blacklisting local domain?

Julian Field MailScanner at
Tue Jan 13 19:19:47 GMT 2009

On 13/1/09 19:06, Denis Beauchemin wrote:
> Julian Field a écrit :
>> Oops, sorry, just thumped "send" by mistake.
>> Take 2:
>> MailScanner itself always uses the envelope sender address, and not 
>> the From: address which is what you are looking to check.
>> So you would have to do it with a SpamAssassin rule, as that is the 
>> only thing which can be told to look at the From: address.
>> So you want to check for mail which doesn't come from your IP space 
>> but does contain your domain in the From: header.
>> I haven't got an instant solution to that, but can you confirm that I 
>> have summarised the problem correctly?
>> Could we do it with a SpamAssassin Rule Actions ruleset, and an SA 
>> rule which looks for your domain appearing in From: ?
>> SpamAssassin Rule Actions = %rules-dir%/sa.rule.actions.rules
>> sa.rule.actions.rules contains
>> From: 152.78.71 NON_EXISTENT_RULE=>deliver
>> FromOrTo: default MY_DOMAIN_IN_FROM=>not-deliver,store
>> spam.assassin.rules.conf contains an addition
>> header MY_DOMAIN_IN_FROM From =~ /\$/i
>> score MY_DOMAIN_IN_FROM 0.01
>> describe MY_DOMAIN_IN_FROM My domain name appears in the From: header
>> The SA rule "NON_EXISTENT_RULE" does not exist, it just needs to be 
>> in the sa.rule.actions.rules file as a dummy.
>> The sa.rule.actions.rules file says
>> If it's from my network (152.78.71 in this example) then we don't do 
>> anything special (the rule name does not exist so can never fire so 
>> the "deliver" action will never be executed here).
>> If it's from anywhere else, and my domain name ( in this 
>> example) appears in the From: header, then store a copy and don't 
>> deliver it to its original recipients.
>> The score of 0.01 is just some very small number as you don't 
>> actually want to greatly affect the spam score, but you do want the 
>> rule to be checked so it can't be zero. -0.01 might have been a 
>> better choice.
>> I think that should work.
>> You can do almost anything with SpamAssassin Rule Actions and a bit 
>> of lateral thinking :-)
>> Jules.
>> On 13/1/09 17:58, Michael Masse wrote:
>>> Is there any way MailScanner can blacklist email that says it's from 
>>> mydomain, but comes from an IP outside of my ipspace?   We force all 
>>> of our clients to use our specific smtp server.
>>> We've been getting hit very hard with these self addressed spams 
>>> latelyand MailScanner has been doing a fantastic job of tagging 
>>> these as spam,but the problem is that even though our commercial 
>>> email system accepts spamassassin header tags to put them in the 
>>> appropriate junk folder automatically, it ignores the headers if it 
>>> thinks the sender is oneself and then I get complaints about these 
>>> spams getting through.
>>> The real solution is obviously for the commercial vendor to fix this 
>>> problem and trust spamassassin all the time, but this has been going 
>>> on foryears and they aren't going to change it any time soon, so I'm 
>>> stuck with getting rid of these messages at the SMTP/Mailscanner 
>>> stage before theyget passed on to the rest of the mail system.    
>>> I've implemented mailfromd which allows me to automatically reject 
>>> any email that uses our domain as a sending domain and doesn't come 
>>> from within our ip space at the SMTP negotiation envelope level and 
>>> this is blocking 99% of them, but thereare a few that are still 
>>> sneaking through because they use some other domain at the smtp 
>>> "mail from:" envelope stage which allows them to bypass mailfromd, 
>>> but then in the data portion of the email they use our domain in 
>>> the  from: address in the header which then confuses our email 
>>> system into ignoring the spamassassin header tag again.
>>> As I said, MailScanner/Spamassassin is properly tagging these emails 
>>> asspam, but the tags get ignored by an oversight on our mail 
>>> system.  We force all of our clients to use our own smtp server, so 
>>> there should neverbe a case of an email with a sender address of our 
>>> domain coming from outside of our domain.    Is it possible for 
>>> MailScanner to blacklist these?
>>> -Mike
>> Jules
>> Jules
> Julian,
> What would happen if someone sent an email with a From: from my domain 
> using their home ISP smtp server?  Would that be blocked by your example?
Yes. But that was what the original request wanted to do, at least as I 
read it. The same block would happen if you published an SPF record 
saying that mail from could only come from 152.78.71 (in my 

This is why I publish an SPF record that says "anything goes" for my own 
domain at work. SPF doesn't help me at all, for mail coming from my domain.


Julian Field MEng CITP CEng
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MailScanner customisation, or any advanced system administration help?
Contact me at Jules at Jules.FM

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