Categoria: Rete

Shorewall installazione e configurazione



 

Shorewall (Shoreline Firewall) è un firewall che si appoggia al sistema  Netfilter (iptables/ipchains) del kernel Linux, per una più semplice gestione di avanzate configurazioni di rete. Prima di iniziare nell'installazione di shorewall, bisogna prima disinstallare eventualmente l'altro firewall. Esempio: firestarter:

# apt-get remove --purge firestarter

# apt-get install shorewall shorewall-common shorewall-shell shorewall-doc dash

 

1) Partiamo con la configurazione del file interfaces:

# gedit /etc/shorewall/interfaces

all'interno copiamo questo:

# Shorewall version 3.0 – Sample Interfaces File for one-interface configuration.
#
# /etc/shorewall/interfaces
#
# You must add an entry in this file for each network interface on your
# firewall system.
#
# Columns are:
#
# ZONE Zone for this interface. Must match the name of a
# zone defined in /etc/shorewall/zones. You may not
# list the firewall zone in this column.
#
# If the interface serves multiple zones that will be
# defined in the /etc/shorewall/hosts file, you should
# place "-" in this column.
#
# If there are multiple interfaces to the same zone,
# you must list them in separate entries:
#
# Example:
#
# loc eth1 –
# loc eth2 –
#
# INTERFACE Name of interface. Each interface may be listed only
# once in this file. You may NOT specify the name of
# an alias (e.g., eth0:0) here; see
# https://www.shorewall.net/FAQ.htm#faq18
#
# You may specify wildcards here. For example, if you
# want to make an entry that applies to all PPP
# interfaces, use 'ppp+'.
#
# There is no need to define the loopback interface (lo)
# in this file.
#
# BROADCAST The broadcast address for the subnetwork to which the
# interface belongs. For P-T-P interfaces, this
# column is left blank.If the interface has multiple
# addresses on multiple subnets then list the broadcast
# addresses as a comma-separated list.
#
# If you use the special value "detect", the firewall
# will detect the broadcast address for you. If you
# select this option, the interface must be up before
# the firewall is started, you must have iproute
# installed.
#
# If you don't want to give a value for this column but
# you want to enter a value in the OPTIONS column, enter
# "-" in this column.
#
# OPTIONS A comma-separated list of options including the
# following:
#
# dhcp – Specify this option when any of
# the following are true:
# 1. the interface gets its IP address
# via DHCP
# 2. the interface is used by
# a DHCP server running on the firewall
# 3. you have a static IP but are on a LAN
# segment with lots of Laptop DHCP
# clients.
# 4. the interface is a bridge with
# a DHCP server on one port and DHCP
# clients on another port.
#
# norfc1918 – This interface should not receive
# any packets whose source is in one
# of the ranges reserved by RFC 1918
# (i.e., private or "non-routable"
# addresses. If packet mangling or
# connection-tracking match is enabled in
# your kernel, packets whose destination
# addresses are reserved by RFC 1918 are
# also rejected.
#
# routefilter – turn on kernel route filtering for this
# interface (anti-spoofing measure). This
# option can also be enabled globally in
# the /etc/shorewall/shorewall.conf file.
#
# logmartians – turn on kernel martian logging (logging
# of packets with impossible source
# addresses. It is suggested that if you
# set routefilter on an interface that
# you also set logmartians. This option
# may also be enabled globally in the
# /etc/shorewall/shorewall.conf file.
#
# blacklist – Check packets arriving on this interface
# against the /etc/shorewall/blacklist
# file.
