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Check If Email Exists

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Re: Check If Email Exists

#111

Post by johntash »

mtnGoat wrote: post #37

Except if you try this with any real volume to most hosts, they’ll block you. These same techniques are used to dictionary attack as well. Also, just because I have a catch all on my domain really shouldn’t be justification for saying my email isn’t valid and is a good way to lose business.

> Also, just because I have a catch all on my domain really shouldn’t be justification for saying my email isn’t valid and is a good way to lose business.

Agreed, 100% of the e-mails I use to sign up for services go to a catch-all.

Re: Check If Email Exists

#112

Post by neeleshs »

wyager wrote: post #91
tlogan wrote: post #86

Earlier quoted context omitted.

Not really: but majority of spammers think that they are doing marketing.

I've never once received a "marketing email" that wasn't spam.

Used to be in the same camp, before starting my own company. While the border is thin, it is clear, and there is a difference between marketing and spam.

Re: Check If Email Exists

#113

Post by jefftk »

smileysteve wrote: post #4

The SMTP way of checking if an email exists is on the wrong side of CANSPAM, beginning the sending process to check an address is specifically addressed. And this assumes you didn't systematically "guess" the address.

Where do you see this in the law? I just skimmed through it, and I'm not seeing where it's addressed?

Re: Check If Email Exists

#114

Post by femto113 »

profmonocle wrote: post #105
Cyberdog wrote: post #8

Could someone spell out a use case for this? One that comes to mind would be validating that a mailing list doesn't have any outdated email addresses in it, but couldn't that be determined by just checking for a bounce when a message is sent to it? I tried to sign up for SiriusXM the other day, and though I could create an account with my .pro email address, I couldn't actually sign up for service with that same addr…

A non-marketing example: We were onboarding a large new client to our SAAS product. This process involved creating accounts for all of their employees (tens of thousands) and sending emails with an activation link. (Where they'd be able to set up their password.) Our system sends these emails in batches, and as soon as the first batch went out we got an alert from our monitoring system that our bounce rate was surgin…

If they're checking using SMTP's VRFY command then it's actually considered a best practice for the server to always reply with a 252 "cannot verify" since otherwise it can be used to fish for valid addresses.

Re: Check If Email Exists

#115

Post by irjustin »

Cyberdog wrote: post #8

Could someone spell out a use case for this? One that comes to mind would be validating that a mailing list doesn't have any outdated email addresses in it, but couldn't that be determined by just checking for a bounce when a message is sent to it? I tried to sign up for SiriusXM the other day, and though I could create an account with my .pro email address, I couldn't actually sign up for service with that same addr…

Ideally you don't want to send an email only to find out it doesn't exist, in terms of marketing.

Do that too often and servers can start black listing your domain/IP because it looks like you're "scanning" for available email addresses.

Re: Check If Email Exists

#116

Post by benlivengood »

Semaphor wrote: post #103
wyager wrote: post #91

Earlier quoted context omitted.

I've never once received a "marketing email" that wasn't spam.

That’s you (and the large part of HN who doesn’t know anything about normal users). When GDPR came into effect, we even had people write us that they were annoyed having to reconfirm, as obviously they still wanted our newsletter.

Some people want to receive marketing emails. The exact same emails are spam to the rest of us. If you default opt-in users and don't make blanket unsubscription from all marketing emails easy (and make the clear distinction [both internally and externally] between emails regarding the existing functionality of products/services that we've already paid for and emails to ask for more revenue from us, which includes copy supported by advertisers), then you're a spammer, simple as that.

Spammers aren't necessarily evil, but definitely annoying, and annoying customers is a good way to lose them. It's easy to drink the coolaid and eat the dogfood when you're paid to like it or have a passion for creating it but potential customers have roughly the opposite incentive and it pays to remember that.

I receive a lot of unread, unwanted email from companies I pay money to every month. It's ridiculous.

Re: Check If Email Exists

#117

Post by DistressedDrone »

user3939382 wrote: post #25
gh2k wrote: post #21

I hope nobody uses this for anything serious. I run my own domain and use - @ to have a unique email for everything I sign up to. I have no email address that this counts as anything other than "risky". If this opts me out of marketing mail then that's probably a good thing, but I hope nobody puts a password-reset or security/billing notifications behind it.

I’ve been doing the same thing for years and haven’t had any trouble except for Mailchimp. Their overly-clever validation decided mailchimp@example.com is a shared email account (it wasn’t going to be) and blocked me from using it. Their email support apologized but said they couldn’t fix the false positive, and that they hoped the email I used instead wasn’t reflective of my opinion: mailchimp-morons@example.com.

Why would that even be a problem?

Re: Check If Email Exists

#118

Post by prashantsengar »

rudyfink wrote: post #22
gh2k wrote: post #21

I hope nobody uses this for anything serious. I run my own domain and use - @ to have a unique email for everything I sign up to. I have no email address that this counts as anything other than "risky". If this opts me out of marketing mail then that's probably a good thing, but I hope nobody puts a password-reset or security/billing notifications behind it.

Would you mind sharing your experience on how well that has worked for you? Has the complexity of maintaining different addresses been a problem? I ask because it is something I have always thought about, but I suppose I kept hoping a service would come along and magic the solution for me. Kudos on making it happen!

I use anonaddy for this. A generous free plan, really feasible paid plans, and is open source so you can self-host it as well.

Re: Check If Email Exists

#119

Post by bkuehl »

profmonocle wrote: post #105
Cyberdog wrote: post #8

Could someone spell out a use case for this? One that comes to mind would be validating that a mailing list doesn't have any outdated email addresses in it, but couldn't that be determined by just checking for a bounce when a message is sent to it? I tried to sign up for SiriusXM the other day, and though I could create an account with my .pro email address, I couldn't actually sign up for service with that same addr…

A non-marketing example: We were onboarding a large new client to our SAAS product. This process involved creating accounts for all of their employees (tens of thousands) and sending emails with an activation link. (Where they'd be able to set up their password.) Our system sends these emails in batches, and as soon as the first batch went out we got an alert from our monitoring system that our bounce rate was surgin…

I can't even imagine wanting to handle managing accounts and credentials for that many users at an enterprise! At that point SSO integration is well worth the money. How did you handle removing access when a user was no longer employed at the company?

Re: Check If Email Exists

#120

Post by Semaphor »

benlivengood wrote: post #116
Semaphor wrote: post #103

Earlier quoted context omitted.

That’s you (and the large part of HN who doesn’t know anything about normal users). When GDPR came into effect, we even had people write us that they were annoyed having to reconfirm, as obviously they still wanted our newsletter.

Some people want to receive marketing emails. The exact same emails are spam to the rest of us. If you default opt-in users and don't make blanket unsubscription from all marketing emails easy (and make the clear distinction [both internally and externally] between emails regarding the existing functionality of products/services that we've already paid for and emails to ask for more revenue from us, which includes co…

I agree with all you said. But there are many comments on HN that are "all marketing is spam in general".
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