451 lines
13 KiB
Bash
451 lines
13 KiB
Bash
#!/bin/bash
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# chkconfig: - 16 84
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# description: Automates a packet filtering firewall with iptables.
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# File: /etc/init.d/firewall
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. /etc/init.d/functions
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. /etc/sysconfig/firewall.conf
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MASQCONF="/etc/sysconfig/firewall-masquerade.conf"
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FWDCONF="/etc/sysconfig/firewall-forward.conf"
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QOSCONF="/etc/sysconfig/firewall-qos.conf"
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# erlaubt immer SSH zugriff aus internen netzen
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DEBUG="no"
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modprobe=`which modprobe`
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ipt=`which iptables`
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tc=`which tc`
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# ulog target
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ULOG="ULOG --ulog-cprange 128 --ulog-prefix"
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case "$1" in
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start)
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echo "Setting up firewall"
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touch /var/lock/subsys/firewall
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# Flush all tables and delete user chains
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$ipt -F -t filter
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$ipt -F -t nat
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$ipt -F -t mangle
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$ipt -X -t filter
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$ipt -X -t nat
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$ipt -X -t mangle
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# user chains
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$ipt -N ext-in
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$ipt -N fwd-out
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$ipt -N ext-out
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$ipt -t nat -N ext-in
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$ipt -t mangle -N ext-in
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$ipt -t mangle -N ext-out
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# USER-CHAIN: drop/reject unwanted packets from inet
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$ipt -N droprej
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$ipt -A droprej -p tcp -j REJECT --reject-with tcp-reset
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$ipt -A droprej -p udp -j REJECT
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$ipt -A droprej -j DROP
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# USER-CHAIN: log & drop private IPs from/to inet
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$ipt -t mangle -N logdrop
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$ipt -t mangle -A logdrop -j $ULOG ext-drop
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$ipt -t mangle -A logdrop -j DROP
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# Allow loopback
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$ipt -A INPUT -i lo -j ACCEPT
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$ipt -A OUTPUT -o lo -j ACCEPT
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# debugging
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if [ "$DEBUG" == "yes" ]; then
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$ipt -A INPUT -p tcp --dport 22 -j ACCEPT
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$ipt -A OUTPUT -p tcp --sport 22 -j ACCEPT
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fi
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# already accepted traffic
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$ipt -A FORWARD -m state --state ESTABLISHED,RELATED -j ACCEPT
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# internal nets
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for i in $INT_NUMS; do
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eval dev=\${INT_DEV_${i}}
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eval nets=\${INT_NET_${i}}
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eval opts=\${INT_OPT_${i}}
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realdev=`echo $dev | cut -d":" -f1`
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# options parsing
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for opt in $opts; do
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case "$opt" in
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# Allow bridging
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BRIDGE)
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$ipt -A FORWARD -i $dev -o $dev -j ACCEPT
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;;
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# allow traffic on internal net
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INTERNAL)
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for net in $nets; do
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$ipt -A INPUT -i $realdev -s $net -j ACCEPT
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$ipt -A OUTPUT -o $realdev -d $net -j ACCEPT
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done
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;;
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# Allow traffic to external net
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EXTERNAL)
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for net in $nets; do
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$ipt -A FORWARD -i $dev -s $net -j fwd-out
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done
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;;
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# Allow Routing to other internal nets
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ROUTE)
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for i2 in $INT_NUMS; do
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eval dev2=\${INT_DEV_${i2}}
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eval nets2=\${INT_NET_${i2}}
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realdev2=`echo $dev2 | cut -d":" -f1`
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for net in $nets; do
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for net2 in $nets2; do
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if [ "$net" != "$net2" ] || [ "$realdev" != "$realdev2" ]; then
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$ipt -A FORWARD -i $realdev -o $realdev2 -s $net -d $net2 -j ACCEPT
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fi
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done
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done
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done
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;;
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# Masquerade all connections through this interface and allow external portforwardings
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MASQ)
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for net in $nets; do
