Iptables firewall automatic setting script

We recommend a good iptables-shell script to free you from the troublesome iptables configuration. I am not sure who the script author is, so I deleted the version declaration. system: centos5.9 script content: viiptables. sh #! /Bin/sh # -------------------------------------------------- it's good to give it to you. Iptables-Shell scripts help you solve the problem IptablesI am not sure who the script author is, so I deleted the version declaration.
System: Centos5.9
Script content:
Vi iptables. sh

#!/bin/sh#------------------------------------------------------------------------------# For debugging use iptables -v.IPTABLES="/sbin/iptables"IP6TABLES="/sbin/ip6tables"MODPROBE="/sbin/modprobe"RMMOD="/sbin/rmmod"ARP="/usr/sbin/arp"# Logging options.#------------------------------------------------------------------------------LOG="LOG --log-level debug --log-tcp-sequence --log-tcp-options"LOG="$LOG --log-ip-options"# Defaults for rate limiting#------------------------------------------------------------------------------RLIMIT="-m limit --limit 3/s --limit-burst 8"# Unprivileged ports.#------------------------------------------------------------------------------PHIGH="1024:65535"PSSH="1000:1023"# Load required kernel modules#------------------------------------------------------------------------------$MODPROBE ip_conntrack_ftp$MODPROBE ip_conntrack_irc# Mitigate ARP spoofing/poisoning and similar attacks.#------------------------------------------------------------------------------# Hardcode static ARP cache entries here# $ARP -s IP-ADDRESS MAC-ADDRESS# Kernel configuration.#------------------------------------------------------------------------------# Disable IP forwarding.# On => Off = (reset)echo 1 > /proc/sys/net/ipv4/ip_forwardecho 0 > /proc/sys/net/ipv4/ip_forward# Enable IP spoofing protectionfor i in /proc/sys/net/ipv4/conf/*/rp_filter; do echo 1 > $i; done# Protect against SYN flood attacksecho 1 > /proc/sys/net/ipv4/tcp_syncookies# Ignore all incoming ICMP echo requestsecho 0 > /proc/sys/net/ipv4/icmp_echo_ignore_all# Ignore ICMP echo requests to broadcastecho 1 > /proc/sys/net/ipv4/icmp_echo_ignore_broadcasts# Log packets with impossible addresses.for i in /proc/sys/net/ipv4/conf/*/log_martians; do echo 1 > $i; done# Don't log invalid responses to broadcastecho 1 > /proc/sys/net/ipv4/icmp_ignore_bogus_error_responses# Don't accept or send ICMP redirects.for i in /proc/sys/net/ipv4/conf/*/accept_redirects; do echo 0 > $i; donefor i in /proc/sys/net/ipv4/conf/*/send_redirects; do echo 0 > $i; done# Don't accept source routed packets.for i in /proc/sys/net/ipv4/conf/*/accept_source_route; do echo 0 > $i; done# Disable multicast routing##for i in /proc/sys/net/ipv4/conf/*/mc_forwarding; do echo 0 > $i; done# Disable proxy_arp.for i in /proc/sys/net/ipv4/conf/*/proxy_arp; do echo 0 > $i; done# Enable secure redirects, i.e. only accept ICMP redirects for gateways# Helps against MITM attacks.for i in /proc/sys/net/ipv4/conf/*/secure_redirects; do echo 1 > $i; done# Disable bootp_relayfor i in /proc/sys/net/ipv4/conf/*/bootp_relay; do echo 0 > $i; done# Default policies.