Re: redireccionar ssh a la lan
On Wed, Feb 02, 2005 at 10:02:59AM -0300, velkrox@yahoo.com.ar wrote:
> Date: Wed, 2 Feb 2005 10:02:59 -0300
> From: velkrox@yahoo.com.ar
> Subject: Re: redireccionar ssh a la lan
> To: debian-user-spanish@lists.debian.org
> X-Mailer: Microsoft Outlook Express 6.00.2800.1478
>
> walter:
> depende de varias cosas, por ej: que el chain forward tenga la default
> policy drop, y no lo estes aceptando. seria bueno que postees las reglas
> (completo, que no falte nada) como para poder ayudarte.
>
> igualmente, te comento que en mi casa forwardeo con iptables a una de las
> pcs de adentro de la lan, y no tengo ningun problema.
es un choclo ... no me maten
#!/bin/sh
# This is the location of the iptables command
IPTABLES="/sbin/iptables"
case "$1" in
stop)
echo "Shutting down firewall..."
$IPTABLES -F
$IPTABLES -F -t mangle
$IPTABLES -F -t nat
$IPTABLES -X
$IPTABLES -X -t mangle
$IPTABLES -X -t nat
$IPTABLES -P INPUT ACCEPT
$IPTABLES -P OUTPUT ACCEPT
$IPTABLES -P FORWARD ACCEPT
echo "...done"
;;
status)
echo $"Table: filter"
iptables --list
echo $"Table: nat"
iptables -t nat --list
echo $"Table: mangle"
iptables -t mangle --list
;;
restart|reload)
$0 stop
$0 start
;;
start)
echo "Starting Firewall..."
echo ""
##--------------------------Begin Firewall---------------------------------##
#----Default-Interfaces-----#
## Default external interface (used, if EXTIF isn't specified on command line)
DEFAULT_EXTIF="eth0"
## Default internal interface (used, if INTIF isn't specified on command line)
DEFAULT_INTIF="eth1"
#----Special Variables-----#
# IP Mask for all IP addresses
UNIVERSE="0.0.0.0/0"
# Specification of the high unprivileged IP ports.
UNPRIVPORTS="1024:65535"
# Specification of X Window System (TCP) ports.
XWINPORTS="6000:6063"
#----Flood Variables-----#
# Overall Limit for TCP-SYN-Flood detection
TCPSYNLIMIT="5/s"
# Burst Limit for TCP-SYN-Flood detection
TCPSYNLIMITBURST="10"
# Overall Limit for Loggging in Logging-Chains
LOGLIMIT="2/s"
# Burst Limit for Logging in Logging-Chains
LOGLIMITBURST="10"
# Overall Limit for Ping-Flood-Detection
PINGLIMIT="5/s"
# Burst Limit for Ping-Flood-Detection
PINGLIMITBURST="10"
#----Automatically determine infos about involved interfaces-----#
### External Interface:
## Get external interface from command-line
## If no interface is specified then set $DEFAULT_EXTIF as EXTIF
if [ "x$2" != "x" ]; then
EXTIF=$2
else
EXTIF=$DEFAULT_EXTIF
fi
echo External Interface: $EXTIF
## Interfaz que conecta a internet, en este caso la eth0 conecta
## al modem ADSL - Determine external IP 200.40.171.158
EXTIP="`ifconfig $EXTIF | grep inet | cut -d : -f 2 | cut -d \ -f 1`"
if [ "$EXTIP" = '' ]; then
echo "Aborting: Unable to determine the IP-address of $EXTIF !"
exit 1
fi
echo External IP: $EXTIP
## Determine external gateway 200.40.171.157
EXTGW=`route -n | grep -A 4 UG | awk '{ print $2}'`
echo Default GW: $EXTGW
echo " --- "
### Internal Interface:
## Get internal interface from command-line
## If no interface is specified then set $DEFAULT_INTIF as INTIF
if [ "x$3" != "x" ]; then
INTIF=$3
else
INTIF=$DEFAULT_INTIF
fi
echo Internal Interface: $INTIF
## Interfaz que conecta con la LAN - Determine internal IP 192.168.1.9
INTIP="`ifconfig $INTIF | grep inet | cut -d : -f 2 | cut -d \ -f 1`"
if [ "$INTIP" = '' ]; then
echo "Aborting: Unable to determine the IP-address of $INTIF !"
