Complete Guide to Fetching All DNS Records with `dig`, Automating with Bash Scripts, and Integrating with GitHub Actions Using Resend.com

Advanced

Category: DevOps & Networking

Prerequisites

Familiarity with Bash scripting
Basic understanding of DNS records
Access to GitHub Actions and repository management
Resend.com account setup for API usage

Complete Guide to Fetching All DNS Records with `dig`, Automating with Bash Scripts, and Integrating with GitHub Actions Using Resend.com

Managing DNS configurations for my domain, deanlofts.xyz, requires a quick and efficient way to retrieve all essential DNS records. The default dig command can be cumbersome, and running multiple commands for different record types is time-consuming.

In this guide, I’ll show you how to:

Use dig to fetch all useful DNS records in one go.
Create a Bash script that processes the output and saves it in .txt and .csv formats.
Utilize the output creatively for various DevOps use cases.
Integrate the process with GitHub Actions for continuous monitoring and notification.
Use Resend.com for sending email notifications and reports.

Fetching All DNS Records at Once
Organizing and Saving the Output
Processing Output with Bash Scripts
Creative Uses of the Output
DevOps Use Cases with GitHub Actions
- 5.1 Automating DNS Monitoring
- 5.2 Integrating with CI/CD Pipelines
- 5.3 Generating DNS Reports
Conclusion

1. Fetching All DNS Records at Once

The Challenge

By default, dig retrieves one DNS record type at a time. Running multiple commands is inefficient.

The Solution

Use a Bash loop to query multiple DNS record types in one command.

for type in A AAAA MX NS CNAME TXT SOA; do
  dig deanlofts.xyz "$type" +noall +answer
done

Sample Output:

deanlofts.xyz.    300 IN A     104.21.35.16
deanlofts.xyz.    300 IN A     172.67.167.178
deanlofts.xyz.    300 IN AAAA  2606:4700:3036::6815:2310
deanlofts.xyz.    300 IN AAAA  2606:4700:3035::ac43:a7b2
deanlofts.xyz.    0   IN MX    1 aspmx.l.google.com.
...

2. Organizing and Saving the Output

Adding Headers

To make the output more readable, add headers for each record type.

for type in A AAAA MX NS CNAME TXT SOA; do
  echo "===== $type Records ====="
  dig deanlofts.xyz "$type" +noall +answer
done

Saving to a Text File

You can redirect the output to a .txt file.

for type in A AAAA MX NS CNAME TXT SOA; do
  echo "===== $type Records =====" >> dns_records.txt
  dig deanlofts.xyz "$type" +noall +answer >> dns_records.txt
done

Check the File:

cat dns_records.txt

3. Processing Output with Bash Scripts

Creating a Bash Script

Step 1: Create `get_dns_records.sh`

nano get_dns_records.sh

Step 2: Add the Following Script

#!/bin/bash

DOMAIN="deanlofts.xyz"
OUTPUT_FILE="dns_records.txt"

# Record types to query
RECORD_TYPES=(A AAAA MX NS CNAME TXT SOA)

# Remove output file if it exists
rm -f "$OUTPUT_FILE"

for type in "${RECORD_TYPES[@]}"; do
  echo "===== $type Records =====" >> "$OUTPUT_FILE"
  dig "$DOMAIN" "$type" +noall +answer >> "$OUTPUT_FILE"
done

Step 3: Make the Script Executable

chmod +x get_dns_records.sh

Step 4: Run the Script

./get_dns_records.sh

4. Creative Uses of the Output

Exporting to CSV Format

Step 1: Create `dns_to_csv.sh`

nano dns_to_csv.sh

Step 2: Add the Script Content

#!/bin/bash

DOMAIN="deanlofts.xyz"
OUTPUT_FILE="dns_records.csv"

# Initialize CSV file with headers
echo "Record Type,Name,TTL,Class,Type,Data" > "$OUTPUT_FILE"

RECORD_TYPES=(A AAAA MX NS CNAME TXT SOA)

for type in "${RECORD_TYPES[@]}"; do
  dig "$DOMAIN" "$type" +noall +answer |
  awk -v rt="$type" '{print rt "," $1 "," $2 "," $3 "," $4 "," substr($0, index($0,$5))}' >> "$OUTPUT_FILE"
done

Step 3: Make the Script Executable

chmod +x dns_to_csv.sh

Step 4: Run the Script

./dns_to_csv.sh

Step 5: View the CSV File

cat dns_records.csv

Sample CSV Output:

Record Type,Name,TTL,Class,Type,Data
A,deanlofts.xyz.,300,IN,A,104.21.35.16
A,deanlofts.xyz.,300,IN,A,172.67.167.178
AAAA,deanlofts.xyz.,300,IN,AAAA,2606:4700:3036::6815:2310
...