#------------------------------------------------------------------------------# Drop everything by default.$IPTABLES -P INPUT DROP$IPTABLES -P FORWARD DROP$IPTABLES -P OUTPUT DROP# Set the nat/mangle/raw tables' chains to ACCEPT$IPTABLES -t nat -P PREROUTING ACCEPT$IPTABLES -t nat -P OUTPUT ACCEPT$IPTABLES -t nat -P POSTROUTING ACCEPT$IPTABLES -t mangle -P PREROUTING ACCEPT$IPTABLES -t mangle -P INPUT ACCEPT$IPTABLES -t mangle -P FORWARD ACCEPT$IPTABLES -t mangle -P OUTPUT ACCEPT$IPTABLES -t mangle -P POSTROUTING ACCEPT# Cleanup.#------------------------------------------------------------------------------# Delete all$IPTABLES -F$IPTABLES -t nat -F$IPTABLES -t mangle -F# Delete all$IPTABLES -X$IPTABLES -t nat -X$IPTABLES -t mangle -X# Zero all packets and counters.$IPTABLES -Z$IPTABLES -t nat -Z$IPTABLES -t mangle -Z# Completely disable IPv6.#------------------------------------------------------------------------------# Block all IPv6 traffic# If the ip6tables command is available, try to block all IPv6 traffic.if test -x $IP6TABLES; then# Set the default policies# drop everything$IP6TABLES -P INPUT DROP 2>/dev/null$IP6TABLES -P FORWARD DROP 2>/dev/null$IP6TABLES -P OUTPUT DROP 2>/dev/null# The mangle table can pass everything$IP6TABLES -t mangle -P PREROUTING ACCEPT 2>/dev/null$IP6TABLES -t mangle -P INPUT ACCEPT 2>/dev/null$IP6TABLES -t mangle -P FORWARD ACCEPT 2>/dev/null$IP6TABLES -t mangle -P OUTPUT ACCEPT 2>/dev/null$IP6TABLES -t mangle -P POSTROUTING ACCEPT 2>/dev/null# Delete all rules.$IP6TABLES -F 2>/dev/null$IP6TABLES -t mangle -F 2>/dev/null# Delete all chains.$IP6TABLES -X 2>/dev/null$IP6TABLES -t mangle -X 2>/dev/null# Zero all packets and counters.$IP6TABLES -Z 2>/dev/null$IP6TABLES -t mangle -Z 2>/dev/nullfi# Custom user-defined chains.#------------------------------------------------------------------------------# LOG packets, then ACCEPT.$IPTABLES -N ACCEPTLOG$IPTABLES -A ACCEPTLOG -j $LOG $RLIMIT --log-prefix "ACCEPT "$IPTABLES -A ACCEPTLOG -j ACCEPT# LOG packets, then DROP.$IPTABLES -N DROPLOG$IPTABLES -A DROPLOG -j $LOG $RLIMIT --log-prefix "DROP "$IPTABLES -A DROPLOG -j DROP# LOG packets, then REJECT.# TCP packets are rejected with a TCP reset.$IPTABLES -N REJECTLOG$IPTABLES -A REJECTLOG -j $LOG $RLIMIT --log-prefix "REJECT "$IPTABLES -A REJECTLOG -p tcp -j REJECT --reject-with tcp-reset$IPTABLES -A REJECTLOG -j REJECT# Only allows RELATED ICMP types# (destination-unreachable, time-exceeded, and parameter-problem).# TODO: Rate-limit this traffic?# TODO: Allow fragmentation-needed?# TODO: Test.$IPTABLES -N RELATED_ICMP$IPTABLES -A RELATED_ICMP -p icmp --icmp-type destination-unreachable -j ACCEPT$IPTABLES -A RELATED_ICMP -p icmp --icmp-type time-exceeded -j ACCEPT$IPTABLES -A RELATED_ICMP -p icmp --icmp-type parameter-problem -j ACCEPT$IPTABLES -A RELATED_ICMP -j DROPLOG# Make It Even Harder To Multi-PING$IPTABLES  -A INPUT -p icmp -m limit --limit 1/s --limit-burst 2 -j ACCEPT$IPTABLES  -A INPUT -p icmp -m limit --limit 1/s --limit-burst 2 -j LOG --log-prefix PING-DROP:$IPTABLES  -A INPUT -p icmp -j DROP$IPTABLES  -A OUTPUT -p icmp -j ACCEPT# Only allow the minimally required/recommended parts of ICMP. Block the rest.