Postfix: filter sender address base specific ipaddress

Admin pengelola mailserver, tentu tahu dengan yang bernama SPAM.

Dengan tools spamassassin atau policyd tentu akan bisa mengurangi spam dari luar network.

Yang jadi masalah, bagaimana bila spamnya berasal dari dalam network ?

Bisa bisa mabok mailservernya menerima banyak spam dari internal network.
Setelah google sana sini, tanya sana-sini, dimarahi pula sama pak asfik, tapi diberi clue mujarab.

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Instalasi Maia Mailguard di Ubuntu 8.04 Server

Tulisan asli dokumen ini mempergunakan ubuntu 6.06 dibuat oleh bang cecep dapat di lihat di situs ini
Instalasi Maia Mailguard di Ubuntu 6.06 Server (LTS)

Untuk versi 8.04 ada sedikit perbedaan di php dan smarty.
Juga saya tambahkan beberapa clue agar maia dapat langsung berjalan, tanpa harus trouble-shot lagi.

Pastikan postfix sudah terinstall dan berfungsi dengan baik dan benar.
Edit file master.cf pada postfix untuk menerima request dari port 10025.

vi /etc/postfix/master.cf
127.0.0.1:10025 inet n  -       n     -       -  smtpd
-o content_filter=
-o local_recipient_maps=
-o relay_recipient_maps=
-o smtpd_restriction_classes=
-o smtpd_client_restrictions=
-o smtpd_helo_restrictions=
-o smtpd_sender_restrictions=
-o smtpd_recipient_restrictions=permit_mynetworks,reject
-o mynetworks=127.0.0.0/8
-o strict_rfc821_envelopes=yes
/etc/init.d/postfix restart

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Memperkaya Rules SpamAssassin

Judul asli dan tulisan aslinya, saya dapat di situs bung dicky.

Entah mengapa setiap kali di kopi paste ke konsol putty selalu error.
Ternyata ada subtitusi simbol dari halaman web bung dicky ke konsol putty.
Dari tanda “-” menjadi “.” dan beberapa tanda “-” seharusnya “- -”

Supaya tidak salah kopi paste lagi, saya tulis ulang di web ini.
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Baca Flooding junk di smtp via mrtg

Pas lagi login ke smtp, dan mailq, kaget … ada 13ribu queue yang masih nunggu di panggil.
Inget kejadian waktu diflooding sama sandang. ada 100-an ribu email yang bikin postfix megap-megap.

Sebetulnya bila mau awas, hal ini bisa dideteksi dini.
Dengan bantuan grafik mrtg dapat dibaca bila smtp menerima kiriman sampah bertubi-tubi.
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How to stop (smtp) viruses !!

Diambil dari http://forum.mikrotik.com/viewtopic.php?t=11474

Hi, i created these 2 simple rules for firewall forward and this work very fine…… do not say it to anybody ;) :D

2 ;;; BLOCK SPAMMERS OR INFECTED USERS
chain=forward protocol=tcp dst-port=25 \
src-address-list=spammer action=drop

3 ;;; Detect and add-list SMTP virus or spammers
chain=forward protocol=tcp dst-port=25 connection-limit=30,32 \
limit=50,5 src-address-list=!spammer action=add-src-to-address-list \
address-list=spammer address-list-timeout=1d

When detect an infected user with a worm or doing spamming this rule add this user to a spammer list and block the SMTP outgoing for 1 day ;)

Regards!
Alessio

How to convert a MT box in an Anti Spam server with v2.9

Diambil dari http://forum.mikrotik.com/viewtopic.php?t=15721

Hi there, for months I have the idea how to transform one Mikrotik OS in an Anti Spam server. After more than 20 days applying few scripts, firewall rules and address list, I have achieved reduce from 45.000 mails per day to only 11.000/12.000 without many complaints from my customers.

Before continuing, some details about this:

Yes, I know that exists others solutions.
Yes, I know with Linux can obtain the same results.
Yes, I know that it seems a crazy solution.
Yes, I know (in the practice) that this solutions generate a moderate cpu usage. I have a Pentium IV with 75% of cpu usage (this can change with new features from MT… see scripts explanation) and we are a little ISP.
Yes, yes, yes…
but
I use MT from six years ago (when John Tully & Arnis Riekstins answered the company mails themselves) and always I try to resolve any networking necessity whit MT.
I had the trust that can resolve this whit MT.
and after thinking about this, I can’t never sleep all night from many days, so, for my health and wife I made it !!!

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