Parsing Specific Data

Extract just the IP addresses from A records.

dig deanlofts.xyz A +short > ip_addresses.txt

5. DevOps Use Cases with GitHub Actions

5.1 Automating DNS Monitoring

Monitor DNS records for changes and alert when discrepancies occur.

Step 1: Create a Repository

Create a new GitHub repository to store your scripts.

Step 2: Add Your Scripts

Upload get_dns_records.sh and dns_to_csv.sh to the repository.

Step 3: Create a GitHub Actions Workflow

Create a file .github/workflows/dns-monitor.yml in your repository.

name: DNS Monitor

on:
  schedule:
    - cron: "0 0 * * *" # Runs daily at midnight
  workflow_dispatch:

jobs:
  check-dns:
    runs-on: ubuntu-latest
    steps:
      - name: Checkout Repository
        uses: actions/checkout@v4

      - name: Run DNS Records Script
        run: |
          chmod +x get_dns_records.sh
          ./get_dns_records.sh

      - name: Compare with Previous Records
        run: |
          if [ -f dns_records_previous.txt ]; then
            DIFF=$(diff dns_records_previous.txt dns_records.txt || true)
            if [ "$DIFF" != "" ]; then
              echo "DNS records have changed."
              echo "$DIFF" > dns_diff.txt
            else
              echo "No changes in DNS records."
            fi
          else
            echo "No previous DNS records found."
          fi
          cp dns_records.txt dns_records_previous.txt

      - name: Upload Diff Artifact
        if: exists('dns_diff.txt')
        uses: actions/upload-artifact@v4
        with:
          name: dns_diff
          path: dns_diff.txt

      - name: Send Notification via Resend.com
        if: exists('dns_diff.txt')
        run: |
          curl -X POST https://api.resend.com/emails \
          -H "Authorization: Bearer ${{ secrets.RESEND_API_KEY }}" \
          -H "Content-Type: application/json" \
          -d '{
            "from": "DNS Monitor <monitor@deanlofts.xyz>",
            "to": ["youremail@example.com"],
            "subject": "DNS Records Changed for deanlofts.xyz",
            "text": "The DNS records for deanlofts.xyz have changed. See the attached diff for details.",
            "attachments": [
              {
                "filename": "dns_diff.txt",
                "content": "'"$(base64 dns_diff.txt)"'",


                "content_type": "text/plain"
              }
            ]
          }'

Step 4: Set Up Resend.com

Create a Resend.com account: Resend.com Signup.
Obtain an API Key: Navigate to the API keys section and create a new API key.
Add Secret to GitHub:
- RESEND_API_KEY: Your Resend.com API key.

Step 5: Configure DNS for Email Sending

Verify Your Domain: Resend.com will provide DNS records to verify your domain ownership and enable email sending.
Add the Required DNS Records: Use your DNS provider to add the TXT and MX records provided by Resend.com.

Step 6: Commit and Push

git add .
git commit -m "Add DNS monitoring workflow with Resend.com notifications"
git push origin main

Why Use Resend.com?

API-Based Email Sending: Resend.com provides a straightforward API for sending emails, which works well with GitHub Actions.
No SMTP Restrictions: Since you’re using an API, you avoid the SMTP issues that can occur with Gmail or other SMTP servers.
Attachment Support: Resend.com allows you to send attachments, which is useful for including the dns_diff.txt file.

5.2 Integrating with CI/CD Pipelines

Ensure DNS records are correct before deploying applications.

Step 1: Modify Your Deployment Workflow

Add a step in your existing GitHub Actions deployment workflow to validate DNS records.

- name: Validate DNS Records
  run: |
    chmod +x get_dns_records.sh
    ./get_dns_records.sh
    # Add validation logic here
    # For example, check if the A record matches the expected IP
    EXPECTED_IP="104.21.35.16"
    ACTUAL_IP=$(dig deanlofts.xyz A +short | head -n1)
    if [ "$ACTUAL_IP" != "$EXPECTED_IP" ]; then
      echo "DNS A record does not match the expected IP."
      exit 1
    fi

Step 2: Proceed with Deployment

If the validation passes, the workflow continues to deploy your application.

5.3 Generating DNS Reports

Provide stakeholders with regular reports on DNS configurations.