#
# maclist – Connection requests from this interface
# are compared against the contents of
# /etc/shorewall/maclist. If this option
# is specified, the interface must be
# an ethernet NIC and must be up before
# Shorewall is started.
#
# tcpflags – Packets arriving on this interface are
# checked for certain illegal combinations
# of TCP flags. Packets found to have
# such a combination of flags are handled
# according to the setting of
# TCP_FLAGS_DISPOSITION after having been
# logged according to the setting of
# TCP_FLAGS_LOG_LEVEL.
#
# proxyarp –
# Sets
# /proc/sys/net/ipv4/conf/<interface>/proxy_arp.
# Do NOT use this option if you are
# employing Proxy ARP through entries in
# /etc/shorewall/proxyarp. This option is
# intended soley for use with Proxy ARP
# sub-networking as described at:
#
#
# routeback – If specified, indicates that Shorewall
# should include rules that allow
# filtering traffic arriving on this
# interface back out that same interface.
#
# arp_filter – If specified, this interface will only
# respond to ARP who-has requests for IP
# addresses configured on the interface.
# If not specified, the interface can
# respond to ARP who-has requests for
# IP addresses on any of the firewall's
# interface. The interface must be up
# when Shorewall is started.
#
# arp_ignore[=<number>]
# – If specified, this interface will
# respond to arp requests based on the
# value of <number>.
#
# 1 – reply only if the target IP address
# is local address configured on the
# incoming interface
#
# 2 – reply only if the target IP address
# is local address configured on the
# incoming interface and both with the
# sender's IP address are part from same
# subnet on this interface
#
# 3 – do not reply for local addresses
# configured with scope host, only
# resolutions for global and link
# addresses are replied
#
# 4-7 – reserved
#
# 8 – do not reply for all local
# addresses
#
# If no <number> is given then the value
# 1 is assumed
#
# WARNING — DO NOT SPECIFY arp_ignore
# FOR ANY INTERFACE INVOLVED IN PROXY ARP.
#
# nosmurfs – Filter packets for smurfs
# (packets with a broadcast
# address as the source).
#
# Smurfs will be optionally logged based
# on the setting of SMURF_LOG_LEVEL in
# shorewall.conf. After logging, the
# packets are dropped.
#
# detectnets – Automatically taylors the zone named
# in the ZONE column to include only those
# hosts routed through the interface.
#
# upnp – Incoming requests from this interface
# may be remapped via UPNP (upnpd).
#
# WARNING: DO NOT SET THE detectnets OPTION ON YOUR
# INTERNET INTERFACE.
#
# The order in which you list the options is not
# significant but the list should have no embedded white
# space.
#
# Example 1: Suppose you have eth0 connected to a DSL modem and
# eth1 connected to your local network and that your
# local subnet is 192.168.1.0/24. The interface gets
# it's IP address via DHCP from subnet
# 206.191.149.192/27. You have a DMZ with subnet
# 192.168.2.0/24 using eth2.
#
# Your entries for this setup would look like:
#
# net eth0 206.191.149.223 dhcp
# local eth1 192.168.1.255
# dmz eth2 192.168.2.255
#
# Example 2: The same configuration without specifying broadcast
# addresses is:
#
# net eth0 detect dhcp
# loc eth1 detect
# dmz eth2 detect
#
# Example 3: You have a simple dial-in system with no ethernet
# connections.
#
# net ppp0 –
#
# For additional information, see
#
#
###############################################################################
#ZONE INTERFACE BROADCAST OPTIONS
net eth0   detect      routefilter,dhcp,tcpflags,logmartians,nosmurfs
#LAST LINE — ADD YOUR ENTRIES BEFORE THIS ONE — DO NOT REMOVE

