Aliases and catchall

[acecco02]

Hi all, I'm a new customer of Fastmail.

I was reading their article on Aliases and catchall here and I thought to put it in practice to organise my emails.

I've created a catchall and started providing personalised email addresses to my contacts (for example, bankname@mydomain.com to my bank, netflix@mydomain.com and so on) and I have also created some rules and labels.

What's the difference between a catchall and using for instance anything@user.mydomain.com - is this a sort of catchall itself?

Is this the way the service is meant to be used? I've been reading some articles online advising against catchalls because of spam.

Fastmail features are so powerful and I'm not sure what would be the best way to organise my emails.

Thank you for your help!

[n5bb]

Welcome to EMD Forums and to Fastmail! Fastmail is very flexible and there are several ways to achieve your goals.

I just wrote about this in the following posts:

• https://www.emaildiscussions.com/sho...89&postcount=3
• https://www.emaildiscussions.com/sho...01&postcount=7

I use what I believe you now have: My own domain hosted at Fastmail with the wildcard alias *@mydomain.com set up in the Aliases table to deliver messages sent to any alias at my domain to my Fastmail Inbox. If you do this, be sure you have wildcard MX records at your domain DNS for *@yourdomain.com or you won't be able to use subdomains for your personal domain.

But I don't depend on this wildcard, and I have specific aliases set up for each alias I want to use at my domain. The only reason I have the wildcard alias enabled at this moment is for testing purposes, so I can see how much random alias spam to my domain arrives. This has been significant in the past, but at this time nearly all such spam is either rejected at the SMTP stage (before you can possibly see it) or by the Fastmail spam filter. In a few cases I block a sender or add a rule in the Filters & Rules screen, but it's rare that this is required.

As I described in the post I referred to above, I normally use subdomain addressing for signing up at services. I either use a Fastmail domain alias I control or an alias at my personal domain. My feeling about use of certain addresses and a personal domain is:

• If you are signing up for some service which requires an email address to contact you, I want to use an email address which is specific to that service so I can easily disable it if it's abused and I can tell if there is a security breach which releases that special address to spammers.
• So for services where I'm filling in a form but a human will probably never see the email address, I always use a unique subdomain address since I can create any number of these immediately on the fly without going to the aliases screen. Since no human will probably see this address, I usually use an alias at a short Fastmail owned domain to create the subdomain.
• If I'm giving someone an address in person or on the phone where a human will see the address and may want to associate it with me in some cases, I use an alias at my personal domain. This is because my personal domain uses my last name, so it's these are personal identifying addresses to me.
• For example, I'm a member of the National Space Society and get space-related email from NSS, NASA JPL, and other sources. If I'm giving out my space related email address for personal email, I use "space@mydomain.com". I can also use subdomain addresses such as "JPL@space.mydomain.com".

As I point out in the threads I reference above, one advantage to using a unique alias for each service is so you can easily disable that alias if needed. But that requires a huge number of aliases over time if you use many services, so I recommend use of subdomain aliases when signing up for services.

Bill

[barmadrid]

Originally Posted by n5bb

As I point out in the threads I reference above, one advantage to using a unique alias for each service is so you can easily disable that alias if needed. But that requires a huge number of aliases over time if you use many services, so I recommend use of subdomain aliases when signing up for services.
Bill

Bill, what if I want to reject everything at SMPT level other than my currently created aliases?

For example, deny everything sent to *@mydomain.com as this address does not exists.... other than: service1@mydomain.com, service2@mydomain.com, ..... etc. (which I already created the aliases for).

Can I achieve this by creating a reject setting for alias *@mydomain.com?

[n5bb]

Originally Posted by barmadrid

Bill, what if I want to reject everything at SMPT level other than my currently created aliases?

For example, deny everything sent to *@mydomain.com as this address does not exists.... other than: service1@mydomain.com, service2@mydomain.com, ..... etc. (which I already created the aliases for).

Can I achieve this by creating a reject setting for alias *@mydomain.com?

No --- you just do not use a wildcard alias for your domain. Then only the specific aliases you enable will receive messages. Email arriving for other addresses will be rejected at the SMTP level. If you add the wildcard alias then set it to reject mail, then all mail sent to your domain will be rejected. That's not very useful!

If you have the wildcard alias enabled for your domain, you can disable specific addresses by creating aliases for those addresses, but in the alias settings set them to "Reject (bounce) all mail sent to this address (disable the alias)".

Bill

[acecco02]

Thank you Bill, very useful!

I've just noticed the following:

- I currently have only one user, myself: firstname@mydomain.com
- I have now deleted the catchall
- I have now set up several aliases e.g. netflix@mydomain.com, and a more generic one mail@mydomain.com

I noticed that the subdomain technique (anything@user.mydomain.com) works also for aliases (anything@alias.mydomain.com), which is great as I don't need to set up another user. I could not see this in the Fastmail documentation.

For example, considering the above address, the following one also works: netflix@mail.mydomain.com - even thought 'mail' is not a user, but just another alias.

[n5bb]

Originally Posted by acecco02

... I noticed that the subdomain technique (anything@user.mydomain.com) works also for aliases (anything@alias.mydomain.com), which is great as I don't need to set up another user. I could not see this in the Fastmail documentation...

From the Fastmail help page on subdomains:

For most users, you don't need to set up anything extra to create these addresses. They work right now, for both your username@domain.tld address and any aliases you have set up, both on Fastmail domains and any personal domains.

For users who have pointed their custom domain to Fastmail using MX records only, there may be additional setup needed for subdomains. See here for more details.