Do not send e-mail to me!

Author: Leandro Rodrigues

The Amazon Web Services (AWS) is a cloud computing platform that has datacenters in various locations around the world and provides various web services such as Elastic Compute Cloud (EC2) in which you can use it to instantiate e-mail services. The administrator of email server on EC2 should stick to some important observations about the correct settings for that emails sent by it will widely accepted...

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[vc_row][vc_column][vc_column_text]The Time-based One-Time Password algorithm (TOTP) is an algorithm capable of generating pseudo-random passwords through a shared private key. The algorithm is formalized by RFC 6238 for use in dual factor authentication.   The TOTP is a combination of the private key and the current time of the device that runs the algorithm. Therefore, two devices calculate exactly the same value if they have their...

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[vc_row][vc_column][vc_column_text]Several anti-spam systems provide methods of sending feedback so that e-mail service administrators can learn about complaints against their own senders. These feedbacks are very important for the email service administrator because too many abuses can compromise the reputation of the IP used by the service. If an IP's reputation is compromised, multiple providers may stop receiving messages from that service.   The best-known feedback system is...

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Static IP is allocated to an ISP client under assurance that such IP will never be changed. This warranty is given under a contract between the parties. In contrast, dynamic IP is allocated to the client without any guarantee that it will not be changed by the ISP.   Some people believe that the dynamic IP is one that is constantly changed by the ISP. But this...

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Generic rDNS refers to a sequential name pattern for a large set of IPs in a datacenter or ISP. The generic rDNS is immediately set when the ISP receives the IP block, much before the IP is allocated on a real machine. Therefore, generic rDNS is a name given to IP and not a name given to host.   Examples of generic rDNS   Generic rDNS usually follows a...

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Forward-confirmed reverse DNS (FCrDNS) is an rDNS configuration that defines strong relationship between IP and domain. FCrDNS implementation depends on a joint action between the IP administrator and the domain administrator. When FCrDNS is valid, there is a guarantee that the domain owner has responsibility for the use of IP.   How to check FCrDNS for IPv4   To check the FCrDNS, you must query the rDNS. As an...

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Reverse DNS (rDNS) is the naming method of the machine that is using a given IP and is defined by the IP block administrators through the PTR record in DNS.   How to discover the rDNS of an IPv4   To discover the rDNS of an IPv4, just consult the PTR of the IP reverse form with ".in-addr.arpa". As an example, the IP "209.85.218.43" is transformed into "43.218.85.209.in-addr.arpa" and...

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