Deluged by Mail Daemon

[kc80027]

For the past 5 weeks, since the domain split, I have been receiving undeliverable mail messages from automated Mail Daemon, Mail Delivery Subsystem, Postmaster, etc. services. Between 5 - 10 reject messages every day. The addresses are unique subdomain addresses using my account, for example xyz @ username.fastmail.fm
The initial part of the subdomain address appears to be randomly generated letters. I never received these messages before the domain split. What's the best way to deal with this as a basic member?

[janusz]

If (repeat: if) you do not expect legitimate emails to these subdomains, do the following: Options - Define Rules - Reject and then from the appropriate drop down menus select Message with: From/CC, That: contains, The text: username.fastmail.fm
Then click Add, and finally Done (top r.h. corner)

[kc80027]

Thanks for the suggestion. The problem with this solution is that the hundreds of undeliverable messages that I have received in the past month have been sent to unique subdomain addresses. There seems to be no pattern, just randomly generated letters at the beginning, so there is no practical way of implementing your suggestion. I have considered rejecting all messages from "Mail Daemon," "Mail-Daemon," "Postmaster," "Mail Delivery Subsystem" or subject contains "returned mail," "undelivered mail," "failure notice," "expired delivery," etc., but then I will not receive a legitimate notice of a failed delivery. I am sure it is no coincidence that this started happening with the domain split, but don't know why. Don't really care that much about the why, just want to stop all these messages from coming in.

[kc80027]

janusz,
I just reread your reply and noticed you suggested rejecting text containing username.fastmail.fm . I use subdomain addressing when ordering online, like amazon @username.fastmail.fm so I think I would lose this ability if I implemented the rule as suggested.

[janusz]

There are some crossed line somewhere here...

What I assumed from your initial description is the following:
1) let's say your real address is fred@fastmail.fm
2) you receive unwanted junk sent to random_characters@fred.fastmai.fm
3) you do not use/need any addresses of the format anything@fred.fastmail.fm

If this is correct, the method I described should work, as the filter will check if fred.fastmail.fm is in the To/Cc field. Anything else in that field will be ignored.

[kc80027]

Sorry for not making myself clear.

1 and 2 are correct. The unwanted junk is undeliverable mail messages automatically sent by Mail Daemon service.

3 is incorrect. I do need to use the format anything@fred.fastmail.fm

[robmueller]

This is called "backscatter" (bounces to emails you never sent). More details here:

http://www.fastmail.fm/docs/faqparts...unkBackscatter

You can filter out 99% of backscatter just by going to Options -> Spam/virus protection, selecting Normal or Aggressive protection, and clicking Done. Even if your level is already set to Normal or Aggressive, you should click Done there again to ensure that the backscatter detection rules which were
only added a few months back are incorporated into your rules.

Rob

[adam15c]

Originally posted by robmueller
This is called "backscatter" (bounces to emails you never sent). More details here:

http://www.fastmail.fm/docs/faqparts...unkBackscatter

You can filter out 99% of backscatter just by going to Options -> Spam/virus protection, selecting Normal or Aggressive protection, and clicking Done. Even if your level is already set to Normal or Aggressive, you should click Done there again to ensure that the backscatter detection rules which were
only added a few months back are incorporated into your rules.

Rob

If you have defined your own rules how do you add the "backscatter" rule? Thanks.

[hadaso]

My Sieve script (that is produced by FastMail from my rules) says:

...
if not header :contains ["X-Spam-known-sender"] "yes" {
if allof(
  header :contains ["X-Backscatter"] "yes",
  not header :matches ["X-LinkName"] "*" 
)
...

[kc80027]

Rob,

Thanks for the reply. It looks like you have to be a Full or Enhanced Member to get these protection options. I only see a message in my settings that states basic spam protection enabled. So I guess it's back to setting rules to reject messages from Mail Daemon, Mail Delivery Sugsystem, etc. (Or upgrade.)

kc

[robmueller]

Yes, only Full/Enhanced I'm afraid. That is your other option... upgrade

Rob