If you are not able to connect to FTP data port using passive-mode and getting the connection error as:

“FTP Connection Error:

Error loading directory”

————————————————————–

“Server failed to connect data port

Error loading directory…”

————————————————————-

Then there is possibility that a port range is not open in the firewall to match the port range used by the FTP service.

There are two options to fix this:

1) Use active-mode FTP instead of passive. This is normally selectable in the FTP client. In the command-line FTP client, you can simply type “passive” to toggle passive/active mode.

2) Configure a port range for passive-mode FTP in the FTP service configuration, and configure the server’s firewall to allow the connection on them.

If you are using Pure-FTPd, which is the default, you can define the passive-mode port range by editing /etc/pure-ftpd.conf and uncommenting the following directive:

Code:

# Port range for passive connections replies.

# PassivePortRange          30000 50000

Once you have removed the hash mark (#) from the line starting with

“PassivePortRange”, restart Pure-FTPd and edit your firewall configuration to allow traffic on the same port range as mentioned below :

Assuming that your eth0 network interface has public ip (119.54.1.20). FTP uses both port 21 and 20 (port 21 for the command port and port 20 for the data). So following iptables rules take care of both ports (add rules to your iptables based shell script):

1)  Add support for FTP connection tracking via enabling the two iptable modules  as given below:

First login as the root user.

Next type the following command to load two iptables modules:

# modprobe ip_conntrack

# modprobe ip_conntrack_ftp

2)  Now add following iptable rules for incoming request on port 21 (open port 21) to your script:

# iptables -A INPUT -p tcp -s 0/0 --sport 30000:50000 -d 119.54.1.20 --dport 21 –m state --state NEW,ESTABLISHED -j ACCEPT

# iptables -A OUTPUT -p tcp -s 119.54.1.20 --sport 21 -d 0/0 --dport 30000:50000 –m state --state ESTABLISHED -j ACCEPT

3)  Now add following iptable rules for allowing the passive post range to your script:

# iptables -A INPUT -p tcp -s 0/0 --sport 30000:50000 -d 119.54.1.20 --dport 30000:50000 -m state --state ESTABLISHED,RELATED -j ACCEPT

# iptables -A OUTPUT -p tcp -s 119.54.1.20 --sport 30000:50000 -d 0/0 --dport 30000:50000 -m state --state ESTABLISHED -j ACCEPT

4)  Now add following iptable rules for allowing the FTP data Port(20) and passive post range to your script:

# iptables -A OUTPUT -p tcp -s 119.54.1.20 --sport 20 -d 0/0 --dport 30000:50000 –m state --state ESTABLISHED,RELATED -j ACCEPT

# iptables -A INPUT -p tcp -s 0/0 --sport 30000:50000 119.54.1.20 --dport 20 -m state --state ESTABLISHED -j ACCEPT

Now save the iptables rules as below:

# service iptables save

Now try accessing the FTP. It should be working for you.

The post Resolve Passive FTP Data Port connection error first appeared on Round Robin DNS Information and Services.

How to add targeted Host in Nagios?

1) This syntax example shows to add a target “node01.rrdns.com [10.10.0.201]”.

[root@master ~]#chgrp nagios /etc/nagios/servers

[root@master ~]#chmod 750 /etc/nagios/servers

[root@master ~]#vi /etc/nagios/servers/node01.cfg

# create new

define host{
use linux-server
host_name node01
alias node01
address 10.10.0.201
}
define service{
use generic-service
host_name node01
service_description PING
check_command check_ping!100.0,20%!500.0,60%
}

[root@master ~]#/etc/rc.d/init.d/nagios restart
Running configuration check…done.
Stopping nagios: .done.
Starting nagios: done.

2) You can access Nagios admin site and confirm the target hosts added or not.

The post How to add targeted Host in Nagios first appeared on Round Robin DNS Information and Services.

We are happy to announce our strategic partnership with Servers.co.in for providing Round Robin Clusters and Servers in India for our ever-increasing Asian client base. Servers.co.in providers great and affordable servers with top quality network and 24×7 great localized support. Our managed clusters are hosted in their state of art facilities and some of our clients have already started utilizing our Asian presence for CDN and other advanced hosting needs.

They are currently offering 25% discount on all their hosting plans and will offer 30% discount on custom clusters off the first invoice. All our offerings like pro blogging clusters, CDN servers, reverse cache proxies, clustered hosting and advanced web hosting are available in Asia with the help of our partner Servers.co.in. Please feel free to send in a query to sales@servers.co.in if you are interested in any of our services in Asia.

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Database is nothing but the collection of data which will be used for any website.
Let’s take an example over here, suppose a computer having some files saved name as rrdns.doc, server.doc, host.doc so on.
While finding a particular file name which includes business proposal data which has been made some time ago say for RRDNS Hosting So which file should you open?
One way is to sequentially check each and every single file starting from “rrdns.doc” till you gets the right data but this will bring us a highly inefficient method to getting a right file.
There are multiple database software’s that can help to locate the correct file without to manually open every single file sequentially like MySQL.
MySQL is database software which is just program to lets you store and retrieve that data as efficiently as possible.
MySQL is easy to use, powerful, secure and scalable. Because of its small size and speed, it is the ideal database solution for Web sites. It has a solid data security layer which protects data from intruders.
MySQL is Specialised database software and Open Source Database Management System that mean it is possible to use and modify the software.
MySQL databases are commonly used by programs that run on websites.it is what which holds all of website database tables, Queries.
It’s used with web applications and closely to the popularity of PHP
RRDNS servers has been thoroughly tested to prevent memory leaks which having MySQL databases.
RRDNS Clients can be access their MySQL database remotely from RRDNS server through standard TCP/IP sockets using graphical application such as HeidiSQL.
All web hosting companies generally support associated with Unix/Linux base server, If you want your own page and want MYSQL/PHP support check out http://www.rrdnshosting.com/.
If we want to build a website with bunch of information that the visitors cannot quickly find OR Visitors want to impart information to you, both of these problems can be solved by building a database for the website.
With the help of MySQL databases we can arrange our website information in a systematic format.
Database software’s have many methods for storing, retrieve and organising the stored data.
How to check and select database from command line?
To login database server.

# mysql -h localhost -p -u databaseusername
# mysql> SHOW databases; To check the available databases.
# mysql> SELECT database(); To get currunt database name.

How to Create Database from command line?

mysql> create database databasename;
mysql> grant usage on *.* to databaseusername@localhost identified by 'Databasepassword';
mysql> grant all privileges on databasename.* to databaseuser@localhost ;
mysql> grant CREATE,INSERT,DELETE,UPDATE,SELECT on pauldb.* to databaseusername@localhost;
mysql> set password for databaseuser = password('mysecretpassword');

How To Enable Query Cache?

Before enable query cache it is enabled or not using following command.

mysql> show variables like 'have_query_cache';

If the result is 0 like in the following example, then the query cache is not enabled:
To Install Query Cache On the Server:

mysql> SET GLOBAL query_cache_size = 16777216;

To verify if the changes have been done or not.

mysql> SHOW VARIABLES LIKE ‘query_cache_size’;
To Enable Query cache via /etc/my.cnf

Vi /etc/my.cnf

Insert following Values into the file

query_cache_size = 268435456
query_cache_type=1
query_cache_limit=1048576

To resolve mysqldump: Got error: 1045: Access denied for user Error.

1. Check that whether you have created the proper MySQL user and gave them the required permission. You can check the user permission by following command.

# SHOW GRANTS FOR 'user'@'localhost';

OR

#SHOW GRANTS FOR 'user'@'192.168.1.10';

2. If the permissions are not proper, you might think of providing it properly by

# GRANT ALL ON database.* TO 'user'@'localhost' identified by 'password';

3. Check whether you are including the host properly in case of remote MySQL connections.

# mysql -h host -u user -p database

3. Finally, if you have created user and didn’t restarted your MySQL server or ran following command, your MySQL user permissions will not take effect in-spite of creating them. (Ps. This was the issue I was having.)

#FLUSH PRIVILEGES

Removing blocked IP addresses manually from cPHulk’s database.

# mysql> use cphulkd;
# mysql> SELECT * FROM brutes WHERE `IP`=’xxx.xxx.xxx.xxx’;
# mysql> DELETE FROM brutes WHERE `IP`=’xxx.xxx.xxx.xxx’;
# mysql>quit

How to enable MySQL query logs

To enable the query log put following entry into the /etc/my.cnf file under [mysqld] section.

log = path to query.log
general_log=1

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Apache server, is a simply a public-domain open source Web Server developed by a loosely-knit group of programmers.

==About apache Web Server==

The first version of Apache, based on the NCSA(National Center for Supercomputing Applications) httpd Web server. Basically it was developed in 1995 and usually it uses on linux operating system.The original version of this server was written for UNIX, but there are now versions that run under OS/2, Windows/Linux and other platforms. Programmer “Brian Behlendorf” is the founder of Apache Web Server born March 30, 1973.

==Apache Server Versions==

Since its initial launch the web server has undergone a number of improvements, which led to the release of several versions. Below are the Apache Server versions along with their disscription.

