Check to see if a Recipient Domain Exists

Modified on Fri, 1 Feb, 2019 at 8:12 PM

Monday, September 10, 2018


We are changing the way that our system functions as of today.


We will be validating the To: address on outbound SMTP messages to ensure that the domain that is registered. We willl be deferring emails To: unknown Domains or domains that return NXDOMAIN to a DNS queries. Historically we accepted these messages.


Common Questions


What if there is a DNS problem resolving the sending domain?


  • If this DNS failure is transient the sending SMTP server should retry sending the message to our gateways and we will attempt to resolve the DNS record at that time. 


Why are you making this change?


  • As our system has become more popular we have noticed more and more customers sending to accidentally entered email addresses like gmail.co, hotmai.com or other commonly misspelled domains. Historically we accepted these messages but they were never delivered, now we are just going to defer the accepting of these messages and the sender should notice in their queue that these messages are deferred. 


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