Ask HN: How to check if e-mail belongs to a “work” domain?

akg_67 · on May 11, 2015

It is not "stupid", it is simple and effective. I use the blacklist process to exclude disposable email domains (there are 100s of them and everyday new ones come up) from registering on my service. It is much faster and inexpensive than making a round trip API call to some remote service to confirm validity of the email domain.

Unless you don't have better things to do with your time, I will suggest focusing your time on things that are more important.

victorstanciu · on May 13, 2015

Ditto. And since akg_67 didn't link to one, here is a great disposable email domain list:

https://github.com/ivolo/disposable-email-domains/blob/maste...

New domains are added to the list via pull requests.

murtza · on May 12, 2015

If you are doing this verification on the client-side, you can restrict form submissions when a user enters a free email address like Gmail or Yahoo.

Here's a post I wrote with an implementation of this approach (specific to Marketo forms, but can be made generic for any form): http://developers.marketo.com/blog/restrict-free-email-domai...

I would also recommend labeling the email address field on the form, "Work Email."

fragmede · on May 11, 2015

For really big corporations that own their own netblocks, the listed whois owner's email address should match the domain name entered, but that fails on domains that use Google for their mail. (Ie 'gmail.com' lists an @google.com contact which doesn't match the domain name.)

Just start with a blacklist for the big ones, and then manually opt-in domains after a look at a domain's webpage under pg's "do things that don't scale" mantra.

nailer · on May 11, 2015

Wouldn't

whois 'domain foo.com'

likely return an admin contact at foo.com even if they're using Google Apps?

panorama · on May 11, 2015

Blacklisting is an okay option, but as you said, it's tough to do so just going by your memory. In fact there are actually thousands of free, public domains, which you will likely want to blacklist. Here's a good list (2013):

https://gist.github.com/tbrianjones/5992856

P.S. Maybe someone should make an API to verify if a domain is free/public or not :)

Nadya · on May 11, 2015

Why does your solution "feel stupid"? It's the most straight forward and workable solution.

You have two options:

a) Whitelist all domains you want (if you only want specific 'work' domains)

b) Blacklist those you do not want

duroth · on May 11, 2015

It "feels stupid" because I don't want to allow any sort of generic domain and off the top of my head I can think of 20 generic e-mail domains, not event counting the ones I don't think of.

In the situation I need it in, that's an OK solution, but I was interested in finding out if there exists a better solution.

theaccordance · on May 11, 2015

There's an off chance you could do an extra level of verification using the mail headers, but I wouldn't bet on it. Keep in mind that email is an old technology, it lacks a lot of things that would make it more efficient/useful in 2015

nailer · on May 11, 2015

Bayesian filtering. Add points for things that seem personal, set a threshold of points.

This is how, eg, anti spam often works.

ivankirigin · on May 11, 2015

What is the context? I help do this kind of analysis over a user's contacts as part of YesGraph.

duroth · on May 11, 2015

I am building a product that works automatically for all the people "inside" an e-mail domain. So everybody that's a part of @yesgraph.com would have access to all of the content from other people with the @yesgraph.com e-mail address.

ivankirigin · on May 11, 2015

I'd recommend just asking the user to confirm the email domain they care about. I solve this on YesGraph's registration page indirectly just by making the entry field label "work email". https://www.yesgraph.com/signup/