISCORD FUNCTION =====
send_discord() {
    local result="$1"
    local ip_old="$2"
    local ip_new="$3"
    local timestamp
    timestamp=$(date -u +"%Y-%m-%dT%H:%M:%SZ")  # ISO 8601 UTC

    local json_payload=$(cat <<EOF
{
  "content": "The domain name #${DOMAIN} dynamically resolves to ${result}.",
  "embeds": [
    {
      "description": "Domains: ${DOMAIN}\nResult: ${result}\nOld IP: ${ip_old}\nNew IP: ${ip_new}\nTime: ${timestamp} UTC",
      "color": 15258703,
      "author": { "name": "DDNS" },
      "footer": { "text": "DDNS ${result}" }
    }
  ]
}
EOF
)

    curl -s -H "Authorization: Bot $DISCORD_BOT_TOKEN" \
         -H "Content-Type: application/json" \
         -X POST \
         -d "$json_payload" \
         "https://discord.com/api/v9/channels/${CHANNEL_ID}/messages" > /dev/null
}

log "---- Script started ----"

# ===== GET CURRENT IP =====
CURRENT_IP=$(curl -s https://checkip.amazonaws.com)
if [ -z "$CURRENT_IP" ]; then
    log "ERROR: Could not fetch public IP"
    send_discord "ERROR" "N/A" "N/A"
    exit 1
fi
CURRENT_IP=$(echo "$CURRENT_IP" | tr -d '[:space:]')
log "Current IP: $CURRENT_IP"

# ===== READ LAST IP =====
if [ -f "$IP_FILE" ]; then
    LAST_IP=$(cat "$IP_FILE")
else
    LAST_IP=""
    touch "$IP_FILE"
    log "Created IP file"
fi
log "Last IP: $LAST_IP"

# ===== COMPARE =====
if [ "$CURRENT_IP" = "$LAST_IP" ]; then
    log "IP unchanged. No update needed."
    exit 0  # No Discord notification if unchanged
fi

# ===== UPDATE DYNDOT =====
SUBDOMAIN=${SUBDOMAIN:-""}  # default to empty if not set
TYPE=${TYPE:-"A"}           # default to A record
UPDATE_URL="https://www.dynadot.com/set_ddns?containRoot=true&domain=${DOMAIN}&subDomain=${SUBDOMAIN}&type=${TYPE}&ip=${CURRENT_IP}&pwd=${PASSWORD}&ttl=${TTL}"
RESPONSE=$(curl -s "$UPDATE_URL")
log "Dynadot response: $RESPONSE"

# ===== SAVE IP & DISCORD =====
if echo "$RESPONSE" | grep -qi "success"; then
    echo "$CURRENT_IP" > "$IP_FILE"
    log "IP updated and saved."
    send_discord "SUCCESS" "$LAST_IP" "$CURRENT_IP"
else
    log "ERROR: Dynadot update failed."
    send_discord "FAIL" "$LAST_IP" "$CURRENT_IP"
fi

log "---- Script finished ----"
echo

Installation

1. Save script

sudo nano /usr/local/bin/dynadot-ddns.sh

Paste script and edit variables.

2. Make executable

sudo chmod +x /usr/local/bin/dynadot-ddns.sh

3. Test manually

/usr/local/bin/dynadot-ddns.sh

4. Add cron job (every 5 minutes)

crontab -e

Add:

*/5 * * * * /usr/local/bin/dynadot-ddns.sh

Security notes

• Store DDNS password securely
• Limit file permissions
• Do not commit the script to public repositories

References

• Dynadot Help – Dynamic DNS
• Dynadot API documentation