Disable Directory Browsing in Linux Apache Server

Disable directory browsing using .htaccess:-
Open your .htacces file

Look for Options Indexes
If Options Indexes exists modify it to Options -Indexes or else add Options -Indexes as a new line
The directory browsing feature should be disable by now

Disable directory browsing using httpd.conf:-

Open your httpd.conf, normally it’s located at /usr/local/apache/conf or /etc/httpd.conf
Go to your own Virtual Host settings and look for “Options Indexes”
Change the Indexes to -Indexes if Option Indexes exists or else add the Options -Indexes line
Restart your apache web server.

The directory browsing feature should be disable by now

Disable directory browsing in CPanel Share Hosting enviroment:-

Login to your CPanel
Click on Index Manager
Directory will be list down. Click on the directory name which you want to disable the directory browsing
Select No Index and click Save

The directory browsing feature should be disable by now
Once you disable directory browsing, visitor will not able to browse your directory by accessing the directory directly (if there is no index.html file).
This will protect your files from exposing to the public.

Re-install bootstrap code (GRUB)

Please perform the following steps:

Boot from CentOS installation disc (for example, CD #1 or DVD).
Type “linux rescue” at the “boot:” prompt.

Mount all filesystems in read-write mode.
Change root to real root (‘/’) on your hard disk:

# chroot /mnt/sysimage

Re-install bootstrap code (GRUB).
If you wish to re-install GRUB to the MBR on a SCSI or SATA disk (/dev/sda):
# grub-install /dev/sda

If you wish to re-install GRUB to the PBR of Partition #2 on a SCSI or SATA disk (/dev/sda2):
# grub-install /dev/sda2

If you wish to re-install GRUB to the MBR on an IDE disk (/dev/hda):
# grub-install /dev/hda

If you wish to re-install GRUB to the MBR on a HP Smart Array disk (/dev/c0d0):
# grub-install /dev/cciss/c0d0

Alternative Recovery from GRUB Issues – Super Grub Disk
Super Grub Disk has a variety of open source boot recovery tools. For CentOS legacy GRUB SuperGRUB works well.

—

Apache Error Response Codes & Explanation

100-199

Silent Response Codes that signify that a request has been received and is currently being processed.

100

The request has been completed and the rest of the process can continue.

101

The user’s request to switch protocols (like from FTP to HTTP) was accepted.

200-299

Silent codes that confirm that requests have completed successfully.

200

Ok — the file which the client requested is available for transfer. This is the response code you want to see all of your users receiving.

201

When new pages are created by posted form data or by a CGI process, this is confirmation that it worked.

202

The client’s request was accepted, though not yet processed.

203

The information contained in the entity header is not from the original site, but from a third party server.

204

If you click a link which has no target URL, this response is elicited by the server. It’s silent and doesn’t warn the user about anything.

205

This allows the server to reset any content returned by a CGI.

206

Partial content — the requested file wasn’t downloaded entirely. This is returned when the user presses the stop button before a page is loaded, for example.

300-399

A redirection is occurring from the original request.

300

The requested address refers to more than one file. Depending on how the server is configured, you get an error or a choice of which page you want.

301

Moved Permanently — if the server is set up properly it will automatically redirect the reader to the new location of the file.

302

Found — page has been moved temporarily, and the new URL is available. You should be sent there by the server.

303

This is a “see other” SRC. Data is somewhere else and the GET method is used to retrieve it.

304

Not Modified — if the request header includes an ‘if modified since’ parameter, this code will be returned if the file has not changed since that date. Search engine robots may generate a lot of these.

400-499

Request is incomplete for some reason.

400

Bad Request — there is a syntax error in the request, and it is denied.

401

The request header did not contain the necessary authentication codes, and the client is denied access.

402

Payment is required. This code is not yet in operation.

403

Forbidden — the client is not allowed to see a certain file. This is also returned at times when the server doesn’t want any more visitors.

404

Document not found — the requested file was not found on the server. Possibly because it was deleted, or never existed before. Often caused by misspellings of URLs.

405

The method you are using to access the file is not allowed.

406

The requested file exists but cannot be used as the client system doesn’t understand the format the file is configured for.

407

The request must be authorised before it can take place.

408

Request Timeout — the server took longer than its allowed time to process the request. Often caused by heavy net traffic.

409

Too many concurrent requests for a single file.

410

The file used to be in this position, but is there no longer.

