block spoofing mail

[ListAcc]

Martin,

There is a previous post about this.  Have you considered using SPF? One 
thing to cut down on spoofed mail is setup an ACL on the outside 
interface of your mail server that blocks all IP address not yet 
assigned or known for spam.  If you are using postfix as your MTA you 
can setup this up with smtpd restrictions. The below will help mitigate 
but I would suggest also putting up an ACL if you can to block your 
domain name from entering your outside interface if it's within your 
mail routing policy and setup.  Also scan all user computers for bots 
and etc that may be around. Make sure users must authenticate before 
sending....

For example:

in /etc/postfix/main.cf

smtpd_recipient_restrictions =
*    check_sender_mx_access cidr:/etc/postfix/bogus_mx *(see postfix for 
complete command usage and available restrictions)**
    permit

make sure you create the bogus_mx and place all the bad networks such as

in /etc/postfix/bogus_mx

0.0.0.0/8 550 Bad Network
10.0.0.0/8 550 Bad Network
127.0.0.0/8 550 Bad Network

For a complete up to date list of bogons networks see 
http://www.team-cymru.org


Regards,
Otis


Martin Hepworth wrote:
> 2009/1/10 ichwan nur hakim <chokimbo at gmail.com>:
>   
>> hi guys,
>>
>> how block spoofing mail with mailscanner..?? coz my office mail very much
>> recipient spoofing mail.
>> Thank's
>>
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>>     
>
>
> HI
>
> perhaps you can give an example of what you mean by 'spoofing email'?
>
>