-Apache 1.3- boasts a great deal of improvements over 1.2, the most noteworthy of them being – useful configurable files, Windows and Novell NetWare support, DSO support, APXS tool and others.

-Apache 2.0-differs from the previous versions by the much re-written code, which has considerably simplified its configuration and boosted its efficiency. It supports Ipv6, Unix threading, other protocols such as mod_echo. This version also offers a new compilation system and multi-language error messaging.

-Apache 2.2- came out in 2006 and offers new and more flexible modules for user authentication and proxy caching, support for files exceeding 2 GB, as well as SQL support.

==Advantage of Apache Server==

“Apache is…much faster serving static resources” as that’s highly qualitative.Apache is a popular open-source web server and has been the most popular open source web server on the internet for the last few years. With Apache, you can create VirtualHosts on your main server that will accept requests from designated servers and route them to the correct ports. These VirtualHosts can be defined in the configuration file, which is basically where most of the configuration for Apache is done.web server is a system that stores information and delivers, or “serves,” this data when needed. Every website on the Internet resides on a web server. When a user access website, server sends the data that is displayed on the screen.

==Apache Installation and Server configuration==

You can use below commands to install Apache on linux. You need to upload files at /var/www/html under RHEL / CentOS / Fedora Linux operating system. You need to configure and use Apache as per the requirement. /etc/httpd/conf/httpd.conf (RHEL/Cent OS/Fedora Core Linux) or /etc/apache2/httpd.conf (Debian / Ubuntu Linux) is the location of apache configuration file.

# yum install httpd
# chkconfig httpd on
# /etc/init.d/httpd start

The post Apache Server first appeared on Round Robin DNS Information and Services.

Domain management using cPanel is very easy.  Domain section allows you to manage your subdomains, addon domains and parked domains. Additionally you can set the redirects for your URL’s. Buying domain name transfer and domain ID protection becomes easy with Domain section of cPanel.

Domain management using cPanel

Through this section you can change the DNS settings of your domain as well..

Subdomains – Through this feature you can add subdomains for your primary, parked and addon domains.

Domain management-Subdomain

Addon domains – Through this feature you can add addon domains to your account.

Parked domains – Using this feature you can add parked domains to your account.

Redirects – Using this tool you can set a Temporary or a Permanent redirect for your web site to a separate one or from one file to another. You can also set a wild card redirect for all the files under a directory.

Domain management-redirect

Domain Transfer – If you have a domain name with top level domain extensions like .com, .net, .org, .info, .biz, .us, .co.uk, .org.uk and you wish to manage your domain more conveniently together with your hosting account, you can transfer your domain name to RRDNShosting.

Register New Domain – If you need a new domain name for your account, you can register one through RRDNShosting. Domain names with the following extensions can be registered – .com, .net, .org, .info, .biz, .us, .co.uk, .org.uk, .eu, .ca, .me, .tel, .mobi.

Domain ID Protect – Protect your privacy by hiding the WHOIS info for your domain name. With a Domain ID Protect you can hide your name and organization, living address, phone, email address, etc, which will be otherwise visible through public Domain Whois services.

Domain Manager – Manage your domain DNS and WHOIS information.

Primary Domain Change – You can change the primary domain name for your account to another one.

Advanced DNS Zone Editor – This tool gives you advanced options when editing your DNS zone.

Simple DNS Zone Editor – A simpler but efficient tool to manage your DNS zone.

The post Domain management using cPanel first appeared on Round Robin DNS Information and Services.

In order to run a PHP site, the server must interpret the PHP code and generate a page most probably in HTML format that should be easily readable by the browser, when visitors access the website.
A PHP handler actually loads the libraries so that they can be used for interpretation of PHP code.
There are multiple different handlers that can be used for loading PHP with an Apache server :-

– CGI
– DSO
– suPHP
-FastCGI.

Each handler delivers the libraries through different files and implementations. Each file and implementation affects Apache’s performance, because it determines how Apache serves PHP.
It is essential for your server’s performance that you select the handler that fits your situation. Selecting the right handler is just as important as the PHP version itself. One handler is not necessarily always better than another; it depends on your unique setup.

