Incoming message size limit

[chrisjj]

Can I set a limit of incoming message size, such that messages exceeding are bounced, ideally witout using my bandwidth?

Thanks.

[janusz]

Options, Define Rules, Reject and then set your limit in Large Emails (bottom of page).

[chrisjj]

Originally Posted by janusz

Options, Define Rules, Reject and then set your limit in Large Emails (bottom of page).

Aha, that was hidden here by Advanced Rules* but temporarily reverting and following your steps gets me:

if size :over 1024K {
  fileinto "INBOX";
  stop;
}

to be pasted into Advanced Rules.

Thanks Janus

Chris

* I have had to switch to Advanced Rules (sieve script mode) to implement the fowarding non-spam workaround for the problem:

http://www.fastmail.fm/help/spam_vir..._checking.html

Note that not all headers may be added on each message. No X-Spam headers are added if the message is not spam checked because:

The user has only 'Basic' spam protection enabled
It's great than 1.2M in size (may change in the future)
A message was detected as containing a virus

[Sherry]

Hi chrisjj,

Just a couple of thoughts on what you're trying to do...

Originally Posted by chrisjj

Can I set a limit of incoming message size, such that messages exceeding are bounced, ideally witout using my bandwidth?.

Unless things have changed sieve scripts are not checked until after FM receives the incoming mail so I believe you would still be using bandwidth on those incoming emails.

* I have had to switch to Advanced Rules (sieve script mode) to implement the fowarding non-spam workaround for the problem:

I'm not sure how it works as I've never needed it but I believe the beta server has a way to put in advanced scripts without making you change to using the advanced page on the regular server. After using the beta server to write it you could go back to the regular server and the script should still work fine. Someone else would need to give you more info on how it may work with the kind of script (size) you're using.

https://beta.fastmail.fm/

Sherry

[chrisjj]

Originally Posted by Sherry

Unless things have changed sieve scripts are not checked until after FM receives the incoming mail so I believe you would still be using bandwidth on those incoming emails.

Thanks. Any solution? AFAICT currently any Fastmail account is wide open to an illwisher consuming its bandwidth.

Originally Posted by Sherry

I'm not sure how it works as I've never needed it but I believe the beta server has a way to put in advanced scripts without making you change to using the advanced page on the regular server. After using the beta server to write it you could go back to the regular server and the script should still work fine.

Thanks - I'll wait for gamma

[rblon]

Originally Posted by chrisjj

Thanks. Any solution? AFAICT currently any Fastmail account is wide open to an illwisher consuming its bandwidth.

Sure, but what is the point of that kind of "attack"? It doesn't seem a realistic threat, especially as there are cost for the attacker as well (even if he has a botnet at his disposal).

Are you trying to block spam, or email from people you know who sometimes attach large files?

[chrisjj]

Originally Posted by rblon

Sure, but what is the point of that kind of "attack"?

DoS.

Originally Posted by rblon

It doesn't seem a realistic threat, especially as there are cost for the attacker as well

No costs I can see - apart from a little time.

Originally Posted by rblon

Are you trying to block spam, or email from people you know who sometimes attach large files?

Both.

[rblon]

Originally Posted by chrisjj

DoS.

But if there is Denial of Service - FastMail will act. I had the impression you have concerns regarding the bandwidth limit measurement.

Originally Posted by chrisjj

No costs I can see - apart from a little time.

There are cost sending large attachments - just as there are cost receiving. I guess I wasn't clear about the botnet comment - I wanted to imply that if you have control over such a thing, that comes at a price (which you perhaps only will realize when the Feds walk in).

Originally Posted by chrisjj

Both

How often do you receive attachments from people you don't know? What kind of size?

[chrisjj]

Originally Posted by rblon

But if there is Denial of Service - FastMail will act.

Fastmail will automatically act to reject incoming mail, and I see no way they can manually act to avoid that including legit mail.

Originally Posted by rblon

I had the impression you have concerns regarding the bandwidth limit measurement.

My concern here is only the effect of that hitting the limit.

Originally Posted by rblon

There are cost sending large attachments

Not to the attacker using e.g. Gmail.

Originally Posted by rblon

I guess I wasn't clear about the botnet comment

Attacker does not need a botnet.

[Terry]

try this...just adjust your size

if size ver 6144K {
discard;
stop;
}