"Enter a valid email address."

"Per-recipient" email addresses and disposable email addresses are frequently used for account sign-ups and forced sign-ups. ESPs providing account "sign-up" software frequently attempt to block these.

If a disposable email address is temporary, the objection may be valid; however, it is increasingly common for "Per-recipient" (or dedicated) email addresses to be flagged as "invalid". The obvious reason is the business' sign-up software is provided by ESPs who want to harvest these addresses for spam purposes.

The subscribed entity (business) may also have an interest in blocking dedicated email addresses because a dedicated email address is a dead give-away of the source of harvested email addresses. If your receive spam at a dedicated or "Per-recipient" address, you obviously would know where they got that email address.

There are three ways ESPs handle these "Per-recipient" and similar email addresses:

1. Limit "sharing" (selling) email addresses to recipients who affirmatively "opt-in" to email address "sharing". (That's ideal.)
   
   
2. Blacklist "Per-recipient" and similar email addresses from "sharing". (That's also a good thing.) My experience is it's rare to receive spam, especially targeted spam, sent to a Spamgourmet address.
   
   
3. Block sign-ups that use "Per-recipient" and similar email addresses.  ←That's what this page is about.

But... The technique of blocking sign-ups is also the weak point.

It's generally possible to bypass email address blocking.

This page addresses actively used with an account. If the purpose is to sign-up and basically ignore all email, it is easy enough to set up a junkmail account with one of the familiar free email services (gmail, yahoo.com, etc.) and only check it when needed (e.g., verification emails).

There are several logistical problems with blocking "Per-recipient" email addresses:

1. The "new account" sign-up software is programmed for initial sign-ups, but typically not used for other transactions.
   
   
2. The blacklists frequently change. If an existing subscriber's email address becomes blacklisted (after having been subscribed), blocking the email address would have the effect of making part of the client's existing customer accounts non-functional.
   
   
3. Disabled accounts generate "customer service" calls to the client company.
   
   
4. The client business, and especially their IT departments, have little or no interest in facilitating in the blacklisting of dedicated email addresses. (Most are familiar with these dedicated addresses and many use them themselves.) It is also likely that someone in customer service will be able to bypass email restrictions because their IT department has no interest in enforcing these blacklist restrictions.
   
   
5. The sign-up software and account maintenance software are often separately developed and separately maintained.
   
   
6. ESPs and companies distributing new account sign-up software face practical limitations on which domains they can block. For example if they block gmail, hotmail (outlook.com) and yahoo, they would block too many potential users. (They also can't block dynamic IP addresses for the same reason.)

It is therefore common to be blocked from using a blacklisted (but otherwise valid) email address on sign-up, but then be able to change the email address after sign-up to that same blacklisted email address.

Bypassing email address blocking HOWTO

There are two ways to bypass blocking of "Per-recipient" email addresses:

1. Sign-up with a non-blacklisted email address and then (after the sign-up) change the email address in the "account settings" menu.
   
   
2. If your "Per-recipient" email address is blocked, ask customer service to enter the email address at their end. If they question the email address, just let them know the purpose is to identify spam sources and to protect your email integrity.

These two techniques seem to work with most sign-up accounts.

That's it. (The rest is rant.)

They're not really "disposable email addresses"

They're "dedicated" or "per-recipient" email addresses, which is why ESPs hate them. That's also the reason for using those email addresses. The subscribed entity (business) may also have an interest in blocking dedicated email addresses because a dedicated email address is a dead give-away of the source of harvested email addresses. In other words, the script "We didn't provide it" is directly contradicted if "We" is the only entity who has that particular "Per-recipient" email address.

Some dedicated email services allow the user to redirect the email to a new provider, so the dedicated email can be more permanent than one linked to a specific internet provider.

site first posted 12-Mar-2014   rev 12-Mar-2024. copyright 2014, S. Protigal

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