 

Attenzione:Se al posto del router abbiamo un modem cambiare eth0 con ppp0. In ogni caso cercare di adattarlo alle nostre esigenze e configurazione.

 

2) Configurazione del file policy:

# gedit /etc/shorewall/policy

all'interno copiamo questo:

# Shorewall version 3.0 – Sample Policy File for one-interface configuration.
#
# /etc/shorewall/policy
#
# THE ORDER OF ENTRIES IN THIS FILE IS IMPORTANT
#
# This file determines what to do with a new connection request if we
# don't get a match from the /etc/shorewall/rules file . For each
# source/destination pair, the file is processed in order until a
# match is found ("all" will match any client or server).
#
# INTRA-ZONE POLICIES ARE PRE-DEFINED
#
# For $FW and for all of the zoned defined in /etc/shorewall/zones,
# the POLICY for connections from the zone to itself is ACCEPT (with no
# logging or TCP connection rate limiting but may be overridden by an
# entry in this file. The overriding entry must be explicit (cannot use
# "all" in the SOURCE or DEST).
#
# Columns are:
#
# SOURCE Source zone. Must be the name of a zone defined
# in /etc/shorewall/zones, $FW or "all".
#
# DEST Destination zone. Must be the name of a zone defined
# in /etc/shorewall/zones, $FW or "all"
#
# POLICY Policy if no match from the rules file is found. Must
# be "ACCEPT", "DROP", "REJECT", "CONTINUE" or "NONE".
#
# ACCEPT – Accept the connection
# DROP – Ignore the connection request
# REJECT – For TCP, send RST. For all other,
# send "port unreachable" ICMP.
# QUEUE – Send the request to a user-space
# application using the QUEUE target.
# CONTINUE – Pass the connection request past
# any other rules that it might also
# match (where the source or
# destination zone in those rules is
# a superset of the SOURCE or DEST
# in this policy).
# NONE – Assume that there will never be any
# packets from this SOURCE
# to this DEST. Shorewall will not set
# up any infrastructure to handle such
# packets and you may not have any
# rules with this SOURCE and DEST in
# the /etc/shorewall/rules file. If
# such a packet _is_ received, the
# result is undefined. NONE may not be
# used if the SOURCE or DEST columns
# contain the firewall zone ($FW) or
# "all".
#
# If this column contains ACCEPT, DROP or REJECT and a
# corresponding common action is defined in
# /etc/shorewall/actions (or
# /usr/share/shorewall/actions.std) then that action
# will be invoked before the policy named in this column
# is enforced.
#
# LOG LEVEL If supplied, each connection handled under the default
# POLICY is logged at that level. If not supplied, no
# log message is generated. See syslog.conf(5) for a
# description of log levels.
#
# Beginning with Shorewall version 1.3.12, you may
# also specify ULOG (must be in upper case). This will
# log to the ULOG target and sent to a separate log
# through use of ulogd
# ).
#
# If you don't want to log but need to specify the
# following column, place "-" here.
#
# LIMIT:BURST If passed, specifies the maximum TCP connection rate
# and the size of an acceptable burst. If not specified,
# TCP connections are not limited.
#
# See for additional information.
#
###############################################################################
#SOURCE DEST POLICY LOG LEVEL LIMIT:BURST
$FW net ACCEPT
net all DROP info
# The FOLLOWING POLICY MUST BE LAST
all all REJECT info
#LAST LINE — ADD YOUR ENTRIES ABOVE THIS LINE — DO NOT REMOVE

 

 

3) Creazione del file di configurazione zones:

# gedit /etc/shorewall/zones

all'interno copiamo questo:

# Shorewall version 3.0 – Sample Zones File for one-interface configuration.
#
# /etc/shorewall/zones
#
# This file determines your network zones.
#
# Columns are:
#
# ZONE Short name of the zone (5 Characters or less in length).
# The names "all" and "none" are reserved and may not be
# used as zone names.
#
# Where a zone is nested in one or more other zones,
# you may follow the (sub)zone name by ":" and a
# comma-separated list of the parent zones. The parent
# zones must have been defined in earlier records in this
# file.
#
# Example:
#
# #ZONE TYPE OPTIONS
# a ipv4
# b ipv4
# c:a,b ipv4
#
# Currently, Shorewall uses this information only to reorder the
# zone list so that parent zones appear after their subzones in
# the list. In the future, Shorewall may make more extensive use
# of that information.
#
# TYPE ipv4 – This is the standard Shorewall zone type and is the
# default if you leave this column empty or if you enter
# "-" in the column. Communication with some zone hosts
# may be encrypted. Encrypted hosts are designated using
# the 'ipsec'option in /etc/shorewall/hosts.
# ipsec – Communication with all zone hosts is encrypted
# Your kernel and iptables must include policy
# match support.
# firewall
# – Designates the firewall itself. You must have
# exactly one 'firewall' zone. No options are
# permitted with a 'firewall' zone. The name that you
# enter in the ZONE column will be stored in the shell
# variable $FW which you may use in other configuration
# files to designate the firewall zone.
#
# OPTIONS, A comma-separated list of options as follows:
# IN OPTIONS,
# OUT OPTIONS reqid=<number> where <number> is specified
# using setkey(8) using the 'unique:<number>
# option for the SPD level.
#
# spi=<number> where <number> is the SPI of
# the SA used to encrypt/decrypt packets.
#
# proto=ah|esp|ipcomp
#
# mss=<number> (sets the MSS field in TCP packets)
#
# mode=transport|tunnel
#
# tunnel-src=<address>[/<mask>] (only
# available with mode=tunnel)
#
# tunnel-dst=<address>[/<mask>] (only
# available with mode=tunnel)
#
# strict Means that packets must match all rules.
#
# next Separates rules; can only be used with
# strict..
#
# Example:
# mode=transport,reqid=44
#
# The options in the OPTIONS column are applied to both incoming
# and outgoing traffic. The IN OPTIONS are applied to incoming
# traffic (in addition to OPTIONS) and the OUT OPTIONS are
# applied to outgoing traffic.
#
# If you wish to leave a column empty but need to make an entry
# in a following column, use "-".
#
# THE ORDER OF THE ENTRIES IN THIS FILE IS IMPORTANT IF YOU HAVE NESTED OR
# OVERLAPPING ZONES DEFINED THROUGH /etc/shorewall/hosts.
#
# See
###############################################################################
#ZONE TYPE OPTIONS IN OUT
# OPTIONS OPTIONS
fw firewall
net ipv4
#LAST LINE – ADD YOUR ENTRIES ABOVE THIS ONE – DO NOT REMOVE