exit 1
fi
echo Internal IP: $INTIP
## Determine internal netmask
INTMASK="`ifconfig $INTIF | grep Mask | cut -d : -f 4`"
echo Internal Netmask: $INTMASK
## Determine network address of the internal network
INTLAN=$INTIP'/'$INTMASK
echo Internal LAN: $INTLAN
echo ""
#----Load IPTABLES-modules-----#
#Insert modules- should be done automatically if needed
#If the IRC-modules are available, uncomment them below
echo "Loading IPTABLES modules"
dmesg -n 1
#Kill copyright display on module load
/sbin/modprobe ip_tables
/sbin/modprobe iptable_filter
#/sbin/modprobe ip_conntrack
/sbin/modprobe ip_conntrack_ftp
/sbin/modprobe ip_nat_ftp
#sbin/modprobe ip_conntrack_irc ports=$IRCPORTS
#sbin/modprobe ip_nat_irc ports=$IRCPORTS
dmesg -n 6
echo " --- "
#----Clear/Reset all chains-----#
#Clear all IPTABLES-chains
#Flush everything, start from scratch
$IPTABLES -F
$IPTABLES -F -t mangle
$IPTABLES -F -t nat
$IPTABLES -X
$IPTABLES -X -t mangle
$IPTABLES -X -t nat
#Set default policies to DROP
$IPTABLES -P INPUT DROP
$IPTABLES -P OUTPUT DROP
$IPTABLES -P FORWARD DROP
#----Set network sysctl options-----#
echo "Setting sysctl options"
#Enable forwarding in kernel - Aviso al kernel que acepte ip_forwarding
echo 1 > /proc/sys/net/ipv4/ip_forward
#Disabling IP Spoofing attacks.
echo 2 > /proc/sys/net/ipv4/conf/all/rp_filter
#Don't respond to broadcast pings (Smurf-Amplifier-Protection)
echo "1" > /proc/sys/net/ipv4/icmp_echo_ignore_broadcasts
#Block source routing
echo 0 > /proc/sys/net/ipv4/conf/all/accept_source_route
#Kill timestamps
echo 0 > /proc/sys/net/ipv4/tcp_timestamps
#Enable SYN Cookies
echo 1 > /proc/sys/net/ipv4/tcp_syncookies
#Kill redirects
echo 0 > /proc/sys/net/ipv4/conf/all/accept_redirects
#Enable bad error message protection
echo 1 > /proc/sys/net/ipv4/icmp_ignore_bogus_error_responses
#Log martians (packets with impossible addresses)
echo 1 > /proc/sys/net/ipv4/conf/all/log_martians
#Set out local port range
echo "32768 61000" > /proc/sys/net/ipv4/ip_local_port_range
#Reduce DoS'ing ability by reducing timeouts
echo 30 > /proc/sys/net/ipv4/tcp_fin_timeout
echo 2400 > /proc/sys/net/ipv4/tcp_keepalive_time
echo 0 > /proc/sys/net/ipv4/tcp_window_scaling
echo 0 > /proc/sys/net/ipv4/tcp_sack
echo " --- "
echo "Creating user-chains"
#----Create logging chains-----#
#Invalid packets (not ESTABLISHED,RELATED or NEW)
#Paquetes no validos (no establecidos, relacionados o nuevos)
$IPTABLES -N LINVALID
$IPTABLES -A LINVALID -m limit --limit $LOGLIMIT --limit-burst $LOGLIMITBURST -j LOG --log-level DEBUG --log-prefix "fp=INVALID:1 a=DROP "
$IPTABLES -A LINVALID -j DROP
#TCP-Packets with one ore more bad flags
#Paquetes TCP con una o mas bandera mala
$IPTABLES -N LBADFLAG
$IPTABLES -A LBADFLAG -m limit --limit $LOGLIMIT --limit-burst $LOGLIMITBURST -j LOG --log-level DEBUG --log-prefix "fp=BADFLAG:1 a=DROP "
$IPTABLES -A LBADFLAG -j DROP
#Logging of connection attempts on special ports (Trojan portscans, special services, etc.)