Step 1: Schedule Report Generation

Modify your GitHub Actions workflow to generate reports weekly.

on:
  schedule:
    - cron: "0 0 * * 0" # Runs weekly on Sundays at midnight

Step 2: Add Report Generation Step

- name: Generate DNS CSV Report
  run: |
    chmod +x dns_to_csv.sh
    ./dns_to_csv.sh

- name: Upload DNS Report
  uses: actions/upload-artifact@v4
  with:
    name: dns_report
    path: dns_records.csv

Step 3: Send Reports via Email Using Resend.com

Integrate an action to send the report via Resend.com.

- name: Send Weekly DNS Report via Resend.com
  run: |
    curl -X POST https://api.resend.com/emails \
    -H "Authorization: Bearer ${{ secrets.RESEND_API_KEY }}" \
    -H "Content-Type: application/json" \
    -d '{
      "from": "DNS Report <report@deanlofts.xyz>",
      "to": ["youremail@example.com"],
      "subject": "Weekly DNS Report for deanlofts.xyz",
      "text": "Please find the attached DNS report for deanlofts.xyz.",
      "attachments": [
        {
          "filename": "dns_records.csv",
          "content": "'"$(base64 dns_records.csv)"'",
          "content_type": "text/csv"
        }
      ]
    }'

Note: Ensure that you have set up your Resend.com account and verified your domain to send emails from @deanlofts.xyz.

6. Conclusion

By customizing the dig command and leveraging Bash scripting, we’ve:

Created a personalized and efficient way to fetch all DNS records.
Developed scripts to process and save output in .txt and .csv formats.
Explored creative and practical applications for DevOps workflows.
Integrated the entire process with GitHub Actions for automated monitoring and reporting.
Used Resend.com to send email notifications and reports, avoiding SMTP restrictions.

These tools not only streamline daily tasks but also enhance monitoring and reporting capabilities for DNS configurations, all within your preferred CI/CD environment.

Additional Notes:

Resend.com Benefits: By using Resend.com, you can send emails reliably from GitHub Actions without worrying about SMTP server restrictions or IP blocks.
API Usage: The Resend.com API allows you to send emails with attachments, which is ideal for including diffs or reports.
Domain Verification: Make sure to complete domain verification steps provided by Resend.com to send emails from your domain.

Alternative Notification Methods:

If you prefer not to use email notifications, you can integrate other services like Slack, Microsoft Teams, or even SMS notifications using appropriate APIs and GitHub Actions.

Using Slack Notifications:

- name: Send Slack Notification
  if: exists('dns_diff.txt')
  uses: slackapi/slack-github-action@v1.27.0
  with:
    payload: |
      {
        "channel": "#your-channel",
        "text": "DNS records have changed for deanlofts.xyz. See the attached diff.",
        "attachments": [
          {
            "text": "$(cat dns_diff.txt)"
          }
        ]
      }
  env:
    SLACK_BOT_TOKEN: ${{ secrets.SLACK_BOT_TOKEN }}

Note: You’ll need to create a Slack app and obtain a bot token. Add SLACK_BOT_TOKEN to your GitHub repository secrets.

Complete Guide to Fetching All DNS Records with `dig`, Automating with Bash Scripts, and Integrating with GitHub Actions Using Resend.com

Prerequisites

Complete Guide to Fetching All DNS Records with dig, Automating with Bash Scripts, and Integrating with GitHub Actions Using Resend.com

Table of Contents

1. Fetching All DNS Records at Once

The Challenge

The Solution

2. Organizing and Saving the Output

Adding Headers

Saving to a Text File

3. Processing Output with Bash Scripts

Creating a Bash Script

Step 1: Create get_dns_records.sh

Step 2: Add the Following Script

Step 3: Make the Script Executable

Step 4: Run the Script

4. Creative Uses of the Output

Exporting to CSV Format

Step 1: Create dns_to_csv.sh

Step 2: Add the Script Content

Step 3: Make the Script Executable

Step 4: Run the Script

Step 5: View the CSV File

Parsing Specific Data

5. DevOps Use Cases with GitHub Actions

5.1 Automating DNS Monitoring

Step 1: Create a Repository

Step 2: Add Your Scripts

Step 3: Create a GitHub Actions Workflow

Step 4: Set Up Resend.com

Step 5: Configure DNS for Email Sending

Step 6: Commit and Push

Why Use Resend.com?

5.2 Integrating with CI/CD Pipelines

Step 1: Modify Your Deployment Workflow

Step 2: Proceed with Deployment

5.3 Generating DNS Reports

Step 1: Schedule Report Generation

Step 2: Add Report Generation Step

Step 3: Send Reports via Email Using Resend.com

6. Conclusion

Complete Guide to Fetching All DNS Records with `dig`, Automating with Bash Scripts, and Integrating with GitHub Actions Using Resend.com

Step 1: Create `get_dns_records.sh`

Step 1: Create `dns_to_csv.sh`