#------------------------------------------------------------------------------# TODO: This section needs a lot of testing!# First, drop all fragmented ICMP packets (almost always malicious).$IPTABLES -A INPUT -p icmp --fragment -j DROPLOG$IPTABLES -A OUTPUT -p icmp --fragment -j DROPLOG$IPTABLES -A FORWARD -p icmp --fragment -j DROPLOG# Allow all ESTABLISHED ICMP traffic.$IPTABLES -A INPUT -p icmp -m state --state ESTABLISHED -j ACCEPT $RLIMIT$IPTABLES -A OUTPUT -p icmp -m state --state ESTABLISHED -j ACCEPT $RLIMIT# Allow some parts of the RELATED ICMP traffic, block the rest.$IPTABLES -A INPUT -p icmp -m state --state RELATED -j RELATED_ICMP $RLIMIT$IPTABLES -A OUTPUT -p icmp -m state --state RELATED -j RELATED_ICMP $RLIMIT# Allow incoming ICMP echo requests (ping), but only rate-limited.$IPTABLES -A INPUT -p icmp --icmp-type echo-request -j ACCEPT $RLIMIT# Allow outgoing ICMP echo requests (ping), but only rate-limited.$IPTABLES -A OUTPUT -p icmp --icmp-type echo-request -j ACCEPT $RLIMIT# Drop any other ICMP traffic.$IPTABLES -A INPUT -p icmp -j DROPLOG$IPTABLES -A OUTPUT -p icmp -j DROPLOG$IPTABLES -A FORWARD -p icmp -j DROPLOG# Selectively allow certain special types of traffic.#------------------------------------------------------------------------------# Allow loopback interface to do anything.$IPTABLES -A INPUT -i lo -j ACCEPT$IPTABLES -A OUTPUT -o lo -j ACCEPT# Allow incoming connections related to existing allowed connections.$IPTABLES -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT# Allow outgoing connections EXCEPT invalid$IPTABLES -A OUTPUT -m state --state NEW,ESTABLISHED,RELATED -j ACCEPT# Miscellaneous.#------------------------------------------------------------------------------# We don't care about Milkosoft, Drop SMB/CIFS/etc..$IPTABLES -A INPUT -p tcp -m multiport --dports 135,137,138,139,445,1433,1434 -j DROP$IPTABLES -A INPUT -p udp -m multiport --dports 135,137,138,139,445,1433,1434 -j DROP# Explicitly drop invalid incoming traffic$IPTABLES -A INPUT -m state --state INVALID -j DROP# Drop invalid outgoing traffic, too.$IPTABLES -A OUTPUT -m state --state INVALID -j DROP# If we would use NAT, INVALID packets would pass - BLOCK them anyways$IPTABLES -A FORWARD -m state --state INVALID -j DROP# PORT Scanners (stealth also)$IPTABLES -A INPUT -m state --state NEW -p tcp --tcp-flags ALL ALL -j DROP$IPTABLES -A INPUT -m state --state NEW -p tcp --tcp-flags ALL NONE -j DROP# TODO: Some more anti-spoofing rules? For example:# $IPTABLES -A INPUT -p tcp --tcp-flags ALL FIN,URG,PSH -j DROP# $IPTABLES -A INPUT -p tcp --tcp-flags SYN,RST SYN,RST -j DROP# $IPTABLES -A INPUT -p tcp --tcp-flags SYN,FIN SYN,FIN -j DROP$IPTABLES -N SYN_FLOOD$IPTABLES -A INPUT -p tcp --syn -j SYN_FLOOD$IPTABLES -A SYN_FLOOD -m limit --limit 2/s --limit-burst 6 -j RETURN$IPTABLES -A SYN_FLOOD -j DROP# TODO: Block known-bad IPs (see http://www.dshield.org/top10.php).