Protect the server from Flood attacks , Using the property Port Flood Protection In firewall CSF . After doing the necessary settings will be able to determine the number of allowed connections Same time for each IP tries to connect to the server.

So How to Make a flood attack ?
Logically flood attacks are two ways :
first through a specific communication
the second through multiple connections each connection of these connections connect with the provider
Requirements

1. Installing firewall CSF last version
2. Enabled IPT and works well
3. Model IPT_Recent special for IPT

Application

Through edited the configuration file special for CSF it is located in the following path:

root@server:$ nano /etc/csf/csf.conf

We pressing CTRL + W and look for PORTFLOOD we will find the line as follows default :

PORTFLOOD = " "

put inside ” ” Settings that we want ,as in the following example:

PORTFLOOD = "80;tcp;20;10"

80 is the port , TCP is the protocol , 20 is the number of connections allowed at the same time , 10 is time of pause temporarily after the 10 seconds is allowed IP make new contacts

Important note: ipt_recent can count 20 Packets for each Title , So you can change the number of connections from 1 to 20 only

Is there a possibility of adding more than one port ?yes be as follows (Just an example) :

PORTFLOOD = "22;tcp;10;200,21;tcp;15;100,80;tcp;20;5"

Note that when we add a new port we put a comma (,)

In the previous example you choose more than one port are 22, 21 and 80 And you can add more and you can change the number of connections and also change the protocol type, for example, from TCP to UDP after the completion of the edited we save the file : CTRL + X, Y, and then Enter button.

Finally, do not forget to restart CSF with the following command:

root@server:$ csf -r

Thank You ,,

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If you use Memcached server to store application data, you may want to invalidate it once you deploy a new version to avoid corruption or weird results… In this article, I’ll show you How do I flush the entire contents of a Memcached server ?

Using telnet command

I often use telnet to flush the entire contents of Memcached server, type the following command

# telnet localhost 11211

Output

Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.
flush_all
OK
quit
Connection to localhost closed by foreign host.

Where
– localhost: Memcached server instance
– 11211: Memcached server port

Using netcat command

# echo "flush_all" | nc localhost 11211

By default, nc (or netcat) creates a TCP socket either in listening mode (server socket) or a socket that is used in order to connect to a server (client mode). Actually, netcat does not care whether the socket is meant to be a server or a client. All it does is to take the data from stdin and transfer it to the other end across the network.

Restart Memcached Server

Login as root and type the following command

# /etc/init.d/memcached restart

Restarting your application is not ideal however, you will lose anything cached in memory, cause delays to users trying to access your site, that sort of thing.

Using PHP script

Create php file with the following content

# vi flush_memcached.php
$memcache = new Memcache;
$memcache->connect('localhost', 11211);
$memcache->flush();

To execute this script, type the following command

# php flush_memcached.php

The post How To Flush The Entire Contents Of Memcache Server appeared first on lifeLinux: Linux Tips, Hacks, Tutorials, Ebooks.