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Comment by blop | Hacker News Reader

I still run my own email system (postfix/dovecot for imap), mostly for one reason: the virtual username function of postfix:

I configured postfix with:

    recipient_delimiter = .

which gives me unlimited dynamic virtual addresses (username.<something>@mydomain), so I know where spam/leaks come from if I get unsolicited mail directed to `username.<unique_name_per_registration>`, and it makes it trivial to block.

I know that you can do the same thing with google addresses using + as a delimited, but the + sign is often not allowed in dumb email checks. Also spammers probably know about + and strip it automatically anyway...

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If you're running your own server, you can just setup catch-all account and use something like $(printf %s news.ycombinator.com | sha256sum | head -c 12)@mymail.com for further privacy.

You don't need to run your own email server for this. I do this with a catch-all in Fastmail for $50/year or something. I'm pretty sure Gmail and most others can do this too.

I've been doing something with dash as the recipient delimiter since the late 1990s and it's been great. But that became a pain when I wanted to switch to hosted email, as many providers wouldn't support it.

I eventually ended up at Fastmail, as they let you build custom Sieve scripts that can do this kind of remapping without having to run your own mail server.

Love that, too! I've always been amazed that spammers aren't able (to my knowledge) to defeat such a simple scheme by removing the . or + in the local part.

Gmail works with . as delimiter as well as +

with gmail you can do:

    foo+anything  => redirected to foo
    foo.something => redirected to foosomething (so . is not the same as +)

The + isn't always accepted in dumb email checks though, and spammers know about it...

I believe you can insert dots as you wish but not use it like the plus sign. So abc@gmail.com is the same as a.b.c@gmail.com but abc.new@gmail.com is another account than abc@gmail.com.

> so I know where spam/leaks come from

unless they use BCC

Deliver to address is always in the headers, even if message is Bcc'ed to you.

that's good to know.

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