Admins eHow SysAdmin Tips & Tricks

September 5, 2011

IPTables packet traverse map

Filed under: CentOS,Debian,General,linux,Security — Tags: , , , , , — admin @ 7:23 am

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April 27, 2011

Block BitTorrent traffic on your Linux firewall using iptables

Filed under: Debian,linux,Security — Tags: , , , , , — admin @ 7:25 pm

The following script will block and log un-encrypted BitTorrent & DHT traffic on your Linux firewall.
I have personally tested it on debian 5 lenny , but I am almost sure it should work pretty well on any new Linux distros.

iptables -N LOGDROP > /dev/null 2> /dev/null 
iptables -F LOGDROP 
iptables -A LOGDROP -j LOG --log-prefix "LOGDROP " 
iptables -A LOGDROP -j DROP

#Torrent
iptables -A FORWARD -m string --algo bm --string "BitTorrent" -j LOGDROP 
iptables -A FORWARD -m string --algo bm --string "BitTorrent protocol" -j LOGDROP
iptables -A FORWARD -m string --algo bm --string "peer_id=" -j LOGDROP
iptables -A FORWARD -m string --algo bm --string ".torrent" -j LOGDROP
iptables -A FORWARD -m string --algo bm --string "announce.php?passkey=" -j LOGDROP 
iptables -A FORWARD -m string --algo bm --string "torrent" -j LOGDROP
iptables -A FORWARD -m string --algo bm --string "announce" -j LOGDROP
iptables -A FORWARD -m string --algo bm --string "info_hash" -j LOGDROP 

# DHT keyword
iptables -A FORWARD -m string --string "get_peers" --algo bm -j LOGDROP
iptables -A FORWARD -m string --string "announce_peer" --algo bm -j LOGDROP
iptables -A FORWARD -m string --string "find_node" --algo bm -j LOGDROP

August 27, 2009

How to clear all iptables rules

Filed under: CentOS,Debian,General,Security — Tags: , , , — admin @ 2:08 pm

In order to flush all iptables rules , Run the following commands :

iptables -F
iptables -X
iptables -t nat -F
iptables -t nat -X
iptables -t mangle -F
iptables -t mangle -X
iptables -P INPUT ACCEPT
iptables -P FORWARD ACCEPT
iptables -P OUTPUT ACCEPT

June 6, 2009

iptables v1.3.5: can’t initialize iptables table `filter’: iptables who? (do you need to insmod?)

Filed under: XEN — Tags: , , — admin @ 8:10 am

Typically this occurs when a kernel update occurred on the node. Run this on the server node and then restart the VM having trouble.

/script/fixxenkernel

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