# $IPTABLES -A INPUT -s INSERT-BAD-IP-HERE -j DROPLOG# Drop any traffic from IANA-reserved IPs.#------------------------------------------------------------------------------$IPTABLES -A INPUT -s 0.0.0.0/7 -j DROP$IPTABLES -A INPUT -s 2.0.0.0/8 -j DROP$IPTABLES -A INPUT -s 5.0.0.0/8 -j DROP$IPTABLES -A INPUT -s 7.0.0.0/8 -j DROP$IPTABLES -A INPUT -s 10.0.0.0/8 -j DROP$IPTABLES -A INPUT -s 23.0.0.0/8 -j DROP$IPTABLES -A INPUT -s 27.0.0.0/8 -j DROP$IPTABLES -A INPUT -s 31.0.0.0/8 -j DROP$IPTABLES -A INPUT -s 36.0.0.0/7 -j DROP$IPTABLES -A INPUT -s 39.0.0.0/8 -j DROP$IPTABLES -A INPUT -s 42.0.0.0/8 -j DROP$IPTABLES -A INPUT -s 49.0.0.0/8 -j DROP$IPTABLES -A INPUT -s 50.0.0.0/8 -j DROP$IPTABLES -A INPUT -s 77.0.0.0/8 -j DROP$IPTABLES -A INPUT -s 78.0.0.0/7 -j DROP$IPTABLES -A INPUT -s 92.0.0.0/6 -j DROP$IPTABLES -A INPUT -s 96.0.0.0/4 -j DROP$IPTABLES -A INPUT -s 112.0.0.0/5 -j DROP$IPTABLES -A INPUT -s 120.0.0.0/8 -j DROP$IPTABLES -A INPUT -s 169.254.0.0/16 -j DROP$IPTABLES -A INPUT -s 172.16.0.0/12 -j DROP$IPTABLES -A INPUT -s 173.0.0.0/8 -j DROP$IPTABLES -A INPUT -s 174.0.0.0/7 -j DROP$IPTABLES -A INPUT -s 176.0.0.0/5 -j DROP$IPTABLES -A INPUT -s 184.0.0.0/6 -j DROP$IPTABLES -A INPUT -s 192.0.2.0/24 -j DROP$IPTABLES -A INPUT -s 197.0.0.0/8 -j DROP$IPTABLES -A INPUT -s 198.18.0.0/15 -j DROP$IPTABLES -A INPUT -s 223.0.0.0/8 -j DROP$IPTABLES -A INPUT -s 224.0.0.0/3 -j DROP# Selectively allow certain outbound connections, block the rest.#------------------------------------------------------------------------------# Allow outgoing DNS requests. Few things will work without this.$IPTABLES -A OUTPUT -m state --state NEW -p udp --dport 53 -j ACCEPT$IPTABLES -A OUTPUT -m state --state NEW -p tcp --dport 53 -j ACCEPT# Allow outgoing HTTP requests. Unencrypted, use with care.$IPTABLES -A OUTPUT -m state --state NEW -p tcp --dport 80 -j ACCEPT# Allow outgoing HTTPS requests.$IPTABLES -A OUTPUT -m state --state NEW -p tcp --dport 443 -j ACCEPT# Allow outgoing SMTPS requests. Do NOT allow unencrypted SMTP!# $IPTABLES -A OUTPUT -m state --state NEW -p tcp --dport 465 -j ACCEPT# Allow outgoing "submission" (RFC 2476) requests.$IPTABLES -A OUTPUT -m state --state NEW -p tcp --dport 587 -j ACCEPT# Allow outgoing POP3S requests.$IPTABLES -A OUTPUT -m state --state NEW -p tcp --dport 995 -j ACCEPT# Allow outgoing SSH requests.$IPTABLES -A OUTPUT -m state --state NEW -p tcp --dport 22 -j ACCEPT# Allow outgoing FTP requests. Unencrypted, use with care.$IPTABLES -A OUTPUT -m state --state NEW -p tcp --dport 21 -j ACCEPT# Allow outgoing NNTP requests. Unencrypted, use with care.# $IPTABLES -A OUTPUT -m state --state NEW -p tcp --dport 119 -j ACCEPT# Allow outgoing NTP requests. Unencrypted, use with care.# $IPTABLES -A OUTPUT -m state --state NEW -p udp --dport 123 -j ACCEPT# Allow outgoing IRC requests. Unencrypted, use with care.# Note: This usually needs the ip_conntrack_irc kernel module.# $IPTABLES -A OUTPUT -m state --state NEW -p tcp --dport 6667 -j ACCEPT# Allow outgoing requests to various proxies. Unencrypted, use with care.