$IPTABLES -N LSPECIALPORT
$IPTABLES -A LSPECIALPORT -m limit --limit $LOGLIMIT --limit-burst $LOGLIMITBURST -j LOG --log-level DEBUG --log-prefix "fp=SPECIALPORT:1 a=DROP "
$IPTABLES -A LSPECIALPORT -j DROP
#Logging of possible TCP-SYN-Floods
$IPTABLES -N LSYNFLOOD
$IPTABLES -A LSYNFLOOD -m limit --limit $LOGLIMIT --limit-burst $LOGLIMITBURST -j LOG --log-level DEBUG --log-prefix "fp=SYNFLOOD:1 a=DROP "
$IPTABLES -A LSYNFLOOD -j DROP
#Logging of possible Ping-Floods
$IPTABLES -N LPINGFLOOD
$IPTABLES -A LPINGFLOOD -m limit --limit $LOGLIMIT --limit-burst $LOGLIMITBURST -j LOG --log-level DEBUG --log-prefix "fp=PINGFLOOD:1 a=DROP "
$IPTABLES -A LPINGFLOOD -j DROP
#All other dropped packets
$IPTABLES -N LDROP
$IPTABLES -A LDROP -p tcp -m limit --limit $LOGLIMIT --limit-burst $LOGLIMITBURST -j LOG --log-level DEBUG --log-prefix "fp=TCP:1 a=DROP "
$IPTABLES -A LDROP -p udp -m limit --limit $LOGLIMIT --limit-burst $LOGLIMITBURST -j LOG --log-level DEBUG --log-prefix "fp=UDP:2 a=DROP "
$IPTABLES -A LDROP -p icmp -m limit --limit $LOGLIMIT --limit-burst $LOGLIMITBURST -j LOG --log-level DEBUG --log-prefix "fp=ICMP:3 a=DROP "
$IPTABLES -A LDROP -f -m limit --limit $LOGLIMIT --limit-burst $LOGLIMITBURST -j LOG --log-level DEBUG --log-prefix "fp=FRAGMENT:4 a=DROP "
$IPTABLES -A LDROP -j DROP
#All other rejected packets
$IPTABLES -N LREJECT
$IPTABLES -A LREJECT -p tcp -m limit --limit $LOGLIMIT --limit-burst $LOGLIMITBURST -j LOG --log-level DEBUG --log-prefix "fp=TCP:1 a=REJECT "
$IPTABLES -A LREJECT -p udp -m limit --limit $LOGLIMIT --limit-burst $LOGLIMITBURST -j LOG --log-level DEBUG --log-prefix "fp=UDP:2 a=REJECT "
$IPTABLES -A LREJECT -p icmp -m limit --limit $LOGLIMIT --limit-burst $LOGLIMITBURST -j LOG --log-level DEBUG --log-prefix "fp=ICMP:3 a=REJECT "
$IPTABLES -A LREJECT -f -m limit --limit $LOGLIMIT --limit-burst $LOGLIMITBURST -j LOG --log-level DEBUG --log-prefix "fp=FRAGMENT:4 a=REJECT "
$IPTABLES -A LREJECT -p tcp -j REJECT --reject-with tcp-reset
$IPTABLES -A LREJECT -p udp -j REJECT --reject-with icmp-port-unreachable
$IPTABLES -A LREJECT -j REJECT
#----Create Accept-Chains-----#
#TCPACCEPT - Check for SYN-Floods before letting TCP-Packets in
$IPTABLES -N TCPACCEPT
$IPTABLES -A TCPACCEPT -p tcp --syn -m limit --limit $TCPSYNLIMIT --limit-burst $TCPSYNLIMITBURST -j ACCEPT
