Bouncing emails preferred method
 

Here's a quote from Bill from 2014:

If you have a wildcard target set up, you can also set up other targets. The wildcard will only be used if no specific aliases are found.
If a virtual alias targets itself, that address won't exist. So if you enter nemo@mydomain targeting nemo@mydomain, messages sent to that address will generate a bounce (as if the address does not exist). This will happen even if the wildcard alias is active, and is one way to block certain addresses at your domain?


Is this still the preferred way to block a particular alias when you have a wildcard at your own domain? For example, I get spam at paypal@mydomain.com. Should I create an alias where paypal@mydomain.com targets paypal@mydomain.com to bounce it? Should this alias come before the *@mydomain.com targeting my Fastmail address, or after?

Or is there a better way? Thanks.

As far as I know, Bill's recommended solution is still the best. The order of the aliases will not matter. Regardless of where it exists in the list, the wildcard alias is always processed last.

I would have thought you would have to do every alias individually otherwise surly you would block the whole domain.

When you say "bounce" I hope you mean "reject". Bouncing means to discard a message and send a delivery status notification to the sender. For spam this can mean sending unwanted backscatter if the sender address is forged.

Thanks for the correction - I definitely mean reject, so that I no longer get email to a specific alias at my domain.

An alias can be directly set to be blocked
 

Yes, I made that post. See:
https://www.emaildiscussions.com/showthread.php?p=568760#post568760

But that was over six years ago, and Fastmail has greatly changed over that period. Now there is a direct way of disabling a particular alias at your domain:

• Go to the Aliases screen.
• Edit the alias you wish to block.
• Enable this setting for that alias:
  Quote:

  Reject (bounce) all mail sent to this address (disable the alias) Disable a specific address when you have a wildcard (catch-all) alias.

If messages arrive for that alias, it will appear that it does not exist. This does not generate a "bounce" email to the From address. Instead, that particular alias no longer exists at the domain, so the sending email server will typically generate a 550 SMTP error such as:

After blocking certain aliases in this manner from a domain with a wildcard alias, there are three possible conditions:

• Messages sent to aliases which are blocked in this manner will generate a 550 SMTP error, since that email address is invalid. This error will appear in the sending server and will not bother any spoofed From address set by a spammer.
• Messages sent to listed aliases which are not blocked will be delivered to the delivery address specified in the alias screen.
• Messages sent to any other alias will be delivered to the Inbox (unless a rule or plus or subdomain address changes the target folder).

I hope this helps. There is no need to use that old trick I described many years ago before the alias feature was improved.

Bill

Thanks so much Bill - glad I asked. I also want to thank you very much for all the great information and assistance you've provided over the years - you've helped me immensely.

You are very welcome. Fastmail has improved their service greatly in the last few years and now it is unusual to require use such "tricks".

Bill