 

 

4) Configurazione del file rules.

# gedit /etc/shorewall/rules

all'interno copiamo questo:

Leggi tutto “Shorewall installazione e configurazione”

Linux e chiavetta Internet ONDA MT503HS 7.2 MEGA

Questa sera ho avuto una piacevole sorpresa direttamente dal sito TIm, dove sono entrato a  controllare quanti punti avevo accumulato con MilleunaTim. I miei punti sono circa 4500 e sono andato a controllare se c’era un premio che potesse interessarmi. Tra tutti i premi mi soffermo sulla chiavetta Internet ONDA MT503HS 7.2 MEGA, dato che oggi la mobilità è importante per uno che smanetta (avendo tempo) e dato che il portatile è fermo a prendere polvere, mi dedico alla lettura dell’eventuale abbonamento e delle caratteristiche tecniche, ed è con stupore che leggo un qualcosa che chissà quante volte avrei voluto leggere in questi anni, quando cristonavo notti intere per fare andare decentemente le cose. Sara forse il segno che le cose stanno cambiando? …Mah….non ci credo poi molto.

Caratteristiche principali:

USB PenDrive Multimode GPRS/EDGE/UMTS/HSPDA
HSPDA 2100 MHz – fino a 7.2 Mbps in ricezione
UMTS 2100 MHz – fino a 384 Kbps
TriBand GPRS/EDGE 900/1800/1900 fino a 200 Kbps
Dimensioni: 88x28x14 mm.
Peso: 30 grammi
Software per Windows autoinstallante
Supporto driver NDIS
Antenna integrata
Invio e ricezione SMS
Gestione rubrica SIM
Slot per schede MicroSD (fino a 2GB)

Requisiti di sistema:

Windows 2000 / XP Home / XP Professional / XP Tablet PC / XP Professional x64 / VISTA (32/64 bit)
Mac OS 10.3.x, 10.4.x,10.5.1
Linux Debian, Fedora
RAM 128MB
Spazio libero su Hard Disk: 20MB
Risoluzione display: 800×600 pixel o sup. (si consiglia 1024×768)
Lettore CD-ROM

Contenuto Package:

MT5032HS
Cavo USB
CD-ROM installazione Mac OS e Linux
Guida rapida d’utente
.

Amministrare la banda con Trickle

 

Trickle si incarica di limitare l’uso della banda sia in download che in upload di una applicazione specifica.

Questo può essere molto utile se nel contempo si volesse continuare a navigare senza avere la banda satura.

Si puo usare con programmi tipo: Deluge, Amule, apt-get upgrade ecc ecc. Trickle è presente nei repository Debian.