$IPTABLES -A TCPACCEPT -p tcp --syn -j LSYNFLOOD
$IPTABLES -A TCPACCEPT -p tcp ! --syn -j ACCEPT
#----Create special User-Chains-----#
#CHECKBADFLAG - Kill any Inbound/Outbound TCP-Packets with impossible flag-combinations (Some port-scanners use these, eg. nmap Xmas,Null,etc.-scan)
$IPTABLES -N CHECKBADFLAG
$IPTABLES -A CHECKBADFLAG -p tcp --tcp-flags ALL FIN,URG,PSH -j LBADFLAG
$IPTABLES -A CHECKBADFLAG -p tcp --tcp-flags ALL SYN,RST,ACK,FIN,URG -j LBADFLAG
$IPTABLES -A CHECKBADFLAG -p tcp --tcp-flags ALL ALL -j LBADFLAG
$IPTABLES -A CHECKBADFLAG -p tcp --tcp-flags ALL NONE -j LBADFLAG
$IPTABLES -A CHECKBADFLAG -p tcp --tcp-flags SYN,RST SYN,RST -j LBADFLAG
$IPTABLES -A CHECKBADFLAG -p tcp --tcp-flags SYN,FIN SYN,FIN -j LBADFLAG
#FILTERING FOR SPECIAL PORTS
#Inbound/Outbound SILENTDROPS/REJECTS (Things we don't want in our Logs)
#SMB-Traffic
$IPTABLES -N SMB
$IPTABLES -A SMB -p tcp --dport 137 -j DROP
$IPTABLES -A SMB -p tcp --dport 138 -j DROP
$IPTABLES -A SMB -p tcp --dport 139 -j DROP
$IPTABLES -A SMB -p tcp --dport 445 -j DROP
$IPTABLES -A SMB -p udp --dport 137 -j DROP
$IPTABLES -A SMB -p udp --dport 138 -j DROP
$IPTABLES -A SMB -p udp --dport 139 -j DROP
$IPTABLES -A SMB -p udp --dport 445 -j DROP
$IPTABLES -A SMB -p tcp --sport 137 -j DROP
$IPTABLES -A SMB -p tcp --sport 138 -j DROP
$IPTABLES -A SMB -p tcp --sport 139 -j DROP
$IPTABLES -A SMB -p tcp --sport 445 -j DROP
$IPTABLES -A SMB -p udp --sport 137 -j DROP
$IPTABLES -A SMB -p udp --sport 138 -j DROP
$IPTABLES -A SMB -p udp --sport 139 -j DROP
$IPTABLES -A SMB -p udp --sport 445 -j DROP
#Inbound Special Ports
# SPECIALPORTS
$IPTABLES -N SPECIALPORTS
#Deepthroat Scan
$IPTABLES -A SPECIALPORTS -p tcp --dport 6670 -j LSPECIALPORT
#Subseven Scan
$IPTABLES -A SPECIALPORTS -p tcp --dport 1243 -j LSPECIALPORT
$IPTABLES -A SPECIALPORTS -p udp --dport 1243 -j LSPECIALPORT
$IPTABLES -A SPECIALPORTS -p tcp --dport 27374 -j LSPECIALPORT
$IPTABLES -A SPECIALPORTS -p udp --dport 27374 -j LSPECIALPORT
$IPTABLES -A SPECIALPORTS -p tcp --dport 6711:6713 -j LSPECIALPORT
#Netbus Scan
$IPTABLES -A SPECIALPORTS -p tcp --dport 12345:12346 -j LSPECIALPORT
$IPTABLES -A SPECIALPORTS -p tcp --dport 20034 -j LSPECIALPORT
#Back Orifice scan
$IPTABLES -A SPECIALPORTS -p udp --dport 31337:31338 -j LSPECIALPORT
#X-Win
