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Full Discussion: Need help for iptables rules
Special Forums Cybersecurity Need help for iptables rules Post 302988595 by Thomas342 on Thursday 29th of December 2016 06:39:56 AM
Old 12-29-2016
Need help for iptables rules

Hello,

I did 2 scripts. The second one is, I hope, more secure.
What do you think?


Basic connection (no server, no router, no DHCP and the Ipv6 is disabled)

#######script one
####################

Code:
iptables -F
iptables -X -t filter
iptables -P INPUT DROP 
iptables -P FORWARD DROP 
iptables -P OUTPUT ACCEPT

#lo
iptables -A INPUT -i lo -j ACCEPT
iptables -A INPUT ! -i lo -d 127.0.0.0/8 -j REJECT
iptables -A OUTPUT -o lo -j ACCEPT

#CONNECTION
iptables -A INPUT -m state --state ESTABLISHED -j ACCEPT

#PING ACCEPTED AND OPENING PORTS THAT I NEED
iptables -A INPUT -p icmp --icmp-type echo-request -m conntrack --ctstate NEW -m limit --limit 1/s --limit-burst 1 -j ACCEPT
iptables -A INPUT -p tcp --dport xxxx -j ACCEPT
iptables -A INPUT -p udp --dport xxxx -j ACCEPT

#LOG
iptables -A INPUT -m limit --limit 5/min -j LOG --log-prefix "iptables denied: " --log-level 7
iptables -A FORWARD -j LOG



######SCRIPT 2 ### SCRIPT (MORE SECURE) #####
#######################
Code:
iptables -F
iptables -X -t filter
iptables -P INPUT -j DROP
iptables -P FORWARD DROP 
iptables -P OUTPUT -j DROP

modprobe ip-conntrack

#lo
iptables -A INPUT -i lo -j ACCEPT
iptables -A INPUT ! -i lo -d 127.0.0.0/8 -j REJECT
iptables -A OUTPUT -o lo -j ACCEPT

#connection
iptables -A INPUT -m state --state ESTABLISHED -j ACCEPT
iptables -A OUTPUT -m state ! --state INVALID -j ACCEPT

#PING ACCEPTED AND OPENING PORTS THAT I NEED
iptables -A INPUT -p icmp --icmp-type echo-request -m conntrack --ctstate NEW -m limit --limit 1/s --limit-burst 1 -j ACCEPT
iptables -A INPUT -d 0.0.0.0/0 -p tcp --sport xxxx -m state --state ESTABLISHED -j ACCEPT (I don't know if I must add 0.0.0.0/0 or 192.168.0.0/24)
iptables -A INPUT -m limit --limit 7/s -j LOG

#LOG
iptables -A OUTPUT -m limit --limit 7/s -j LOG
iptables -A FORWARD -m limit --limit 7/s -j LOG


Thanks in advance
 

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IPTABLES-APPLY(8)						  iptables 1.6.1						 IPTABLES-APPLY(8)

NAME
iptables-apply - a safer way to update iptables remotely SYNOPSIS
iptables-apply [-hV] [-t timeout] [-w savefile] {[rulesfile]|-c [runcmd]} DESCRIPTION
iptables-apply will try to apply a new rulesfile (as output by iptables-save, read by iptables-restore) or run a command to configure iptables and then prompt the user whether the changes are okay. If the new iptables rules cut the existing connection, the user will not be able to answer affirmatively. In this case, the script rolls back to the previous working iptables rules after the timeout expires. Successfully applied rules can also be written to savefile and later used to roll back to this state. This can be used to implement a store last good configuration mechanism when experimenting with an iptables setup script: iptables-apply -w /etc/network/iptables.up.rules -c /etc/network/iptables.up.run When called as ip6tables-apply, the script will use ip6tables-save/-restore and IPv6 default values instead. Default value for rulesfile is '/etc/network/iptables.up.rules'. OPTIONS
-t seconds, --timeout seconds Sets the timeout in seconds after which the script will roll back to the previous ruleset (default: 10). -w savefile, --write savefile Specify the savefile where successfully applied rules will be written to (default if empty string is given: /etc/network/iptables.up.rules). -c runcmd, --command runcmd Run command runcmd to configure iptables instead of applying a rulesfile (default: /etc/network/iptables.up.run). -h, --help Display usage information. -V, --version Display version information. SEE ALSO
iptables-restore(8), iptables-save(8), iptables(8). LEGALESE
Original iptables-apply - Copyright 2006 Martin F. Krafft <madduck@madduck.net>. Version 1.1 - Copyright 2010 GW <gw.2010@tnode.com or http://gw.tnode.com/>. This manual page was written by Martin F. Krafft <madduck@madduck.net> and extended by GW <gw.2010@tnode.com or http://gw.tnode.com/>. Permission is granted to copy, distribute and/or modify this document under the terms of the Artistic License 2.0. iptables 1.6.1 IPTABLES-APPLY(8)
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