How to change the handler

1) Though WHM Panel :-
Main >> Service Configuration >> Configure PHP and SuExec
You simply select your PHP handler choice from the drop-down menu. Then hit “Save New Configuration”.
2) Via Shell

# /scripts/easyapache

OR

#/usr/local/cpanel/bin/rebuild_phpconfig

PHP handlers:-

CGI

CGI stands for: Common Gateway Interface. CGI handler will run PHP as a CGI module. CGI still runs PHP processes as the Apache ‘nobody’ user. However, if you have suEXEC enabled, it will allow you to see the user that made the request.
CGI is considered as Neither Secure Nor Fast. CGI is never recommended.

http://docs.cpanel.net/twiki/bin/view/AllDocumentation/WHMDocs/MorePhphandlers

DSO (mod_php)

Apache 1.3 introduced a method to load the modules dynamically called as Dynamic Sharing Object (DSO ) running in an Apache web server. DSO allows to load additional modules to apache webserver anytime without recompiling an entire server.
PHP as an Apache module is DSO.
It is also know as mod_php.
It runs PHP as an Apache module. This means that PHP scripts will run as the Apache user, which is the user: ‘nobody’.
Merits :-
– DSO is an older configuration
– Actually considered as the fastest PHP handler.
– Optimal utilization of resource usage.
-Additional modules can be added without recompilation of server-
De-Merits :-
– Files created by PHP scripts will have ownership as “NOBODY” – the situation is more prone to website compromise by an attacker. If an hacker finds an exploit in PHP script. This will give them the ability to modify files outside of that user’s account. This is really worst.
-Websites that need to upload files through PHP may face permission issues, due to conflicts settings of permissions.
– OS Platform restriction, since dynamic loading is not supported by some OS.
More Information

suPHP

suPHP stands for Single user PHP. suPHP also runs PHP as a CGI module instead of an Apache module. The main difference, and the advantage of having suPHP, is that with suEXEC enabled it runs the PHP scripts as the user calling them, rather than as the ‘nobody’ user.
suPHP is typically the default handler and is recommended by cPanel for serving PHP because you will be able to see which user owns the account that is running the PHP script.
suPHP is beneficial in that if you are using a file upload tool on your site (such as an automatic updater or theme/plug-in installer for WordPress), the files will already have the right ownership & permissions. Uploading and other WordPress functions will not work without suPHP or FastCGI.
Merits :-
– The security difference between suPHP and DSO is that suPHP confines an intruder to the particular user that he/she has affected. The exploit can’t cross accounts, however it can affect every single file the user owns as opposed to just the files writable by the webserver.
– suPHP also offers a security advantage that any php script that is not owned by the particular user (such as another account or root) will not be executable.
De-Merits :-
– suPHP generally runs a much higher CPU load. In addition, you CANNOT use an Opcode Cache (such as eAccelerator, Xcache or APC) with suPHP. It is strongly recommend that you install a caching plug-into supplement. If you find that your server is still continually struggling with CPU usage, you will want to consider switching to DSO or FastCGI.

FastCGI

FastCGI also called as FCGI or mod_fcgid it is similar to suPHP and/or is a high performance variation of CGI. It has the security/ownership benefits of suPHP in that PHP scripts will run as the actual cPanel user as opposed to ‘nobody’.
The difference with FastCGI is that it can drastically save on CPU performance and give speeds close to that of DSO. It can also be used with an opcode cacher like eAccelerator or APC, which can help further speed the loading of pages.
De-Merits :-
– FastCGI has a high memory usage. ( because rather than creating the PHP process each time it is called, like suPHP, it keeps a persistent session open in the background).
Go through below Image that will depict the PHP Handler :-

How to check current PHP Handler on server :-

# /usr/local/apache/bin/rebuild_phpconf –current

The post PHP Handler first appeared on Round Robin DNS Information and Services.

What Apache-Handler is ?

it is a means of telling the Apache web server ; how to process a given type of file. By default, Apache only handles certain file types. Apache handlers control how your site’s Apache web server manages certain file types and file extensions. Apache comes configured to handle CGI scripts and server-parsed files. The extensions include: .cgi, .pl, .plx, .perl, and .shtml.
If you wish Apache to do a different action, you will need to make a handler to tell Apache to perform that action. For example, if you use a file type that requires a special service to run it, such as a file with server side includes that is not named with a .shtml extension, you need to tell Apache to treat these files differently.

To get regular html pages to handle php code, you need to add this line to your .htaccess file.
AddHandler application/x-httpd-php5 .html .htm
It is highly recommended that you never allow html pages to automatically handle php or shtml, because this forces all of your html pages to be processed by the server first. Instead, please rename your files to .php or .shtml whenever possible.
HTML pages can be sent directly to a visitors browser, with no processing. However, PHP must be processed by the server before it is sent to the visitor, thus using more resources. (If you set that code in your .htaccess, it will work, and it will be more convenient, but it will also greatly increase your resource usage).
The Built-in Apache handlers are :-
default-handler : Send the file to the browser using default_handler() function, which is used to handle default static pages.
send-as-is : Send file with HTTP headers >> mod_asis)
cgi-script : Treat file as CGI script >> mod_cgi
imap-file : Parse as an imagemap rule file >> mod_imagemap
server-info : Get servers config info >> mod_info
server-status : Get servers status stas >> mod_status

The post Apache Handler first appeared on Round Robin DNS Information and Services.

