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spamassassin: TO_NO_BRKTS_PCNT To: misformatted + percent

Do any of you spamassassin experts out there know what TO_NO_BRKTS_PCNT is? I have not been able to locate a description of this rule and it does not appear in the official list at http://spamassassin.apache.org/tests_3_3_x.html.
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Tony Giangreco
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1) The To: address was badly formatted. It proably had no brackets <> which are usually around the receiver name.

2) The mail was send from a client machines without a smart host email server between. Direct connection from a dynamic IP address to the receiver's MX server.

http://www.gossamer-threads.com/lists/spamassassin/users/159892
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Mark

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Thanks for the quick response! Good find on that link. I couldn't find a description.

It is true that the To: address had no brackets. It is of the form:

To: user@domain.com

but since when are brakets "required" in a To: address? I send to peoples' plain ole email addresses all the time, and I've email to this particular user daily ever since spamassassin was installed last April.

> 2)The mail was send from a client machines without a smart host email server between. Direct connection from a dynamic IP address to the receiver's MX server.

Not sure about this. The sending machine definiately has a static IP, but the IP probably doesn't match the MX record. The sending linux host goes directly via SMTP, but gets mail via POP from a mailbox on Network Solutions (which is where the MX record points). Maybe that is what situation #2 is about? But again, the target domain is my main client and I send dozens of message daily there, from the same host. Doesn't make sense.

3.0 is a pretty stiff score for this!

The body of this particular email had a percent-sign in it. Could that be part of the problem?
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ASKER

I was hoping for a little more insight on this. The vast majority of emails I send don't have brackets in the To: address and I don't see any spam score for that. Any idea what the TO_NO_BRKTS_PCNT check might really be checking for?
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Sudeep Sharma
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SSharma: >I would like to mention that first RFC Standard for SMTP RFC 821 doesn't require that recpient email address should have < >.

Interesting. I am using a "Legacy" mailx version 12.4 client on Linux and it apparently does not add the brackets. I'll have to keep this in mind for the future.
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ASKER

Thanks for the clarification. That's what I was looking for.
Just to note that the accepted answer is simply wrong; it's the correct answer to a different question. The question is about the "To" address header within a mail message. RFC 821 and 2821 are SMTP standards, not message format standards. The SMTP `RCPT TO` command does require angle brackets around the address, but that has absolutely nothing to do with headers within messages, which SMTP pays no attention to. The address specification used in message headers is defined in RFC5322 section 3.4 which says:

There is an alternate simple form of a mailbox where the addr-spec address appears alone, without the recipient's name or the angle brackets.

In short, it is entirely valid to omit angle brackets around email addresses in message headers.
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ASKER

Squinky: Thanks for that. I'm going to experiment with specifying brackets or not today to see how all this works.