Hi,firstly, thanks for such a nice product.

Now, admittedly i've only just downloaded and started to configure it, but there seems to be a feature i was looking for, missing, or it just not obvious (to me) how to accomplish it.


I was hoping to have the system configured so that it ran in the background/minimised, and would automatically respond, with a custom NDR to all emails, not in my friends list. The custom NDR that it responds with would be something along the line of..(the NDR "mail from" address would need to be prefixed with NoReplies_ , to stop any potential mail loops)


Hi {sender},
You tried to contact {recipient},
That mailbox is protected by Mailwasher Pro, and as such, your email has NOT been delivered, as you are NOT a known sender. To become a known sender, please include in the subject line of your email , the last 6 digits of {recipient}'s cellphone number. This 'keyword' will identify your email address as a trusted friend, and will ensure that all future emails from {sender} will be delivered to {recipient}'s inbox.

Mailwasher would need to contain a small list of key-word(s) that it would then use to self-authenticate inbound emails.

Can/Does Mailwasher Pro offer such a feature?

Nope.

The problem with such a system is the spurious NDRs sent to who-knows-where. Spammers typically forge the From address so those NDRs might end up at someone's email account who gets annoyed with such msgs. Such a person might well promptly report the msg and get your ISP blocklisted. Your ISP might not be very nice when requesting that you cease and desist the practice.

Since 90% of spam has forged return addresses all this feature would do is assist the spammers in attacking folks by flooding their inboxes with bogus bounces and misdirected challenges.

The only way a message can be safely rejected is by the mail server and then only before it is accepted for delivery.

There is more on this in the wiki.

http://wiki.castlecops.com/What_is_Wrong_With_Bouncing_Spam

Thanks for your responses. Point taken...

Ok, so dropping the NDR "bounce" part of the idea... is it possible to still have people include a "key-word" in the subject field, to aid in MW auto-populating the friends list ?

eg i might therefore have instuctions on my business cards, telling people to include such a code-word on their 1st email.

For sure. Go for it. Just set up a MWP filter and even add a sig at your email client that reminds folks what they should do to make sure their email gets through the blockade.

Will a message that gets through the MWP filter, cause that senders email addr to be added to friends list, for all future emails, or they must remember to add the "keyword" each and every email ?

You need to add them to the friends list on your copy of MW, not sure if it can be done automatically by other tools or not.

If you send someone an e-mail you can include the keyword in your signature if you are downloading enough lines that it would normally be present when someone replied to your message.

If you want more protection than the friends list offers you can do a filter that looks at the whole from line to include the name and filter on that. A bit time consuming but it eliminates a lot of spam that forges good addresses. I do that for news letters and such that are commonly forged to spoof folk's friends list.