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$ipt -t nat -A PREROUTING -i $dev -j ext-in
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$ipt -A INPUT -i $dev -s $net -j ext-in
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$ipt -A OUTPUT -o $dev -d $net -j ext-out
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$ipt -A FORWARD -i $dev -s $net -m conntrack --ctstate SNAT -j ACCEPT
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$ipt -t nat -A POSTROUTING -o $dev -j MASQUERADE
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done
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;;
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# redirect web traffic to squid
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TSQUID)
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if [ -z "$squid_table" ]; then
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squid_table=ok
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# squid table
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$ipt -t nat -N squid
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fi
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$ipt -t nat -A PREROUTING -i $dev -p tcp --dport 80 -j squid
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# no squid between nets on this interface
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for neta in $nets; do
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for netb in $nets; do
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$ipt -t nat -A squid -i $dev -s $neta -d $netb -j ACCEPT
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done
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done
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$ipt -t nat -A squid -i $dev -p tcp -j REDIRECT --to-ports 3128
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;;
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# Allow dhcpd traffic
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DHCP)
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$ipt -A INPUT -i $dev -p udp --sport 67:68 --dport 67:68 -j ACCEPT
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$ipt -A OUTPUT -o $dev -p udp --sport 67:68 --dport 67:68 -j ACCEPT
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;;
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# honeypot target/net
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HONEYPOT)
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if [ -z "$hpot_table" ]; then
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hpot_table=ok
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# Allow nothing
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$ipt -N hpot-in
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$ipt -A hpot-in -j droprej
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# Allow ftp and dns to external net
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$ipt -N hpot-fwd
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$ipt -A hpot-fwd -p udp --dport 53 -j ACCEPT
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$ipt -A hpot-fwd -p tcp --dport 21 -j ACCEPT
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$ipt -A hpot-fwd -j droprej
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# Allow icmp, tcp-rst from localhost (answer to drop-rej in hpot-fwd)
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$ipt -N hpot-out
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$ipt -A hpot-out -p tcp --tcp-flags RST RST -j ACCEPT
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$ipt -A hpot-out -p icmp -j ACCEPT
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$ipt -A hpot-out -j DROP
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# ratelimit everything
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$ipt -t mangle -N hpot-in
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$ipt -t mangle -A hpot-in -m limit --limit $HONEYPOT_RATE_TO -j ACCEPT
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$ipt -t mangle -A hpot-in -j DROP
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$ipt -t mangle -N hpot-out
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$ipt -t mangle -A hpot-out -m limit --limit $HONEYPOT_RATE_FROM -j ACCEPT
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$ipt -t mangle -A hpot-out -j DROP
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fi
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for net in $nets; do
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$ipt -t mangle -A PREROUTING -i $dev -s $net -j hpot-in
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$ipt -A INPUT -i $dev -s $net -j hpot-in
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$ipt -A FORWARD -i $dev -s $net -j hpot-fwd
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$ipt -A OUTPUT -o $dev -d $net -j hpot-out
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$ipt -t mangle -A POSTROUTING -o $dev -d $net -j hpot-out
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done
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;;
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esac
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done
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done
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# external nets
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for dev in $EXT_DEVS; do
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$ipt -A INPUT -i $dev -j ext-in
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$ipt -A FORWARD -i $dev -m conntrack --ctstate DNAT -j ACCEPT
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$ipt -A OUTPUT -o $dev -j ext-out
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# external in/out (dropping internal nets)
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$ipt -t mangle -A PREROUTING -i $dev -j ext-in
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$ipt -t mangle -A POSTROUTING -o $dev -j ext-out
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# external in/out (portforwarding)
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$ipt -t nat -A PREROUTING -i $dev -j ext-in
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# used to overcome criminally brain-dead ISPs or servers which block ICMP Fragmentation Needed packets
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$ipt -t mangle -A FORWARD -o $dev -p tcp --tcp-flags SYN,RST SYN -j TCPMSS --clamp-mss-to-pmtu
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# masquerade everything passing ext device
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$ipt -t nat -A POSTROUTING -o $dev -j MASQUERADE
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done
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# reject the rest
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$ipt -A INPUT -j $ULOG input
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$ipt -A INPUT -j droprej
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$ipt -A FORWARD -j $ULOG forward
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$ipt -A FORWARD -j droprej
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$ipt -A OUTPUT -j $ULOG output
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$ipt -A OUTPUT -j droprej
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# drop restriced nets
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for net in $EXT_DENIED; do
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$ipt -t mangle -A ext-in -s $net -j logdrop
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$ipt -t mangle -A ext-out -d $net -j logdrop