$IPTABLES -A SPECIALPORTS -p tcp --dport $XWINPORTS -j LSPECIALPORT
#Hack'a'Tack 2000
$IPTABLES -A SPECIALPORTS -p udp --dport 28431 -j LSPECIALPORT
#ICMP/TRACEROUTE FILTERING
#Inbound ICMP/Traceroute
$IPTABLES -N ICMPINBOUND
#Ping Flood protection. Accept $PINGLIMIT echo-requests/sec, rest will be logged/dropped
$IPTABLES -A ICMPINBOUND -p icmp --icmp-type echo-request -m limit --limit $PINGLIMIT --limit-burst $PINGLIMITBURST -j ACCEPT
#
$IPTABLES -A ICMPINBOUND -p icmp --icmp-type echo-request -j LPINGFLOOD
#Block ICMP-Redirects (Should already be catched by sysctl-options, if enabled)
$IPTABLES -A ICMPINBOUND -p icmp --icmp-type redirect -j LDROP
#Block ICMP-Timestamp (Should already be catched by sysctl-options, if enabled)
$IPTABLES -A ICMPINBOUND -p icmp --icmp-type timestamp-request -j LDROP
$IPTABLES -A ICMPINBOUND -p icmp --icmp-type timestamp-reply -j LDROP
#Block ICMP-address-mask (can help to prevent OS-fingerprinting)
$IPTABLES -A ICMPINBOUND -p icmp --icmp-type address-mask-request -j LDROP
$IPTABLES -A ICMPINBOUND -p icmp --icmp-type address-mask-reply -j LDROP
#Allow all other ICMP in
$IPTABLES -A ICMPINBOUND -p icmp -j ACCEPT
#Outbound ICMP/Traceroute
$IPTABLES -N ICMPOUTBOUND
#Block ICMP-Redirects (Should already be catched by sysctl-options, if enabled)
$IPTABLES -A ICMPOUTBOUND -p icmp --icmp-type redirect -j LDROP
#Block ICMP-TTL-Expired
#MS Traceroute (MS uses ICMP instead of UDp for tracert)
$IPTABLES -A ICMPOUTBOUND -p icmp --icmp-type ttl-zero-during-transit -j LDROP
$IPTABLES -A ICMPOUTBOUND -p icmp --icmp-type ttl-zero-during-reassembly -j LDROP
#Block ICMP-Parameter-Problem
$IPTABLES -A ICMPOUTBOUND -p icmp --icmp-type parameter-problem -j LDROP
#Block ICMP-Timestamp (Should already be catched by sysctl-options, if enabled)
$IPTABLES -A ICMPOUTBOUND -p icmp --icmp-type timestamp-request -j LDROP
$IPTABLES -A ICMPOUTBOUND -p icmp --icmp-type timestamp-reply -j LDROP
#Block ICMP-address-mask (can help to prevent OS-fingerprinting)
$IPTABLES -A ICMPOUTBOUND -p icmp --icmp-type address-mask-request -j LDROP
$IPTABLES -A ICMPOUTBOUND -p icmp --icmp-type address-mask-reply -j LDROP
##Accept all other ICMP going out
$IPTABLES -A ICMPOUTBOUND -p icmp -j ACCEPT
#----End User-Chains-----#
echo " --- "
#----Start Ruleset-----#
echo "Implementing firewall rules..."
