blacklisting local domain?
Julian Field
MailScanner at ecs.soton.ac.uk
Tue Jan 13 19:15:32 GMT 2009
On 13/1/09 18:18, Alex Neuman van der Hans wrote:
> It is, but it's better to do at the MTA stage with SPF and mta rules
> than it is to do it at mailscanner.
>
> Otherwise you'd have to do something like:
>
> From: *@yourdomain.com and From: 1.2.3.4 no
> From: *@yourdomain.com and From: 2.3.4.5 no
> From: *@yourdomain.com and From: 127.0.0.1 no
> From: *@yourdomain.com yes
>
> in your spam.blacklists.rules file. I guess.
That won't work as it will check the envelope sender, he wanted to check
the From: header.
Nice try though :-)
Jules.
>
>
> On Jan 13, 2009, at 12:58 PM, Michael Masse wrote:
>
>> Is there any way MailScanner can blacklist email that says it's from
>> my domain, 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
>> lately and 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 for years 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 they get 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 there are 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
>> as spam, 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 never be 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
>>
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>
Jules
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Julian Field MEng CITP CEng
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