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 !!!

Read more »

Disconnecting the users with bad signal [2.9.X]

Diambil dari http://forum.mikrotik.com/viewtopic.php?f=9&t=20370

YOU WANT IT – YOU GOT IT

Small manual:
Install – click system->scripts, click “+”, enter in the name whatevery you want (like signallimiter), click ok, done!

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How to prevent NATed access

Sesuai dengan judul diatas,
inti dari kasus ini adalah penyedia jasa tidak ingin BW yang diberikan kepada user di sharing lagi mempergunakan nat-router.

Ilmu baru buat saya, dengan memberikan TTL=1 ?, mmmm aneh sekali.
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How to limit a user to a given amount of traffic?

Diambil dari http://forum.mikrotik.com/viewtopic.php?f=9&t=20420

:local sum; :local traf;
:set sum 0
/ip firewall rule forward {
:foreach i in [find] do={:incr sum}
:for i from=1 to=$sum  do={
:set traf [get [find comment=("user" . $i)]
bytes]
:set traf ($traf/1073741824)
:if ($traf>1) do={:log facility=System-Info \
message=("user" . $i ." exceeded 1Gb limit!")}
}
}

A script to watch the battery voltage?

Script dibawah berfungsi untuk memberitahu admin via email, bila ada masalah listrik pada UPS yang dipakai oleh mikrotik.
Fungsi dibawah belum pernah saya coba, tapi ide-nya menarik untuk dipelajari.

dari http://forum.mikrotik.com/viewtopic.php?f=9&t=1605

:set sysname [/system identity get name]

:set datetime ([/system clock get date] . " " . [/system clock get time])# Erster Lauf und Flags noch uninitialisiert?

:if (("-" . $flagonbatt)="-") do {:global flagonbatt 0}

:if (("-" . $flagbatlow)="-") do {:global flagbatlow 0}

:set curonbatt false

:set curbatlow false

/system ups monitor [/system ups find name "ups1"] once do {:set curonbatt $on-battery; :set curbatlow $low-battery}

:if (($curonbatt) && ($flagonbatt=0)) do {

:global flagonbatt 1

/tool e-mail send from="ups" to="somwwhere" server="1.1.1.1" subject=($sysname . " ist ohne Strom!") body=($sysname . " hat keinen Saft seit " . $datetime)

:log info "Power-Fail: Email gesendet"

}

:if ((!$curonbatt) && ($flagonbatt=1)) do {

:global flagonbatt 0

/tool e-mail send from="ups" to="somewhere" server="1.1.1.1" subject=($sysname . " hat wieder Strom") body=($sysname . " saftelt wieder seit " . $datetime)

:log info "Power-Restore: Email gesendet"

}

:if (($curbatlow) && ($flagbatlow=0)) do {

:global flagbatlow 1

/tool e-mail send from="ups" to="somewhere" server="1.1.1.1" subject=($sysname . " Batterie leer!") body=($sysname . " hat fast keine Batterie mehr - " . $datetime)

:log info "Batt-Low: Email gesendet"

}

:if ((!$curbatlow) && ($flagbatlow=1)) do {

:global flagbatlow 0

/tool e-mail send from="ups" to="somwhere" server="1.1.1.1" subject=($sysname . " Batterie nachgeladen") body=($sysname . " Battery-Low beendet - " . $datetime)

:log info "Batt-Low-Ende: Email gesendet"

}