#################
## INPUT-Chain ## (everything that is addressed to the firewall itself)
#################
##GENERAL Filtering
# Kill INVALID packets (not ESTABLISHED, RELATED or NEW)
# Mato paquetes invalidos (no establecidos,relacionados o nuevos)
$IPTABLES -A INPUT -m state --state INVALID -j LINVALID
# Check TCP-Packets for Bad Flags
$IPTABLES -A INPUT -p tcp -j CHECKBADFLAG
##Packets FROM FIREWALL-BOX ITSELF
#Local IF Acepto todas la conexiones desde la LAN
$IPTABLES -A INPUT -i lo -j ACCEPT
#
#Kill connections to the local interface from the outside
#world (--> Should be already catched by kernel/rp_filter)
# Desde el exterior no se permite acceder al loopback por si acaso
$IPTABLES -A INPUT -d 127.0.0.0/8 -j LREJECT
##Packets FROM INTERNAL NET
$IPTABLES -A INPUT -i $INTIF -s $INTLAN -j ACCEPT
#Kill anything from outside claiming to be from internal
#network (Address-Spoofing --> Should be already catched by rp_filter)
$IPTABLES -A INPUT -s $INTLAN -j LREJECT
##Packets FROM EXTERNAL NET
##ICMP & Traceroute filtering
#Filter ICMP
$IPTABLES -A INPUT -i $EXTIF -p icmp -j ICMPINBOUND
#Block UDP-Traceroute
$IPTABLES -A INPUT -p udp --dport 33434:33523 -j LDROP
# Block Kazza, cerrar conexiones entrantes desde eth1 hacia port
$IPTABLES -A INPUT -p tcp -i $INTIF --dport 41000:41030 -j LDROP
##Silent Drops/Rejects (Things we don't want in our logs)
#Drop all SMB-Traffic
$IPTABLES -A INPUT -i $EXTIF -j SMB
#Silently reject Ident (Don't DROP ident, because of possible delays when establishing an outbound connection)
$IPTABLES -A INPUT -i $EXTIF -p tcp --dport 113 -j REJECT --reject-with tcp-reset
# ftp-data
$IPTABLES -A INPUT -i $EXTIF -p tcp --dport 20 -j TCPACCEPT
# ftp
$IPTABLES -A INPUT -i $EXTIF -p tcp --dport 21 -j TCPACCEPT
# ssh
$IPTABLES -A INPUT -i $EXTIF -p tcp --dport 22 -j TCPACCEPT
# vpn (virtual private network)
#$IPTABLES -A INPUT -i $EXTIF -p tcp --dport 1723 -j TCPACCEPT
#telnet o proxy
#$IPTABLES -A INPUT -i $EXTIF -p tcp --dport 8080 -j TCPACCEPT
# smtp
$IPTABLES -A INPUT -i $EXTIF -p tcp --dport 25 -m state --state NEW -j TCPACCEPT
# DNS
$IPTABLES -A INPUT -i $EXTIF -p tcp --dport 53 -j TCPACCEPT
$IPTABLES -A INPUT -i $EXTIF -p udp --dport 53 -j ACCEPT
# http
$IPTABLES -A INPUT -i $EXTIF -p tcp --dport 80 -j TCPACCEPT
# https
#$IPTABLES -A INPUT -i $EXTIF -p tcp --dport 443 -j TCPACCEPT
# POP-3
#$IPTABLES -A INPUT -i $EXTIF -p tcp --dport 110 -m state --state NEW -j TCPACCEPT
##Separate logging of special portscans/connection attempts
$IPTABLES -A INPUT -i $EXTIF -j SPECIALPORTS
##Allow ESTABLISHED/RELATED connections in
$IPTABLES -A INPUT -i $EXTIF -m state --state ESTABLISHED -j ACCEPT
$IPTABLES -A INPUT -i $EXTIF -p tcp --dport $UNPRIVPORTS -m state --state RELATED -j TCPACCEPT
$IPTABLES -A INPUT -i $EXTIF -p udp --dport $UNPRIVPORTS -m state --state RELATED -j ACCEPT
##Catch all rule
$IPTABLES -A INPUT -j LDROP
##################
