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Showing posts from January, 2013

DDoS Protection tool

mod_evasive module: We are going to install mod_evasive to help protect our server from low end ddos attacks. mod_evasive is an evasive maneuvers module for Apache to provide evasive action in the event of an HTTP DoS or DDoS attack or brute force attack. It is also designed to be a detection and network management tool, and can be easily configured to talk to ipchains, firewalls, routers, and etc… Detection is performed by creating an internal dynamic hash table of IP Addresses and URIs, and denying any single IP address from any of the following: Requesting the same page more than a few times per second Making more than 50 concurrent requests on the same child per second Making any requests while temporarily blacklisted (on a blocking list) Installation: root@serv [~]# cd /usr/local/src root@serv [~]# wget http://www.zdziarski.com/blog/wp-content/uploads/2010/02/mod_evasive_1.10.1.tar.gz root@serv [~]# tar -xzvf mod_evasive_1.10.1.tar.gz root@serv [~]# cd mod_

Practical Usages of Mysqladmin Commands

Here are some command that should know to manage the mysql environment: To check whether MySQL Server is up and running: root@server [~] # mysqladmin ping mysqld is alive root@server [~]# To find out what version of MySQL is running? root@server [~] # mysqladmin version mysqladmin  Ver 8.41 Distrib 5.0.96, for unknown-linux-gnu on x86_64 Copyright (c) 2000, 2011, Oracle and/or its affiliates. All rights reserved. Oracle is a registered trademark of Oracle Corporation and/or its affiliates. Other names may be trademarks of their respective owners. Server version          5.0.96-community Protocol version        10 Connection              Localhost via UNIX socket UNIX socket             /var/lib/mysql/mysql.sock Uptime:                 6 hours 1 min 59 sec Threads: 12  Questions: 17822637  Slow queries: 2497  Opens: 126271  Flush tables: 1  Open tables: 1024  Queries per second avg: 820.601 root@server [~]# To know the current status of MySQL server? root@

DKIM and SPF in cPanel

Install DKIM and SPF in cPanel: Both the DKIM and SPF authentication functions require the server to be a DNS server for the domain name. DKIM: DKIM helps verify the sender and integrity of a message. It allows an email system to prove that a message was not altered during transit (meaning it is not forged), and that the message came from the specified domain.  SPF: SPF attempts to prevent spammers from sending email while forging your domain’s name as the sender (spoofing). This authentication function works by adding IP addresses to a list, specifying computers that are authorized to send mail from your domain(s). It verifies that messages sent from your domain(s) are coming from the listed server, reducing the amount of backscatter you receive. Command to enable DKIM and SPF for cPanel user. # /usr/local/cpanel/bin/dkim_keys_install cPanelusername # /usr/local/cpanel/bin/spf_installer cPanelusername If you would like to enalbe DKIM and SPF for All the use

How to change Network Interface Speed

Changing Network Interface Speed: You can check the N/W interface speed through "ethtool"command. # ethtool - Display or change ethernet card settings [root@localhost ~] # ethtool eth0 Settings for eth0:         Supported ports: [ TP MII ]         Supported link modes:   10baseT/Half 10baseT/Full                             100baseT/Half 100baseT/Full                                  1000baseT/Half 1000baseT/Full         Supports auto-negotiation: Yes         Advertised link modes:  10baseT/Half 10baseT/Full                                  100baseT/Half 100baseT/Full                                  1000baseT/Half 1000baseT/Full         Advertised auto-negotiation: Yes         Speed: 10Mb/s         Duplex: Half         Port: MII         PHYAD: 0         Transceiver: internal         Auto-negotiation: on         Supports Wake-on: pumbg         Wake-on: g         Current message level: 0x00000033 (51)         Link detected: yes The result shoul

Regarding vpn error

hi friends, i have installed openvpn in centos server.i got all the details from the client including client.key .when i tried to communicate the client it shows the following error Fri Jan 4 15:42:22 2013: IMPORTANT: OpenVPN's default port number is now 1194, based on an official port number assignment by IANA. OpenVPN 2.0-beta16 and earlier used 5000 as the default port. Fri Jan 4 15:42:22 2013: WARNING: Make sure you understand the semantics of --tls-remote before using it (see the man page). Fri Jan 4 15:42:22 2013: NOTE: the current --script-security setting may allow this configuration to call user-defined scripts Fri Jan 4 15:42:22 2013: WARNING: file 'gatekeeper-udp-1194.p12' is group or others accessible Fri Jan 4 15:42:22 2013: WARNING: file 'gatekeeper-udp-1194-tls.key' is group or others accessible Fri Jan 4 15:42:22 2013: Control Channel Authentication: using 'gatekeeper-udp-1194-tls.key' as a OpenVPN static key file Fri Jan 4

Seek time and Latency with respect to disk I/O.

Definition of Seek time and Latency in Hard Disk: Seek Time - As soon as the read/write command is received by the disk unit,the read/write heads are 1st positioned on to the specified track/cylinder number.The time required to position the read/write head over the desired track is called seek time. Latency - Once the heads are positioned on the desired track,the head on the specified surface is activated.Since the disk is continuously rotating,the head should wait for the specified sector to come under it.This rotational waiting time required to spin the desired sector under the head is called latency(Rotational Delay Time).