Esempio:

trickle -u 5 -d 12 apt-get upgrade

In questo caso si incarica di limitate apt-get upgrade in upload a 5 kbps  ed in download a 12 kbps,

oppure:

trickle -d 50 deluge

Deluge utilizzerà solo 50kbps. Per altre opzioni consultare il man.

 

Netspeed applet per Gnome

 

 

 

Netspeed è un applet per Gnome utilissimo per controllare la velocità di banda.  Molto utile quando si usano programmi p2p

per poter verificare la velocità di download. Ha bisogno di poche configurazioni ed è presente nei repository. Una volta

installato basta aggiungerlo al pannello, si trova sotto la voce Network Monitor.

Script per Gmail

 

Per scaricare la posta da Gmail io uso uno script per me utilissimo, dato che non sono interessato ad usare client di posta, ma al massimo i plugins per iceweasel-firefox. La particolarità di questo script è che una volta controllato il numero di nuove mail ricevute, si accende il led num lock (oppure caps lock o skroll lock) e lampeggia tante volte, quanto sono le email ricevute. L’unica dipendenza che serve è blinkd, presente nei repository.

apt-get install blinkd

Questo lo script:

#!/bin/bash
cd /tmp
username=Vostro_Username_Google_Senza_@gmail.com
password=$( zenity --entry --title="Password Gmail" --text="Inserisci password :" --hide-text )
if [[ -z $password ]]
then exit
fi
if [[ $password == "0" ]]
then password=$( zenity --entry --title="Password Gmail" --text="Inserisci password :" )
fi
sleep 15
function get_rss
{
wget -q -O .gmail_rss https://$username:$password@mail.google.com/mail/feed/atom --no-check-certificate
fc=$( cat .gmail_rss | grep "fullcount" | grep -o [1-9] )
}
while true
do
get_rss
if ! [[ fc == "0" ]]
then
    until [[ $fc == "" ]]
    do
    blink -n -r $fc
    get_rss
    sleep 15
    done
blink
fi
sleep 5m
done
rm -f .gmail_rss

chmod +x nome_script

 

Naturalmente per visualizzare il file .gmail_rss in /tmp bisogna visualizzare i file nascosti.

Lo script verifica la presenza di nuove mails ogni 10 minuti, per cambiare basta modificare "sleep 10m"

Il led che lampeggia è il num lock, per modificarlo basta sostituire blink -n -r $fc con blink -c -r $fc e si passa al capslock.

Queste le altre opzioni:

  -c,   –capslockled   use Caps-Lock LED
  -h,   –help          display this help and exit
  -m s, –machine=s     let keyboard of machine s blink
  -n,   –numlockled    use Num-Lock LED
  -r n, –rate=n        set blink rate to n
  -s,   –scrolllockled use Scroll-Lock LED
  -t n, –tcp-port=n    use tcp port n
  -v,   –version       output version information and exit

Per fermare o far partire i demoni  /etc/init.d/blinkd stop-start-restart.

Per altro man blinkd.

 

Cambiare MAC address con Linux

 

Per cambiare il nostro MAC address non bisogna fare altro che eseguire 3 semplici passaggi.

Per prima cosa bisogna ricordarsi che i numeri e le lettere ammessi sono: 1 2 3 4 5 6 7 8 9 0 a b c d e f

Dopodiche ci si costruisce a piacere un MAC address tipo questo 1a:2b:3c:4d:5e:6f

Quindi da root

ifconfig eth0 down
ifconfig eth0 hw ether 1a:2b:3c:4d:5e:6f
ifconfig etho up

Per controllare il nuovo MAC address

ifconfig

 

Statistiche di sistema con Saidar

Saidar è un tool che serve per monitorare il sistema. Viene monitorato l’uso della cpu, della memoria, dei processi, della scheda di rete, e dei dischi. Funziona su diverse piattaforme, come, Solaris 2.x, Linux 2.2/2.4/2.6, FreeBSD 4.x/5.x, NetBSD 1.6.x, OpenBSD 3.x, DragonFly BSD 1.0, HP-UX, e Cygwin. Su distribuzioni Debian-based lo s’installa con:

 

sudo apt-get install saidar

e lo si lancia da terminale con

 

saidar

 

Per altre opzioni vedere qua