How to block mail id in do daddy server

To block a mail ID on a DoD (Department of Defense) server, you'll need to use a combination of DNS and email server settings. Here's a step-by-step guide to help you block a mail ID on a DoD server:

Prerequisites:

1. You have administrative access to the DoD server's DNS and email server.
2. You have the necessary permissions to modify DNS records and email server configurations.

Step 1: Update DNS Records

To block a mail ID, you'll need to update the DNS records to prevent the mail ID from receiving emails. You'll need to add a "Sender Policy Framework" (SPF) record and a "DomainKeys Identified Mail" (DKIM) record to the DNS zone file.

SPF Record:

1. Log in to your DNS management console (e.g., DNSimple, Cloudflare, or your DoD server's DNS management tool).
2. Create a new TXT record with the following format:

   v=spf1 a mx -all

   Replace the a and mx with the IP addresses of your email server(s).

DKIM Record:

1. Create a new TXT record with the following format:

   k=rsa; p=<public_key>

   Replace <public_key> with the public key of your email server.

Step 2: Configure Email Server

To block a mail ID, you'll need to configure your email server to reject emails from the blocked mail ID. You can do this by adding a sender filter rule to your email server.

Example:

For Postfix (a popular email server software), you can add the following rule to the /etc/postfix/main.cf file:

sender_relay_maps = hash:/etc/postfix/sender_relay

Create a new file /etc/postfix/sender_relay with the following content:

<blocked_mail_id> REJECT

Replace <blocked_mail_id> with the actual mail ID you want to block.

Step 3: Reload Email Server Configuration

After updating the email server configuration, reload the Postfix service to apply the changes:

sudo service postfix reload

Step 4: Verify Block

To verify that the mail ID is blocked, send an email from the blocked mail ID to a test email address. If the email is rejected, it should be blocked successfully.

Additional Tips:

• Make sure to update the DNS records and email server configuration on all email servers that handle emails for your domain.
• If you're using a cloud-based email service, you may need to contact their support team to block the mail ID.
• Be aware that blocking a mail ID may not be 100% effective, as spammers can use different mail IDs or techniques to bypass the block.

Remember to always follow your organization's security policies and guidelines when blocking mail IDs. If you're unsure about the process or have questions, consult with your IT department or a qualified email administrator.