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E-mail Verification Considerations
E-mail Verification, by its very nature is quite complex and a somewhat inaccurate procedure. There are many factors that influence e-mail verification. E-mail addresses belonging to major domains like hotmail.com or rediff.com, can almost always be verified with 100% accuracy. However, verification of e-mails belonging to domains owned by organizations, institutes, universities etc., may be inaccurate. Smart Email Verifier provides many features that can improve your success rate of e-mail verification to a great extent.
E-mail Verification Procedure
Put in simple words, e-mail addresses are verified by
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Checking the syntax: That is, Smart Email Verifier makes sure that the address is put together correctly. Something like "joe, smith@home" would be marked invalid here because that is not a possible e-mail address.
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Checking the domain: The part of an e-mail address after the "@" sign is the domain. For bill@mydomain.com, "mydomain.com" is the domain. Smart Email Verifier connects to a Domain Name Service server (DNS Server) and checks whether the domain in the e-mail address really exists.
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Checking for a mailbox: Smart Email Verifier analyzes the address, connects to the mail server that should be accepting e-mail for it, and requests validation that a mail account exists for the address in the list.
Factors that Influence E-mail Verification
Here are few factors that influence e-mail verification and how Smart Email Verifier can help you to minimize or overcome them:
Network Traffic
Network traffic will cause either the DNS server and/or the SMTP server to respond slowly or not respond at all. The connection, therefore, will eventually time out. Addresses will thus remain unchecked. Smart Email Verifier provides a multi-threaded and a multi-verification engine that is capable of verifying multiple addresses at the same time within the same connection. If the e-mail remains unchecked then Smart Email Verifier can try again a configurable number of times before finally reporting the result. This helps reducing the number of unchecked e-mails, thus improving accuracy.
Reverse Verification
Reverse Verification is a technique employed by SMTP servers, particularly those that belong to institutes, organizations, universities etc., to minimize spam and ensure security. When an SMTP server employing such a technique is queried about an e-mail, it first reverse verifies the querying e-mail (Mail From) to ensure that it exists and then lets the verification procedure to proceed. To overcome Reverse Verification, always use a valid IP address and e-mail address in HELO and "Mail From" fields respectively. To configure HELO and “Mail From” in Smart Email Verifier select Options from the Tools menu and click the SMTP tab.
False Positive
This is a technique that many administrators use to increase security and anonymity. This technique also helps to reduce the number of hits on their SMTP servers eventually with time, so that their servers are not unnecessarily overburdened. When an SMTP server that employs such a technique is queried for an e-mail, it always responds with a valid result. There is no way of knowing if an e-mail address belonging to such a domain exists or not. If you know that an SMTP server uses this technique then it is best to add a rule in Smart Email Verifier that will mark all e-mails belonging to this domain as valid. To use rules, select Options from the Tools menu and then select the Rules tab. As rules are applied even before e-mail verification starts, adding such a rule will increase verification speed.
False Negative
Similar to False Positive, this is a rare technique used by administrator for the same purpose. When an SMTP server that employs such a technique is queried for an e-mail, it always responds with an invalid result. As with False Positive, there is no way of knowing if an e-mail address belonging to such a domain exists or not. If you know that an SMTP server uses this technique then it is best to add a rule in Smart Email Verifier that will mark all e-mails belonging to this domain as invalid. To use rules, select Options from the Tools menu and then select the Rules tab.
Spam Blocking and Blacklisting
E-mail spam is on the increase and so are techniques to stop it. Many organizations record IP addresses or e-mail addresses that are known to originate spam so that they can be blocked. This is known as "Spam Blacklisting" and is the lists are regularly updated. If your IP is on the list then many SMTP servers may not even accept the connection originating from your IP.
Endnote
False Positive, False Negative, Spam Blocking, and Blacklisting are inherently impossible to completely avoid, and make e-mail verification an inaccurate procedure. There are many other related factors that may further influence e-mail verification. There will always be a small percentage of e-mail addresses that will time out or their validity will not be accurately established.
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