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done
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# allow own traffic
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$ipt -A ext-in -m state --state ESTABLISHED,RELATED -j ACCEPT
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# block windows traffic
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if [ "$EXT_BLOCK_WINDOWS" == "yes" ]; then
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for chain in ext-in fwd-out ext-out; do
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$ipt -A $chain -p tcp --dport 135:139 -j droprej
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$ipt -A $chain -p udp --dport 135:139 -j droprej
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$ipt -A $chain -p tcp --dport 445 -j droprej
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done
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fi
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# masqerading list (masquerade.conf)
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grep '^[^#]' $MASQCONF | while read ip proto port; do
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if [ "$proto" == "all" ]; then
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$ipt -A fwd-out -s $ip -j ACCEPT
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elif [ "$proto" == "tcp" -o "$proto" == "udp" ]; then
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$ipt -A fwd-out -s $ip -p $proto --dport $port -j ACCEPT
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else
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$ipt -A fwd-out -s $ip -p $proto -j ACCEPT
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fi
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done
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# log & drop/reject unwanted packets from internal to inet
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$ipt -A fwd-out -j $ULOG fwd-out
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$ipt -A fwd-out -j droprej
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# allow ipv6 proto (tunnel)
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for ip in "$EXT_SIT_TUNNEL_IP"; do
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$ipt -A ext-in -p 41 -s $ip -j ACCEPT
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$ipt -A ext-out -p 41 -d $ip -j ACCEPT
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done
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# port-forwarding list (forward.conf)
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grep '^[^#]' $FWDCONF | while read ip proto port dport; do
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# if ip=127.0.0.1 then do not forwarding
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if [ "$ip" == "127.0.0.1" ]; then
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if [ -z "$dport" ]; then
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dport=$port
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else
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$ipt -t nat -A ext-in -p $proto --dport $port -j REDIRECT --to-ports $dport
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fi
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$ipt -A ext-in -p $proto --dport $dport -j ACCEPT
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else
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# if no dport is given, dport = port
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if [ -z "$dport" ]; then
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dport=`echo $port | tr ':' '-'`
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else
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dport=`echo $dport | tr ':' '-'`
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fi
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$ipt -t nat -A ext-in -p $proto --dport $port -j DNAT --to ${ip}:${dport}
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fi
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done
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# allow some icmp-echo-requests
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$ipt -A ext-in -p icmp --icmp-type echo-request -m limit --limit 5/s -m length --length 0:128 -j ACCEPT
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$ipt -A ext-in -p icmp --icmp-type echo-request -j DROP
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# log low ports and block the rest
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$ipt -A ext-in -p tcp --dport 1024:65535 -j droprej
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$ipt -A ext-in -p udp --dport 1024:65535 -j droprej
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$ipt -A ext-in -j $ULOG ext-in
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$ipt -A ext-in -j droprej
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# final catch ext-out
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$ipt -A ext-out -p tcp -j ACCEPT
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$ipt -A ext-out -p udp -j ACCEPT
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$ipt -A ext-out -p icmp -j ACCEPT
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$ipt -A ext-out -j $ULOG ext-out
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$ipt -A ext-out -j droprej
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# qos-stuff
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$ipt -t mangle -N qosmark
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$ipt -t mangle -A qosmark -j MARK --set-mark 22
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# qos-regeln
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grep '^[^#]' $QOSCONF | while read mark proto sport dport; do
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if [ "$proto" == "tcp" -o "$proto" == "udp" ]; then
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if [ -z "$sport" -o "$sport" == "any" ]; then
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sport="0:65535"
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fi
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if [ -z "$dport" -o "$dport" == "any" ]; then
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dport="0:65535"
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fi
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$ipt -t mangle -A qosmark -p $proto --sport $sport --dport $dport -j MARK --set-mark $mark
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else
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$ipt -t mangle -A qosmark -p $proto -j MARK --set-mark $mark
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fi
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done
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# safe mark
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$ipt -t mangle -A qosmark -j CONNMARK --save-mark
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$ipt -t mangle -A qosmark -j RETURN
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# call qosmark from prerouting and postrouting for new connections only
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$ipt -t mangle -A ext-in -j CONNMARK --restore-mark
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$ipt -t mangle -A ext-in -m mark --mark 0 -j qosmark
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$ipt -t mangle -A ext-out -j CONNMARK --restore-mark
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$ipt -t mangle -A ext-out -m mark --mark 0 -j qosmark
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# small acks must be fast (per packet, not per flow)
