• Identifying Senders and Servers:

  • Sender IP Address: When an email is sent, the email server (SMTP server) that processes and sends the email attaches the IP address of the sending device or server to the email header. This IP address identifies the origin of the email.

  • Recipient IP Address: Similarly, the IP address of the recipient's email server may be logged by the sender's email server during the delivery process.

• Tracking and Authentication:

  • Delivery Tracking: Email servers use IP addresses to track the path of an email from sender to recipient. This helps in diagnosing delivery issues, such as bounced emails or delays.

  • Authentication: Techniques like SPF (Sender Policy Framework) and DKIM (DomainKeys Identified Mail) use IP addresses as part of their authentication mechanisms to verify that an email is sent from an authorized server and has not been altered during transmission.

Types of IP Addresses

There are generally two types of IP addresses relevant to emailing:

• IPv4 (Internet Protocol version 4):

  • Example: 192.0.2.1

  • IPv4 addresses are 32-bit numerical labels expressed in four groups of numbers separated by dots. They are the most commonly used type of IP addresses on the Internet.

• IPv6 (Internet Protocol version 6):

  • Example: 2001:0db8:85a3:0000:0000:8a2e:0370:7334

  • IPv6 addresses are 128-bit hexadecimal labels, providing a much larger pool of unique addresses compared to IPv4. They are increasingly being adopted due to the depletion of IPv4 addresses.

Importance of IP Addresses in Emailing

• • Delivery and Routing: IP addresses are essential for routing emails between email servers on the Internet, ensuring that messages are delivered to the correct recipient.

  • Authentication: SPF, DKIM, and DMARC (Domain-based Message Authentication, Reporting, and Conformance) use IP addresses to verify the authenticity of emails, protecting against spoofing and phishing attacks.

  • Tracking and Analytics: Email marketers and administrators use IP addresses to monitor email delivery metrics, such as bounce rates, delivery rates, and spam complaints, to optimize email campaigns and maintain sender reputation.

  • Security: IP addresses can be used to identify and block malicious or spammy senders, helping to maintain the integrity and security of email communications.