EmailDiscussions.com - how to define a bounce rule?

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how to define a bounce rule?

I am a new user to fastmail, and still exploring it's capabilities. So far, very impressed. I am hoping to be able to bounce an email, rather than simply discard it.

It appears that this is possible in the Large emails section of Rules -- I'm guessing that what "reject" means there, as opposed to the "discard" elsewhere in Rules.

Specifically, I would like to use a catchall address, but then reject specific addresses.

Perhaps it can be accomplished using the Sieve language?

Any tips would be greatly appreciated.

Thanks!

Quote:

Originally Posted by makani (Post 571356)

Welcome to the forum, makani.

I'm not a sieve expert, but this works for me:

Code:

require ["envelope", "imapflags", "fileinto", "reject", "notify", "vacation", "regex", "relational", "comparator-i;ascii-numeric", "body", "copy"];

#

#

if header :contains ["From", "X-Mail-from", "Return-Path"] "_____@_____" {

  reject "Message rejected because ___________!";

  stop;

}

#

#

I do not use it as a Spam filter, but only to reject messages from known senders whose mail I no longer wish to receive.

Not sure about the wisdom of setting-up a catch-all account, I assume you have your reasons.

However, if you use "reject" sieve rules as a Spam filter, you'll be creating a lot of so-called "back scatter" that may cause the IP address from which reject messages are sent to be listed on an RBL, and will certainly get you in trouble with Fastmail management.

By the way, I believe, but I'm not sure, that you can only use custom sieve rules with "Enhanced" and "Premier" accounts.

Good luck.

--
Jacinto

Quote:

Originally Posted by makani (Post 571356)

I also use catch-all for my domains, but slowly, I'm eliminating all unused, unwanted and spammed aliases built up over the years. I use the discard function rule to filter these out.

Jacinto is right, once you start bouncing emails, it can get messy.

Thank you both for the speedy responses, they were very helpful!

I guess I will just stick with discarding things for now. It just makes me a little sad inside to have spammers get their email delivered instead of bounced.

The reason for the catchall is so I can give a unique email address to every different website where I register. My thinking with the bounce was to block a specific destination address that I had given out, if it starts getting used for spam -- which has happened with a few addresses. I would rather not encourage spammers in the slightest.

I could of course go the route of adding an alias for every website instead of having a catchall, and that would do what I'm wanting, but take a lot more effort. I have lots of websites where I register (don't we all), and more added all the time, whereas I only have a few addresses that need blocking. Perhaps one day that will reverse and I will have more addresses that I want to blacklist than I want to receive at, and then of course this would be the obvious route.

Hopefully my goal is clear. If anyone has any suggestions on how to accomplish this, happy to hear them.

Thanks again.

The best solution for you, is to use a catchall for your domain, but disable individually the smaller number of addresses you do not want to exist. Rather than write filters to reject these addresses, simply put entries for them in the list of domain addresses, and have each one target itself. For example, if you want newslettr5(at)mydomain.com to be blocked, put an entry in for that address and have itself as a target, i.e., newslettr5(at)mydomain.com. Mail to this address will be refused at the Fastmail gateway (smtp stage), so there is no danger of sending a bounce back to an innocent party impersonated by a spammer. There is a extra step required if you use "Force Ext" for your domain. See the discussion at Create a CatchAll account to my Custom Domain, starting at post #3, and pay attention to post #7 if you use "Force Ext".

This is what I have been doing. But note that if you are unfortunate enough to be a victim of spam to random wildcard addresses to your domain, rather than specific addresses you once used, this will not be effective. This happened to me for nearly a year, but it seems to have almost died out now.

Quote:

Originally Posted by makani (Post 571372)

. . .

I guess I will just stick with discarding things for now. It just makes me a little sad inside to have spammers get their email delivered instead of bounced.

That would be a wise choice -- especially since new accounts are watched for unusual activity (and suspended or deleted if necessary).

Quote:

Originally Posted by makani (Post 571372)

The reason for the catchall is so I can give a unique email address to every different website where I register. My thinking with the bounce was to block a specific destination address that I had given out, if it starts getting used for spam -- which has happened with a few addresses. I would rather not encourage spammers in the slightest.

Although Fastmail's Spam filters are not perfect, they are adequate for most users.

What is good about them is that you can actually build up your own Spam Assassin corpuses of Spam and Ham messages. Once you have classified 200 of each, there is a setting that tells the Spam filters to use your corpuses.

By the way, you can classify Ham messages even if they are not false positives.

--
Jacinto