Linux - Security This forum is for all security related questions.
Questions, tips, system compromises, firewalls, etc. are all included here. |
Notices |
Welcome to LinuxQuestions.org, a friendly and active Linux Community.
You are currently viewing LQ as a guest. By joining our community you will have the ability to post topics, receive our newsletter, use the advanced search, subscribe to threads and access many other special features. Registration is quick, simple and absolutely free. Join our community today!
Note that registered members see fewer ads, and ContentLink is completely disabled once you log in.
Are you new to LinuxQuestions.org? Visit the following links:
Site Howto |
Site FAQ |
Sitemap |
Register Now
If you have any problems with the registration process or your account login, please contact us. If you need to reset your password, click here.
Having a problem logging in? Please visit this page to clear all LQ-related cookies.
Get a virtual cloud desktop with the Linux distro that you want in less than five minutes with Shells! With over 10 pre-installed distros to choose from, the worry-free installation life is here! Whether you are a digital nomad or just looking for flexibility, Shells can put your Linux machine on the device that you want to use.
Exclusive for LQ members, get up to 45% off per month. Click here for more info.
|
|
07-23-2007, 08:36 AM
|
#1
|
LQ Newbie
Registered: Jul 2007
Posts: 2
Rep:
|
iptables security
Hello friends ,
This is my first Thread in the LQ Blog. I want to ask one question regarding iptables.
what is the difference in using a very strong iptables firewall (like arno or other complex iptables scripts ) and using simple script like this one.
Suppose m using a public ip
iptables -P INPUT DROP
iptables -P FORWARD DROP
iptables --flush # Flush all rules, but keep policies
iptables --delete-chain
iptables -P FORWARD DROP
iptables -P INPUT DROP
iptables -A INPUT -i lo --source 127.0.0.1 --destination 127.0.0.1 -j ACCEPT
iptables -A INPUT -m state --state "ESTABLISHED,RELATED" -j ACCEPT
iptables -A INPUT -p icmp --icmp-type destination-unreachable -j ACCEPT
iptables -A INPUT -p icmp --icmp-type time-exceeded -j ACCEPT
iptables -A INPUT -p icmp --icmp-type echo-request -j ACCEPT
iptables -A INPUT -p icmp --icmp-type echo-reply -j ACCEPT
iptables -A INPUT -p tcp --dport ssh -j ACCEPT
iptables -A INPUT -p tcp --dport http -j ACCEPT
iptables -A INPUT -j LOG -m limit --limit 40/minute
iptables -A INPUT -j DROP
as in this script i am not opening any ports (except 80 and 22 ) for the outsiders, so m i totally protected by this script or else i have to use complex iptables scripts to protect from the hackers.
|
|
|
07-23-2007, 10:14 AM
|
#2
|
LQ Guru
Registered: Nov 2004
Location: San Jose, CA
Distribution: Debian, Arch
Posts: 8,507
Rep:
|
There's no such thing as "totally protected". But this will not permit inbound connections except to ports 80 and 22, thus protecting any other services from attack. You may want to consider DROPing packets with state INVALID somewhere in there as well.
|
|
|
07-24-2007, 12:52 PM
|
#3
|
Member
Registered: Apr 2006
Location: Sweden
Distribution: CentOS, RHEL, SourceMage, OpenBSD
Posts: 40
Rep:
|
There are also some other things you can do to prevent SYN floods and other kinds of attacks for example:
echo 1 >/proc/sys/net/ipv4/tcp_syncookies
echo 1 >/proc/sys/net/ipv4/conf/all/rp_filter
echo 1 >/proc/sys/net/ipv4/conf/all/log_martians
Also, you may want to consider filtering outgoing traffic too.
|
|
|
All times are GMT -5. The time now is 08:33 PM.
|
LinuxQuestions.org is looking for people interested in writing
Editorials, Articles, Reviews, and more. If you'd like to contribute
content, let us know.
|
Latest Threads
LQ News
|
|