How e-mail works

When you send an e-mail, it does not go directly to the recipient’s computer. The e-mail first goes to your Internet Service Provider (ISP)’s mail server. From that mail server, your e-mail is routed to a destination mail server which stores that e-mail until the person for whom the e-mail is intended checks his or her e-mail. In the process of checking for e-mail, that person will retrieve or download that e-mail from the mail server where it is being stored to their PC.

Why SMTP Authentication?

SMTP is an internet protocol (or a set of rules) that are followed in order to transfer e-mail from one mail server to another mail server. Generally, this service is anonymous— meaning that there is no way to verify the sender of an e-mail. In order to make their e-mail service more secure, most ISPs need to verify that e-mail is being sent by genuine customers rather than unauthorized persons (as happens when spam or junk mail is sent). SMTP AUTH allows an ISP to do this by checking and verifying a customer’s user name and password when they try to send e-mail. Without SMTP authentication the server would be an “open relay” that could be used by unauthorized people to send spam and viruses.

Why SSL?

SSL is a set of rules that were developed to securely transfer information over the Internet. SSL enables secure communication over the Internet so as to prevent unauthorized access to information being transmitted.

What Is Reverse DNS?

Computers on the Internet identify each other using either a set of numbers called an IP (Internet Protocol) address. Each IP address assigned to a computer on the Internet is unique to a particular computer. In other words, no two computers may have the same IP address. Since mail servers are computers too, they also are identified on the Internet by a unique IP address.   A computer may also be identified by a unique name called a hostname. A hostname is really just a combination of words that identifies the particular computer and the network it is on. For example, our GuyanaNet mail server is called mail and it is on the guyana.net.gy network, so its hostname is mail.guyana.net.gy.  

DNS, or the Domain Name System, is a system by which a check is made to determine what hostname is associated with a given IP address. In Reverse DNS, the opposite happens: a check is made to determine what IP address is associated with a given hostname.  

Reverse DNS checks can play an important role in filtering spam (or junk e-mail). Spammers (those who send junk e-mail) typically uses an invalid IP address, i.e., an IP address that does not match the hostname.   Our GuyanaNet mail server now performs a reverse DNS check on the originating mail server of incoming e-mail. If a reverse DNS check finds an e-mail coming from an invalid IP address, the GuyanaNet mail server will reject that e-mail. In other words, if someone you know has an e-mail address associated with a mail server that does not have reverse DNS set up correctly, you will not be able to receive e-mail sent by that person to your GuyanaNet e-mail address.

Federal Law prohibits email senders from disguising their point of origin (by not having a correctly set up reverse DNS). RFC 1912 Section 2.1 requires working reverse DNS to determine a true point of origin.   If you are not receiving e-mail from someone because of this problem, please report this to us by either calling our technical support hotline on 227-6045 or by e-mailing us at support@guyana.net.gy . We will do our best to have the administrator of the mail server in question comply with this reverse DNS requirement.

Guyana Net Inc. Postmaster