Xtra filter email with blank From, To or Subject
I started having problems some weeks back with Xtra mailboxes not receiving mail from a number of lists that we send. After a bit of troubleshooting our end, a query to Xtra helpdesk revealed that they now filter emails that have a blank Mail From, To or Subject field (our lists have never had a from address and our email server appears to not have the facility to add one, which kinda makes it my problem but ...). Xtra said: "We have implemented a rule on our Xtra Email Servers requiring at a minimum of a From email address, To email address, and a subject to be displayed to prevent this form of Spam. If all of these are enterred into the email this will ensure continued delivery of the automated emails. The Anti-Spam filter works by checking the content and style of email content. These blank emails have hidden content in the body that appears legitimate to the Anti-Spam filter and are passed." Not sure if this is news or not, but I hadn't seen anything publicised re this change. My understanding was that blank "from" fields are valid, so filtering this type of email may break other things such as read receipts. Has this been a problem for anyone else out there? Dave
Not sure if this is news or not, but I hadn't seen anything publicised re this change. My understanding was that blank "from" fields are valid, so filtering this type of email may break other things such as read receipts.
Blank FROM is valid? I'd have considered a Blank Subject as potentially valid, but surely the From: address should be a requirement? I see a can of worms opening here... (As much as I hate blank-content spam) Mark.
Not sure if this is news or not, but I hadn't seen anything publicised re this change. My understanding was that blank "from" fields are valid, so filtering this type of email may break other things such as read receipts.
Are they rejecting? putting in spam folder or it just disappears?
Blank FROM is valid?
I'd have considered a Blank Subject as potentially valid, but surely the From: address should be a requirement?
Well the RFC's says a few things SHOULD be included like the Message-ID,Subject,Date, but in real terms it (I think) a From: and To: header should really be included as well, but the RFC's doesn't mandate anything at all has to be in the Header or a message to be a valid Email. Saying that, people will do what they want for the "common good" and rejecting? messages with no From: Header may be good for the greater number of people. I see very little messages with blank From headers and I would think its pretty uncommon (except for spam) to have no From: header. There are many rules mail servers use to stop spam like Rejecting messages with no message-id: header, no date: header and no subject: header. a Read Receipt is a DSN so <> and should be treated a little different than a normal message and I haven't see any without a From: header. Don't get the MAIL FROM and the Header From: confused :-) RFC's are only suggestions on how things are "suppose" to work Thanks Craig
Craig Whitmore wrote:
Not sure if this is news or not, but I hadn't seen anything publicised re this change. My understanding was that blank "from" fields are valid, so filtering this type of email may break other things such as read receipts.
Are they rejecting? putting in spam folder or it just disappears?
It just disappears, no reject or moving to spam folder.
Blank FROM is valid?
I'd have considered a Blank Subject as potentially valid, but surely the From: address should be a requirement?
Well the RFC's says a few things SHOULD be included like the Message-ID,Subject,Date, but in real terms it (I think) a From: and To: header should really be included as well, but the RFC's doesn't mandate anything at all has to be in the Header or a message to be a valid Email.
Saying that, people will do what they want for the "common good" and rejecting? messages with no From: Header may be good for the greater number of people. I see very little messages with blank From headers and I would think its pretty uncommon (except for spam) to have no From: header. There are many rules mail servers use to stop spam like Rejecting messages with no message-id: header, no date: header and no subject: header.
a Read Receipt is a DSN so <> and should be treated a little different than a normal message and I haven't see any without a From: header.
Don't get the MAIL FROM and the Header From: confused :-)
Good point. The list email that is received at a non-Xtra mailbox actually displays a from address. On the email server when it is sent, the log says that the SMTP MAIL From field is blank <>. Dave
On June 22 2006 a filter was added to Xtra Email that will drop emails that have both a blank "To:" address and blank "Subject:". In order to not have messages dropped please ensure you provide as a minimum a "Subject:" or a "To:" address. Kind Regards, Ted Grenfell ISP Performance Manager T +64 9 359 5854 (extn 93254) F +64 9 377 0781 M +64 27 443 5455 E ted.grenfell(a)telecom.co.nz W www.telecom.co.nz Level 11, Telecom House, 8 Hereford Street, Private Bag 92028, Auckland CBD, New Zealand ________________________________ "This communication, including any attachments, is confidential. If you are not the intended recipient, you should not read it - please contact me immediately, destroy it, and do not copy or use any part of this communication or disclose anything about it. Thank you. Please note that this communication does not designate an information system for the purposes of the Electronic Transactions Act 2002."
-----Original Message----- From: Dave Green [mailto:dave.green(a)paradise.net.nz] Sent: Tuesday, 25 July 2006 9:14 p.m. To: nznog(a)list.waikato.ac.nz Subject: [nznog] Xtra filter email with blank From, To or Subject
I started having problems some weeks back with Xtra mailboxes not receiving mail from a number of lists that we send. After a bit of troubleshooting our end, a query to Xtra helpdesk revealed that they now filter emails that have a blank Mail From, To or Subject field (our lists have never had a from address and our email server appears to not have the facility to add one, which kinda makes it my problem but ...).
Xtra said:
"We have implemented a rule on our Xtra Email Servers requiring at a minimum of a From email address, To email address, and a subject to be displayed to prevent this form of Spam. If all of these are enterred into the email this will ensure continued delivery of the automated emails.
The Anti-Spam filter works by checking the content and style of email content. These blank emails have hidden content in the body that appears legitimate to the Anti-Spam filter and are passed."
Not sure if this is news or not, but I hadn't seen anything publicised re this change. My understanding was that blank "from" fields are valid, so filtering this type of email may break other things such as read receipts.
Has this been a problem for anyone else out there?
Dave
_______________________________________________ NZNOG mailing list NZNOG(a)list.waikato.ac.nz http://list.waikato.ac.nz/mailman/listinfo/nznog
participants (4)
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Craig Whitmore -
Dave Green -
Mark Foster -
Ted Grenfell