Re: Postfix trouble

[Adrian Minta <adrian.minta@gmail.com>]

Thank you all for suggestions !
I use antivirus and  antispam but in case of spam bots on my clients 
machines all those are ineffective :(
The simples solution I could find is to use SMTP auth, unfortunately 
will not be so easy to inform all clients about the change and to 
instruct them to change settings.


Theodore Knab wrote:

> You might want to ask the postfix mailing list. Your 
> configuration can be modified to block certain clients but it is a lot
> of work seeing they will always be changing.
>
> Here are some of the smtpd_restrictions I use on this box.
>
> smtpd_recipient_restrictions = 
>
> ####################################
> #used to stop virus infected machines on our net
> ####################################
>    reject_invalid_hostname,
>    reject_non_fqdn_sender,
>    reject_non_fqdn_recipient,
>    reject_unknown_sender_domain,
>    reject_unauth_pipelining,
>    check_client_access hash:/etc/postfix/badclients,
>    check_sender_access hash:/etc/postfix/broken_sender_exception,
>    permit_mynetworks,
>    reject_unknown_recipient_domain,
>    check_client_access hash:/etc/postfix/broken_sender_exception,
>    reject_unauth_destination,
>    #postgrey
>    check_policy_service inet:127.0.0.1:60000,
>    reject_non_fqdn_hostname,
>    reject_non_fqdn_sender,
>    #reject_unknown_client,
>    #eject unknown dns --> mailfrom: 
>    reject_unknown_sender_domain,
>    #reject unknown --> rcpt to:
>    #bad helo
>    #reverse lookup of ip sending 
>    #version 2 postfix only
>    reject_unverified_sender,
>    reject_multi_recipient_bounce,
>    reject_rbl_client sbl.spamhaus.org,
>    reject_rbl_client relays.ordb.org,
>    reject_rbl_client opm.blitzed.org,
>    reject_rbl_client blackholes.wirehub.net,
>    reject_rbl_client dynablock.wirehub.net,
>    reject_rbl_client proxies.relays.monkeys.org,
>    reject_rbl_client dnsbl.njabl.org,
>    #reject_rbl_client list.dsbl.org,
>    #reject_rbl_client cbl.abuseat.org,
>
>    #if they get here they are allowd
>    permit
> :
>
>
> It is easier just to use global spam reduction techniques.
>
> Here are some simple ways to reduce spam postfix:
> Use RBHL with Postfix.
> Use Postgrey
>
> Clamd with Amavis will help reduce viruses but it might take a little 
> time to figure out how to get Amavis working. 
>
> Amavis is setup in my master.cf not the main.cf.
>
> Spam-assassin is good but it takes more time than the above
> to setup. 
>
> On 16/09/05 19:22 +0300, Adrian Minta wrote:
>  
>
> > I need an advice on the following problem:
> > I setup an email server for a small ISP. The server is sarge with 
> > postfix as MTA. Unfortunately some of the clients contacted a 
> > virus/spambot that is sending spam via my mail server. I want to bloc 
> > spam that came from $mynetworks but the sender in not in $relay_domains. 
> > Is such thing possible ?
> >
> > Thank you in advance !
> >
> > --
> > Best regards,
> > Adrian Minta
> >
> >
> > --
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> >
> >    
>
>  


--
Best regards,
Adrian Minta