# rules.before
#
# Rules that should be run before the ufw command line added rules. Custom
# rules should be added to one of these chains:
# ufw-before-input
# ufw-before-output
# ufw-before-forward
#
# Don't delete these required lines, otherwise there will be errors
*filter
:ufw-before-input - [0:0]
:ufw-before-output - [0:0]
:ufw-before-forward - [0:0]
:ufw-not-local - [0:0]
# End required lines
# allow all on loopback
-A ufw-before-input -i lo -j ACCEPT
-A ufw-before-output -o lo -j ACCEPT
# 3.6.3 Ensure loopback traffic is configured (Scored)
-A ufw-before-input -s 127.0.0.0/8 -j DROP
# quickly process packets for which we already have a connection
-A ufw-before-input -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT
-A ufw-before-output -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT
-A ufw-before-forward -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT
# drop INVALID packets (logs these in loglevel medium and higher)
-A ufw-before-input -m conntrack --ctstate INVALID -j ufw-logging-deny
-A ufw-before-input -m conntrack --ctstate INVALID -j DROP
# ok icmp codes for INPUT
-A ufw-before-input -p icmp --icmp-type destination-unreachable -j ACCEPT
-A ufw-before-input -p icmp --icmp-type source-quench -j ACCEPT
-A ufw-before-input -p icmp --icmp-type time-exceeded -j ACCEPT
-A ufw-before-input -p icmp --icmp-type parameter-problem -j ACCEPT
-A ufw-before-input -p icmp --icmp-type echo-request -j ACCEPT
# ok icmp code for FORWARD
-A ufw-before-forward -p icmp --icmp-type destination-unreachable -j ACCEPT
-A ufw-before-forward -p icmp --icmp-type source-quench -j ACCEPT
-A ufw-before-forward -p icmp --icmp-type time-exceeded -j ACCEPT
-A ufw-before-forward -p icmp --icmp-type parameter-problem -j ACCEPT
-A ufw-before-forward -p icmp --icmp-type echo-request -j ACCEPT
# allow dhcp client to work
-A ufw-before-input -p udp --sport 67 --dport 68 -j ACCEPT
#
# ufw-not-local
#
-A ufw-before-input -j ufw-not-local
# if LOCAL, RETURN
-A ufw-not-local -m addrtype --dst-type LOCAL -j RETURN
# if MULTICAST, RETURN
-A ufw-not-local -m addrtype --dst-type MULTICAST -j RETURN
# if BROADCAST, RETURN
-A ufw-not-local -m addrtype --dst-type BROADCAST -j RETURN
# all other non-local packets are dropped
-A ufw-not-local -m limit --limit 3/min --limit-burst 10 -j ufw-logging-deny
-A ufw-not-local -j DROP
# allow MULTICAST mDNS for service discovery (be sure the MULTICAST line above
# is uncommented)
-A ufw-before-input -p udp -d 224.0.0.251 --dport 5353 -j ACCEPT
# allow MULTICAST UPnP for service discovery (be sure the MULTICAST line above
# is uncommented)
-A ufw-before-input -p udp -d 239.255.255.250 --dport 1900 -j ACCEPT
# don't delete the 'COMMIT' line or these rules won't be processed
COMMIT
in /etc/ufw/sysctl.conf:
# Configuration file for setting network variables. Please note these settings
# override /etc/sysctl.conf. If you prefer to use /etc/sysctl.conf, please
# adjust IPT_SYSCTL in /etc/default/ufw.
#
# Uncomment this to allow this host to route packets between interfaces
#net/ipv4/ip_forward=1
#net/ipv6/conf/default/forwarding=1
#net/ipv6/conf/all/forwarding=1
# Turn on Source Address Verification in all interfaces to prevent some
# spoofing attacks
net/ipv4/conf/default/rp_filter=1
net/ipv4/conf/all/rp_filter=1
# Do not accept IP source route packets (we are not a router)
net/ipv4/conf/default/accept_source_route=0
net/ipv4/conf/all/accept_source_route=0
net/ipv6/conf/default/accept_source_route=0
net/ipv6/conf/all/accept_source_route=0
# Disable ICMP redirects. ICMP redirects are rarely used but can be used in
# MITM (man-in-the-middle) attacks. Disabling ICMP may disrupt legitimate
# traffic to those sites.
net/ipv4/conf/default/accept_redirects=0
net/ipv4/conf/all/accept_redirects=0
net/ipv6/conf/default/accept_redirects=0
net/ipv6/conf/all/accept_redirects=0
# Ignore bogus ICMP errors
net/ipv4/icmp_echo_ignore_broadcasts=1
net/ipv4/icmp_ignore_bogus_error_responses=1
net/ipv4/icmp_echo_ignore_all=0
# Don't log Martian Packets (impossible packets)
net/ipv4/conf/default/log_martians=1
net/ipv4/conf/all/log_martians=1
# Change to '1' to enable TCP/IP SYN cookies This disables TCP Window Scaling
# (http://lkml.org/lkml/2008/2/5/167)
net/ipv4/tcp_syncookies=1
#net/ipv4/tcp_fin_timeout=30
#net/ipv4/tcp_keepalive_intvl=1800
# normally allowing tcp_sack is ok, but if going through OpenBSD 3.8 RELEASE or
# earlier pf firewall, should set this to 0
net/ipv4/tcp_sack=1
# Uncomment this to turn off ipv6 autoconfiguration
#net/ipv6/conf/default/autoconf=0
#net/ipv6/conf/all/autoconf=0
# Uncomment this to enable ipv6 privacy addressing
#net/ipv6/conf/default/use_tempaddr=2
#net/ipv6/conf/all/use_tempaddr=2
This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.
in
/etc/ufw/ufw.conf
:in
/etc/ufw/user.rules
:in
/etc/ufw/before.rules
:in
/etc/ufw/sysctl.conf
: