Common Issues Encountered Verifying Email Addresses

Common Issues Encountered Verifying Email Addresses


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Description - Email verification and spamtrap removal platform. One of the few platforms that can truly remove honeypots and spamtraps from email lists.



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Published 08 March 2018
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Common Issues Encountered VerifyingEmail Addresses
VerifyingEmail Addresses is a complicated business.
You would not be here if that was not the case. Hard bounces are a set metric for ESP’s and delivery. Too many hard bounces and your delivery tanks. Over five to ten percent and most ESP’s will kickyou off theplatform. Manydomains these days use them as a wayto block senders and gauge whether the mail is good or not. uses multiple methods to verifythe email addresses forhard bounce removal. We use static tables, MX lookups, and a final SMTP connection toprovide the most accurate reportingpossible.
Many of the large service providers like Gmail, Hotmail, and AOL provide bounce replies in realtime duringthe SMTP session. Some emailproviders do notgive realtime bounce replies but will send the bounce messages via email. Some providers will accept all messages to all recipients whether theyare valid or not and do notprovide replies. This makes it impossible to accuratelydetect if an email address is valid or not until you actually send an email to the recipient. Yahoo is an example of one such provider.
Manymailservers do not cooperate orprovide a falsepositive onpurpose. This maybe an due to a difficult admin or can be used as a form of spam management. With these domains it is difficult to determine if the email address is actually valid or not.
Since some ESP’s do not cooperate with certain checks a final SMTP connection is recommended for best results. To further enhance your data and emails which took action are reported back with a “responsive” tag. This not onlyallowsyou to remove the bottompercentage of BAD data, but identifythe top portion of GOOD data.
When our system is unable to conclusivelyverifythe status of an email address, it it marked as “unknown”. These emails mayor maynot be valid. Examples of this status can be catchall email addresses, certain soft bounce return codes, or temporarily unavailable email addresses.
AtVerifications.iowe aim toprovide the highest level of email verificationpossible, but at times circumstances are out of our control. The followingsituations arepossible issues we can encounter while verifying email addresses.
False Positives with Email Validation
In certain cases email addresses maybe marked valid and mayin fact be invalid. This falsepositive can be caused byseveral reasons. A rogue mail admin maywish to monitor traffic on his network to block users. Someproviders(free mailproviders manytimes)maydo this as apart of their anti spamprotection. In other cases invalid emails are reactivated so administrators can use them as honeypots for spammers. And finallysome systems identifyanyemail in their database as active once setup, and do not reply with the correct bounce message until you actually send a campaign.
Temporary SMTP Server Issues
The majorityof the unknown results from ouremail validation systemare caused bytemporaryissues. These may include the following reasons:
SMTP server timeout or downtime GreylistingMailbox size exceedsquota Temporarymailbox suspension Temporaryblockingdue to low IP reputation Due to these reasons it is stronglyrecommend to verifythe unknown status of the list down the road. We do not recommend deletingthe unknownpotion ofyour list immediatelyafter verification. Chances are that previous emails which previously tested as unknown are in fact valid.
GreylistingGreylisting is when a mailserver returns a temporary failure response or “temporarily unavailable” on the first attempt to deliver an email. It mayaccept it on the second attempt. A correctlyconfigured email server will attempt to redeliver a message after a temporary failure response x number of times depending on it’s configuration.
Sincegreylistingis a temporaryissue from the remote mailserver we do not recommend deletingthe unknown results due togreylisting. These “unknown” status emails mayin fact be valid as previouslymentioned.
Catchall Email Domains
Our email validation service has the abilityto detect catchall emails. A catchall email account is an address that is specified to receive all messages that are addressed to an incorrect email address for a domain. These emails may be “valid” or “invalid” but the mailserver accepts fake, nonexistent,
and valid email addresses. In some cases, these catchall domains are used byISPs and ESPs as spam traps and for spammers using dictionary spam attacks.
This makes it verydifficult to verifyif the email is valid or not on our end until a bounce replyis received. Our final SMTP feature helps in this regard or you can mail it on your end.
Email Service Providers Not FollowingProtocol
Some ESP’s do not follow normal protocol and have certain features turned off by default. This is done toprotect their network. A real email must be sent in order to trigger a response. This makes it harder to verifyif the email is valid or not. We suggest a real campaign deployment after verification to remove any last bounces you may encounter.