APACHE MPM:-
MPM stands for Multiple Processing Modules. The main purpose of MPM is binding network ports on machine, accepting request and dispatching children to handle the requets.
Apache implements specialised MPM. MPM must be chosen while configuring and must be compiled in the server. MPM behaves like Apache module, the basic difference is only one MPM must be loaded into the server at any time. MPM are not actually modules that are loaded by apache. Instead they are compiled into apache.
We can compare MPM as an aperture which is responsible for accepting requests, spawning child processes; based on requests assigning child process and processing the request
List of Apache MPM modules are available. Refer the link for the same :-

http://httpd.apache.org/docs/2.0/mod/

Some of the well know and widely implemented MPM’s :-
1) Prefork
2) Event
3) Worker

CHECK WHICH MPM IS ACTIVE ?

#httpd –V or
#/usr/sbin/httpd –V | grep MPM

TYPES OF MPM :-
Basically, there are two major MPM’s

1) Prefork :-

A single control process is responsible for launching child processes which listen for connections and serve them when they arrive. Apache always tries to maintain several idle processes, which are ready to serve incoming requests. Therefore, client do not need to wait for a new child processes to be forked before their requests can be served.

“The prefork MPM runs multiple processes with each child process handling one connection”.
Prefork are non-threaded MPM
Preform is the default module given by an Apache.
Merits :-
-Stable and Secure
-Compatible with all implementations (cgi, fcgi, suPHP, DSO).
-Failure of one process won’t affect other connections.

De-Merits:-
-Simultaneous execution of multiple processes >> indicates more memory usage.
A typical configuration of the process controls in the Preform MPM could look as follows:

StartServers 8
MinSpareServers 5
MaxSpareServers 20
MaxClients 256
MaxRequestsPerChild 1000

More Information for parameters

2) Worker :-

Asingle control process that is, parent process is responsible for launching child processes. Each child process creates a fixed number of server threads as specified in the configuration, as well as listener thread which listens for connections and passes them to server for processing.

“The worker MPM has one control process that launches multi-threaded child processes which handles one connection per thread”.
Worker is a threaded MPM

Merits :-

-Multi-threaded design utilizes less memory usage irrespective of high connections.
-Fast performance.

De-Merits :-

-DSO Module Incompatible.
A typical configuration of the process-thread controls in the Worker MPM could look as follows:

ServerLimit 16
StartServers 2
MaxClients 150
MinSpareThreads 25
MaxSpareThreads 75
ThreadsPerChild 25

More Information for parameters

The post Apache MPM-Multi Processing Module first appeared on Round Robin DNS Information and Services.

What is DNS?

DNS stands for Domain Name System. A domain name is the unique name that is assigned to a website. DNS is the system that enables this to work. When you build a website, you also register a domain name. Then, you point the domain name to your website.

For a domain name to be assigned to a website, it first needs to be added to a DNS SERVER. A DNS (Domain Name System) SERVER is a large database containing each domain name and its corresponding IP address. For example, if the domain name “http://www.rrdnshosting.com” resolves to the website at 55.114.57.26 the DNS SERVER holds this information.

How does my Browser find the right Website?

1. Your browser checks it’s cache (memory) to see if it knows which IP address the domain name resolves to. If it knows, it will resolve it and display the web page.
2. If the domain name is unable to be resolved, the browser will check your hosts file for a DNS entry (more on hosts files below).
3. If there’s no entry in the hosts file, the browser will check the default DNS SERVER (specified via your computer’s network settings). This is usually your ISP’s DNS SERVER or your employer’s.
If the DNS SERVER has an entry for that domain name, the browser will display the applicable website.
4. If the default DNS SERVER doesn’t have an entry for that domain name, the browser will attempt to find a DNS SERVER somewhere in the world that does. This is made easier by the hierarchical structure of DNS SERVERS throughout the world.
If the domain name can be resolved, the applicable website will be displayed.
5. If the browser can’t find a DNS entry anywhere, it won’t be able to resolve the domain name (or URL). This is usually due to there being no entry for that domain name, or possible network problems between your computer and the DNS SERVER. In this case, your browser will display an error page.

The post Importance of DNS Servers first appeared on Round Robin DNS Information and Services.