# $IPTABLES -A OUTPUT -m state --state NEW -p tcp --dport 8080 -j ACCEPT# $IPTABLES -A OUTPUT -m state --state NEW -p tcp --dport 8090 -j ACCEPT# Allow outgoing DHCP requests. Unencrypted, use with care.# TODO: This is completely untested, I have no idea whether it works!# TODO: I think this can be tightened a bit more.$IPTABLES -A OUTPUT -m state --state NEW -p udp --sport 67:68 --dport 67:68 -j ACCEPT# Allow outgoing CVS requests. Unencrypted, use with care.# $IPTABLES -A OUTPUT -m state --state NEW -p tcp --dport 2401 -j ACCEPT# Allow outgoing MySQL requests. Unencrypted, use with care.# $IPTABLES -A OUTPUT -m state --state NEW -p tcp --dport 3306 -j ACCEPT# Allow outgoing SVN requests. Unencrypted, use with care.# $IPTABLES -A OUTPUT -m state --state NEW -p tcp --dport 3690 -j ACCEPT# Allow outgoing PLESK requests. Unencrypted, use with care.# $IPTABLES -A OUTPUT -m state --state NEW -p tcp --dport 8443 -j ACCEPT# Allow outgoing Tor (http://tor.eff.org) requests.# Note: Do _not_ use unencrypted protocols over Tor (sniffing is possible)!# $IPTABLES -A OUTPUT -m state --state NEW -p tcp --dport 9001 -j ACCEPT# $IPTABLES -A OUTPUT -m state --state NEW -p tcp --dport 9002 -j ACCEPT# $IPTABLES -A OUTPUT -m state --state NEW -p tcp --dport 9030 -j ACCEPT# $IPTABLES -A OUTPUT -m state --state NEW -p tcp --dport 9031 -j ACCEPT# $IPTABLES -A OUTPUT -m state --state NEW -p tcp --dport 9090 -j ACCEPT# $IPTABLES -A OUTPUT -m state --state NEW -p tcp --dport 9091 -j ACCEPT# Allow outgoing OpenVPN requests.$IPTABLES -A OUTPUT -m state --state NEW -p udp --dport 1194 -j ACCEPT# TODO: ICQ, MSN, GTalk, Skype, Yahoo, etc...# Selectively allow certain inbound connections, block the rest.#------------------------------------------------------------------------------# Allow incoming DNS requests.$IPTABLES -A INPUT -m state --state NEW -p udp --dport 53 -j ACCEPT$IPTABLES -A INPUT -m state --state NEW -p tcp --dport 53 -j ACCEPT# Allow incoming HTTP requests.$IPTABLES -A INPUT -m state --state NEW -p tcp --dport 80 -j ACCEPT# Allow incoming HTTPS requests.$IPTABLES -A INPUT -m state --state NEW -p tcp --dport 443 -j ACCEPT# Allow incoming POP3 requests.$IPTABLES -A INPUT -m state --state NEW -p tcp --dport 110 -j ACCEPT# Allow incoming IMAP4 requests.$IPTABLES -A INPUT -m state --state NEW -p tcp --dport 143 -j ACCEPT# Allow incoming POP3S requests.$IPTABLES -A INPUT -m state --state NEW -p tcp --dport 995 -j ACCEPT# Allow incoming SMTP requests.$IPTABLES -A INPUT -m state --state NEW -p tcp --dport 25 -j ACCEPT# Allow incoming SSH requests.$IPTABLES -A INPUT -m state --state NEW -p tcp --dport 22 -j ACCEPT# Allow incoming FTP requests.$IPTABLES -A INPUT -m state --state NEW -p tcp --dport 21 -j ACCEPT# Allow incoming NNTP requests.# $IPTABLES -A INPUT -m state --state NEW -p tcp --dport 119 -j ACCEPT# Allow incoming MySQL requests.# $IPTABLES -A INPUT -m state --state NEW -p tcp --dport 3306 -j ACCEPT# Allow incoming PLESK requests.# $IPTABLES -A INPUT -m state --state NEW -p tcp --dport 8843 -j ACCEPT# Allow incoming BitTorrent requests.