Validation of domain part for email addresses through DNS lookup

Question

I'm using Amazon SES where doesn't allow high bounce rate. They will suspend sending emails when the user make large amount of bounces. So I want to keep bounce rate low as possible.

So, here's my question: Is it good idea to lookup DNS MX and A record of the domain part of destination address (e.g. example.com) for every emails before sending? Is there any bad side effect of this approach? Or do you have any other better typical solution?

More information about my situation

Sometimes my customers enter wrong addresses. for example, when they seem want to enter jane.doe@example.com but sometimes it went wrong such as jane.doe@example, which .com part is missed.

In such case, bounces will be returned after 840 minutes because SES keeps email which have destination of jane.doe@example, will arguably never be delivered successfully.

The problem is, SES keeps the emails that never be delivered successfully for 840 minutes long, after that the emails will be returned as bounces, so my bounce processing mechanism which implemented as explained in https://sesblog.amazon.com/post/TxJE1JNZ6T9JXK/Handling-Bounces-and-Complaints can't get any feedback immediately. eventually, I got thousands of hard bounces, that make my bounce rate higher.

Answer 1

SES has a mechanism to handle bounces and complaints, as described in the link you reference.

You need to be validating emails when they are first submitted: if the validation email bounces, then force the user to enter another email address, and do not consider that account valid. You can add some simple validation to the domain, but keep in mind that there are hundreds of new top-level domains, so email addresses like jane.doe@bank.investements may be valid.

In addition, looking up the MX record won't help at all: most of the common "typo" domains will work, so jane@example.com and jane@exampl.com will probably both have MX records.

Update:

Remember that email originated as "store and forward": not every domain was expected to be instantly available at all times. So even your validation email may not reach the end user for several hours. The key here is that you should not send emails to an address that has not been validated. If you do this, you are potentially violating the SES terms of service, but at the very least you're opening up a channel for people to use your service to annoy people, which will have a negative impact on your bounce rate.