## Output-Chain ## (everything that comes directly from the Firewall-Box)
##################
##Packets TO FIREWALL-BOX ITSELF
#Local IF
$IPTABLES -A OUTPUT -o lo -j ACCEPT
##Packets TO INTERNAL NET
#Allow unlimited traffic to internal network using legit addresses
$IPTABLES -A OUTPUT -o $INTIF -d $INTLAN -j ACCEPT
##Packets TO EXTERNAL NET
##ICMP & Traceroute
$IPTABLES -A OUTPUT -o $EXTIF -p icmp -j ICMPOUTBOUND
##Silent Drops/Rejects (Things we don't want in our logs)
#SMB
$IPTABLES -A OUTPUT -o $EXTIF -j SMB
#Ident
$IPTABLES -A OUTPUT -o $EXTIF -p tcp --sport 113 -j REJECT --reject-with tcp-reset
##Public services running ON FIREWALL-BOX (comment out to activate):
# ftp-data
$IPTABLES -A OUTPUT -o $EXTIF -p tcp --sport 20 -j ACCEPT
# ftp
$IPTABLES -A OUTPUT -o $EXTIF -p tcp --sport 21 -j ACCEPT
# ssh
$IPTABLES -A OUTPUT -o $EXTIF -p tcp --sport 22 -m state --state ESTABLISHED -j ACCEPT
# vpn (virtual private network)
#$IPTABLES -A OUTPUT -o $EXTIF -p tcp --sport 1723 -m state --state ESTABLISHED -j ACCEPT
#telnet o proxy
#$IPTABLES -A OUTPUT -o $EXTIF -p tcp --sport 8080 -m state --state ESTABLISHED -j ACCEPT
# smtp
$IPTABLES -A OUTPUT -o $EXTIF -p tcp --sport 25 -m state --state ESTABLISHED -j ACCEPT
# DNS
$IPTABLES -A OUTPUT -o $EXTIF -p tcp --sport 53 -j ACCEPT
$IPTABLES -A OUTPUT -o $EXTIF -p udp --sport 53 -j ACCEPT
# http
$IPTABLES -A OUTPUT -o $EXTIF -p tcp --sport 80 -m state --state ESTABLISHED -j ACCEPT
# https
#$IPTABLES -A OUTPUT -o $EXTIF -p tcp --sport 443 -m state --state ESTABLISHED -j ACCEPT
# POP-3
#$IPTABLES -A OUTPUT -o $EXTIF -p tcp --sport 110 -m state --state ESTABLISHED -j ACCEPT
##Accept all tcp/udp traffic on unprivileged ports going out
$IPTABLES -A OUTPUT -o $EXTIF -s $EXTIP -p tcp --sport $UNPRIVPORTS -j ACCEPT
$IPTABLES -A OUTPUT -o $EXTIF -s $EXTIP -p udp --sport $UNPRIVPORTS -j ACCEPT
##Catch all rule
$IPTABLES -A OUTPUT -j LDROP
####################
## FORWARD-Chain ## (everything that passes the firewall)
####################
##GENERAL Filtering
#Kill invalid packets (not ESTABLISHED, RELATED or NEW)
$IPTABLES -A FORWARD -m state --state INVALID -j LINVALID
# Check TCP-Packets for Bad Flags
$IPTABLES -A FORWARD -p tcp -j CHECKBADFLAG
##Filtering FROM INTERNAL NET
##Silent Drops/Rejects (Things we don't want in our logs)
#SMB
$IPTABLES -A FORWARD -o $EXTIF -j SMB
##Special Drops/Rejects
# - To be done -
##Filter for some Trojans communicating to outside
# - To be done -
##Port-Forwarding from Ports < 1024 [outbound] (--> Also see chain PREROUTING)
#$IPTABLES -A FORWARD -o $EXTIF -s $HTTPIP -p tcp --sport 80 -j ACCEPT
##Allow all other forwarding (from Ports > 1024) from Internal Net to External Net
$IPTABLES -A FORWARD -i $INTIF -o $EXTIF -s $INTLAN -p tcp --sport $UNPRIVPORTS -j ACCEPT
$IPTABLES -A FORWARD -i $INTIF -o $EXTIF -s $INTLAN -p udp --sport $UNPRIVPORTS -j ACCEPT
$IPTABLES -A FORWARD -i $INTIF -o $EXTIF -s $INTLAN -p icmp -j ACCEPT
##Filtering FROM EXTERNAL NET
##Silent Drops/Rejects (Things we don't want in our logs)
#SMB
$IPTABLES -A FORWARD -i $EXTIF -j SMB
##Allow replies coming in
$IPTABLES -A FORWARD -i $EXTIF -m state --state ESTABLISHED -j ACCEPT
$IPTABLES -A FORWARD -i $EXTIF -p tcp --dport $UNPRIVPORTS -m state --state RELATED -j TCPACCEPT
$IPTABLES -A FORWARD -i $EXTIF -p udp --dport $UNPRIVPORTS -m state --state RELATED -j ACCEPT
$IPTABLES -A FORWARD -i $EXTIF -p icmp -m state --state RELATED -j ACCEPT
##Port-Forwarding [inbound] (--> Also see chain PREROUTING)
##Catch all rule/Deny every other forwarding
$IPTABLES -A FORWARD -j LDROP
################
## PREROUTING ##
################
##Port-Forwarding (--> Also see chain FORWARD)
##EXTIF = eth0 EXTIP = 200.40.171.158
##INTIF = eth1 INTIP = 192.168.1.9
# Para el puerto 8080
# -----------------
#$IPTABLES -A FORWARD -j ACCEPT -p tcp --dport 8080
#$IPTABLES -t nat -A PREROUTING -i $EXTIF -p tcp -d 200.40.171.158 --dport 8080 -j DNAT --to $HTTPIP:80
# -----------------
$IPTABLES -A FORWARD -j ACCEPT -p tcp --dport 22
$IPTABLES -t nat -A PREROUTING -i $EXTIF -p tcp --dport 22 -j DNAT --to 192.168.1.8:22
# Redirecciono al puerto 3128 todos los paquetes que entran por eth1 y con
# destino puerto 80 (proxy transparente)
$IPTABLES -A FORWARD -p tcp -s 192.168.1.0/24 -d ! 192.168.1.9 --dport 3128 -j DROP
$IPTABLES -t nat -A PREROUTING -i $INTIF -p tcp --dport 80 -j REDIRECT --to-port 3128
###################
## POSTROUTING ##
###################
#$IPTABLES -t nat -A POSTROUTING -o $EXTIP -p tcp -j SNAT --to 192.168.1.9
# Masquerade from Internal Net to External Net (real)
$IPTABLES -A POSTROUTING -t nat -o $EXTIF -j MASQUERADE
echo "...done NO MASQ"
>
> saludos, velkro.
>
> ----- Original Message -----
> From: "Walter G Osoria" <wosoria@adinet.com.uy>
> To: <debian-user-spanish@lists.debian.org>
> Sent: Wednesday, February 02, 2005 09:38
> Subject: redireccionar ssh a la lan
>
> saludos a todos, quiero redireccionar desde el exterior a un pc
> de la lan, tengo la siguientes reglas de iptables
>
> $IPTABLES -t nat -A PREROUTING -i $EXTIF -p tcp --dport 22 -m state
> --state NEW -j DNAT --to $PCLAN:22
>
> $IPTABLES -A FORWARD -i $EXTIF -m state --state ESTABLISHED,RELATED -j
> ACCEPT -p tcp --dport 22
>
> pero no me funciona, puede ser que al conectarme de la misma lan me
> esté dejando en el servidor y no me redireccione al pc que quiero ?
>
> $IPTABLES -t nat -A POSTROUTING -s $LAN/24 -o $EXTIF -j MASQUERADE
>
> o sino que este enmascarando la red mal ? un abrazo y gracias
>
>
>
>
> --
> To UNSUBSCRIBE, email to debian-user-spanish-REQUEST@lists.debian.org
> with a subject of "unsubscribe". Trouble? Contact listmaster@lists.debian.org
--
______________________________________________
Walter Osoria - Debian GNU/Linux 3.0
wosoria@adinet.com.uy - LIcq 2277064
Linux registered user #124360
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