Linux - SecurityThis forum is for all security related questions.
Questions, tips, system compromises, firewalls, etc. are all included here.
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.
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.
Introduction to Linux - A Hands on Guide
This guide was created as an overview of the Linux Operating System, geared toward new users as an exploration tour and getting started guide, with exercises at the end of each chapter.
For more advanced trainees it can be a desktop reference, and a collection of the base knowledge needed to proceed with system and network administration. This book contains many real life examples derived from the author's experience as a Linux system and network administrator, trainer and consultant. They hope these examples will help you to get a better understanding of the Linux system and that you feel encouraged to try out things on your own.
Click Here to receive this Complete Guide absolutely free.
In my LAN, the host with IP 188.8.131.52 has some Winblows virus that is generating outgoing traffic on my network. I donṫ know where this PC is, since it wasnṫ given a DHCP name. I issued the following three commands but they didnṫ stop the traffic:
iptables -I INPUT -s 192.168.0.113 -j DROP
iptables -I OUTPUT -s 192.168.0.113 -j DROP
iptables -I FORWARD -s 192.168.0.113 -j DROP
I wanna try blocking it by its MAC address. How do I do that?
do this (make sure you have the ipt_mac module loaded, too)
iptables -A INPUT -p ALL -m mac --mac-source <insert MAC of offending computer here> -j DROP
this matches the source of the packet to a given MAC, then drops it if it matches (might be obvious, but just in case ). you can also put this in the FORWARD/OUTPUT chain to stop stuff (depends on your iptables).
it's definitely odd that that rule doesn't work. i have a rule like that to match the MAC of my remote computer and it works fine. here's are some rules (verbatim; except for changed MAC) i have in my iptables:
# allows DHCPACK for setup of w-lan
$IPTABLES -A INPUT -p UDP -i wlan0 --dport 67 --sport 68 -m mac --mac-source <remote MAC> -j ACCEPT
# allow ssh in from horatio
$IPTABLES -A INPUT -p TCP -i wlan0 --dport 22 -m mac --mac-source <remote MAC> -j ACCEPT
# only let established/related ssh connections to chimaera in from horatio
$IPTABLES -A INPUT -p TCP -i wlan0 -m state --state ESTABLISHED,RELATED -m mac --mac-source <remote MAC> -j ACCEPT
# allows w-lan valid outgoing through, but stops new/invalid connections through wlan0
$IPTABLES -A FORWARD -i ppp0 -o wlan0 -m state --state ESTABLISHED,RELATED -j ACCEPT
$IPTABLES -A FORWARD -i wlan0 -o ppp0 -m state ! --state INVALID -m mac --mac-source <remote MAC> -j ACCEPT
these rules all work on my router/firewall box. it's odd that the rule didn't work, but maybe it has something to do with the cisco stuff that tarballed has been talking about.