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$ipt -t mangle -A ext-in -p tcp --tcp-flags ACK ACK -m length --length 0:65 -j MARK --set-mark 20
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$ipt -t mangle -A ext-out -p tcp --tcp-flags ACK ACK -m length --length 0:65 -j MARK --set-mark 20
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# kernel tweaks
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echo 1 > /proc/sys/net/ipv4/ip_forward
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echo 1 > /proc/sys/net/ipv4/netfilter/ip_conntrack_log_invalid > /dev/null 2>&1
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# add. modules
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$modprobe ip_nat_ftp
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success "Setting up firewall"
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echo
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;;
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stop)
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echo -n "Shutting down firewall"
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rm /var/lock/subsys/firewall
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# Flush all tables
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iptables -F -t filter
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iptables -F -t nat
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iptables -F -t mangle
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iptables -X -t filter
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iptables -X -t nat
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iptables -X -t mangle
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success "Shutting down firewall"
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echo
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;;
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restart)
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$0 stop
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$0 start
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;;
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status)
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{
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echo "==============================================="
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echo "FILTER:"
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$ipt -L -nv -t filter
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echo
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echo "==============================================="
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echo "NAT:"
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$ipt -L -nv -t nat
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echo
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echo "==============================================="
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echo "MANGLE:"
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$ipt -L -nv -t mangle
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echo
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} | less -S -#4
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;;
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start-qos)
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$0 stop-qos
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echo -n "Setting up QoS"
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$tc qdisc add dev $QOS_DEV root handle 1: htb default 22
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$tc class add dev $QOS_DEV parent 1: classid 1:1 htb rate ${QOS_RATEUP}kbit
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$tc class add dev $QOS_DEV parent 1:1 classid 1:20 htb rate $[$QOS_RATEUP/10]kbit ceil $[$QOS_RATEUP/10*3]kbit prio 4
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$tc class add dev $QOS_DEV parent 1:1 classid 1:21 htb rate $[$QOS_RATEUP/10]kbit ceil $[$QOS_RATEUP/10*5]kbit prio 2
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$tc class add dev $QOS_DEV parent 1:1 classid 1:22 htb rate $[$QOS_RATEUP/10]kbit ceil $[$QOS_RATEUP/10*5]kbit prio 1
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$tc class add dev $QOS_DEV parent 1:1 classid 1:23 htb rate $[$QOS_RATEUP/10]kbit ceil $[$QOS_RATEUP/10*8]kbit prio 0
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$tc qdisc add dev $QOS_DEV parent 1:20 handle 20: sfq perturb 10
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$tc qdisc add dev $QOS_DEV parent 1:21 handle 21: sfq perturb 10
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$tc qdisc add dev $QOS_DEV parent 1:22 handle 22: sfq perturb 10
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$tc qdisc add dev $QOS_DEV parent 1:23 handle 23: sfq perturb 10
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$tc filter add dev $QOS_DEV parent 1:0 prio 0 protocol ip handle 20 fw flowid 1:20
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$tc filter add dev $QOS_DEV parent 1:0 prio 0 protocol ip handle 21 fw flowid 1:21
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$tc filter add dev $QOS_DEV parent 1:0 prio 0 protocol ip handle 22 fw flowid 1:22
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$tc filter add dev $QOS_DEV parent 1:0 prio 0 protocol ip handle 23 fw flowid 1:23
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success "Setting up QoS"
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echo
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;;
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stop-qos)
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echo -n "Shutting down QoS"
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$tc qdisc del dev $QOS_DEV root 2> /dev/null
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success "Shutting down QoS"
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echo
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;;
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status-qos)
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{
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echo "==============================================="
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echo "QDISC:"
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$tc -s -d qdisc show dev $QOS_DEV
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echo
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echo "==============================================="
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echo "CLASS:"
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$tc -s -d class show dev $QOS_DEV
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echo
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echo "==============================================="
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echo "FILTER:"
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$tc -s -d filter show dev $QOS_DEV
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echo
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} | less -S -#4
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;;
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*)
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echo "Usage: $0 {start|stop|restart|status|start-qos|stop-qos|status-qos}"
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exit 1
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;;
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esac
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