411

The request is missing its Content-Length header.

412

A certain configuration is required for this file to be delivered, but the client has not set this up.

413

The requested file was too big to process.

414

The address you entered was overly long for the server.

415

The filetype of the request is unsupported.

500-599

Errors have occurred in the server itself.

500

Internal Server Error — nasty response that is usually caused by a problem in your Perl code when a CGI program is run.

501

The request cannot be carried out by the server.

502

Bad Gateway — the server you’re trying to reach is sending back errors.

503

Temporarily Unavailable — the service or file that is being requested is not currently available.

504

The gateway has timed out. Like the 408 timeout error, but this one occurs at the gateway of the server.

505

The HTTP protocol you are asking for is not supported.

Network interface bonding in RHEL4.0 – How to

Finally today I had implemented NIC bounding (bind both NIC so that it works as a single device). We have two Dell servers that need setup with Intel Dual Gig NIC. My idea is to improve performance by pumping out more data from both NIC without using any other method.

This box act as heavy duty ftp server. Each night I need to transfer over 200GB data from this box to another box. Therefore, the network would be setup is two servers on a switch using dual network cards. I am using Red Hat enterprise Linux version 4.0.

Linux allows binding multiple network interfaces into a single channel/NIC using special kernel module called bonding. According to official bonding documentation, “The Linux bonding driver provides a method for aggregating multiple network interfaces into a single logical “bonded” interface. The behavior of the bonded interfaces depends upon the mode; generally speaking, modes provide either hot standby or load balancing services. Additionally, link integrity monitoring may be performed.”

Setting up bounding is easy with RHEL v4.0.

Step #1: Create a bond0 configuration file

Red Hat Linux stores network configuration in /etc/sysconfig/network-scripts/ directory. First, you need to create bond0 config file:

# vi /etc/sysconfig/network-scripts/ifcfg-bond0
Append following lines to it:
DEVICE=bond0
IPADDR=192.168.1.20
NETWORK=192.168.1.0
NETMASK=255.255.255.0
USERCTL=no
BOOTPROTO=none
ONBOOT=yes
Replace above IP address with your actual IP address. Save file and exit to shell prompt.

Step #2: Modify eth0 and eth1 config files:

Open both configuration using vi text editor and make sure file read as follows for eth0 interface
# vi /etc/sysconfig/network-scripts/ifcfg-eth0
Modify/append directive as follows:
DEVICE=eth0
USERCTL=no
ONBOOT=yes
MASTER=bond0
SLAVE=yes
BOOTPROTO=none

Open eth1 configuration file using vi text editor:

# vi /etc/sysconfig/network-scripts/ifcfg-eth1
Make sure file read as follows for eth1 interface:
DEVICE=eth1
USERCTL=no
ONBOOT=yes
MASTER=bond0
SLAVE=yes
BOOTPROTO=none
Save file and exit to shell prompt.

Step # 3: Load bond driver/module

Make sure bonding module is loaded when the channel-bonding interface (bond0) is brought up. You need to modify kernel modules configuration file:
# vi /etc/modprobe.conf
Append following two lines:
alias bond0 bonding
options bond0 mode=balance-alb miimon=100
Save file and exit to shell prompt. You can learn more about all bounding options in kernel source documentation file (click here to read file online).

Step # 4: Test configuration

First, load the bonding module:

# modprobe bonding
Restart networking service in order to bring up bond0 interface:
# service network restart

Verify everything is working:
# less /proc/net/bonding/bond0
Output:

Bonding Mode: load balancing (round-robin)
MII Status: up
MII Polling Interval (ms): 0
Up Delay (ms): 0
Down Delay (ms): 0

Slave Interface: eth0
MII Status: up
Link Failure Count: 0
Permanent HW addr: 00:0c:29:c6:be:59

Slave Interface: eth1
MII Status: up
Link Failure Count: 0
Permanent HW addr: 00:0c:29:c6:be:63

List all interfaces:

# ifconfig
Output:
bond0 Link encap:Ethernet HWaddr 00:0C:29:C6:BE:59
inet addr:192.168.1.20 Bcast:192.168.1.255 Mask:255.255.255.0
inet6 addr: fe80::200:ff:fe00:0/64 Scope:Link
UP BROADCAST RUNNING MASTER MULTICAST MTU:1500 Metric:1
RX packets:2804 errors:0 dropped:0 overruns:0 frame:0
TX packets:1879 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:250825 (244.9 KiB) TX bytes:244683 (238.9 KiB)

eth0 Link encap:Ethernet HWaddr 00:0C:29:C6:BE:59
inet addr:192.168.1.20 Bcast:192.168.1.255 Mask:255.255.255.0
inet6 addr: fe80::20c:29ff:fec6:be59/64 Scope:Link
UP BROADCAST RUNNING SLAVE MULTICAST MTU:1500 Metric:1
RX packets:2809 errors:0 dropped:0 overruns:0 frame:0
TX packets:1390 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:251161 (245.2 KiB) TX bytes:180289 (176.0 KiB)
Interrupt:11 Base address:0×1400

eth1 Link encap:Ethernet HWaddr 00:0C:29:C6:BE:59
inet addr:192.168.1.20 Bcast:192.168.1.255 Mask:255.255.255.0
inet6 addr: fe80::20c:29ff:fec6:be59/64 Scope:Link
UP BROADCAST RUNNING SLAVE MULTICAST MTU:1500 Metric:1
RX packets:4 errors:0 dropped:0 overruns:0 frame:0
TX packets:502 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:258 (258.0 b) TX bytes:66516 (64.9 KiB)
Interrupt:10 Base address:0×1480

Now you have bond multiple network interfaces into a single channel (NIC).

Courtesy : http://www.cyberciti.biz

Upgrading perl 5.8.8 in C-Panel server

The version of perl (v5.8.7) is too old. There are known problems that cannot be worked around with this version of perl. It is HIGHLY recommended that you upgrade to v5.8.8 or later. Any module install failures should be ignored until perl has been upgraded as some modules will not be able to install with this version of perl.

You can ensure that each installed module gets carried over to the updated Perl build with the use of the “autobundle” CPAN feature.

You can create a bundle of the currently installed modules by executing the following while logged in via SSH as root:

perl -MCPAN -e ‘autobundle’

Once completed, you should see the following output before getting returned to the shell:

‘Wrote bundle file /home/.cpan/Bundle/Snapshot_2007_08_16_00.pm’

Once you’ve made note of this file name, you can proceed with the update.

On linux based systems, you should be able to update Perl using the installer provided at layer1.cpanel.net:

cd /root
wget http://layer1.cpanel.net/perl588installer.tar.gz
tar -zxf perl588installer.tar.gz
cd perl588installer
./install -optimize-memory

On FreeBSD based systems, you will need to install Perl from ports.

This will take a few minutes, so take a coffee break and check the status when you return. Once the update has completed, you can install all previously installed modules from the CPAN bundle by executing the following (with the bundle name adjusted to the name of the bundle generated earlier):

perl -MCPAN -e ‘install Bundle::Snapshot_2007_08_16_00′

This should install each of the modules present in the bundle, assuming there are no issues during the installation (dependencies, network, etc).

Once this has completed, execute the following to ensure that all modules required by cPanel are installed, and restart cPanel:

/usr/local/cpanel/bin/checkperlmodules

Visitor Map

Monitoring Network Traffic Usage using Bandwidthd

It is important to know traffic usage of your client if you’re a Linux network administrator. You can monitor your client in text mode, graphic mode or html exported like mrtg, cacti or bandwidthd and one of my favorite bandwidth monitor is Bandwidthd.

You don’t need any database or snmp connection to monitor all of your client on bandwidthd, all you need just libcap, libpng, libgd and apache installed on your Linux system. And other good news is bandwidthd monitor all of your connected client per IP and per connection protocol.

Installing Bandwidthd

Prepare your Linux and download bandwidthd for Linux here. Next extract bandwidth using tar -zxvf command.

Goto extracted directory and type ./configure && make install to install bandwidth to your system.

Configuring Bandwidthd

By default all installed bandwidthd files placed on /usr/local/bandwidthd/folder. Now goto bandwidthd installed directory and CD to etc, you’ll find bandwidthd config file there. Open bandwidthd.conf using your favorite text editor like vi or nano and start edit bandwidthd config file suit your network.

Save your config and start bandwidthd using/usr/local/bandwidthd/bandwidthd. Put that command to your /etc/rc.localfile so bandwidthd can start on every time Linux boot.

Configuring Apache

You will can’t see your graphic report until you set/usr/local/bandwidthd/htdocs/ folder to set as apache virtual directory. Add below line to your apache config file.

Alias /bandwidthd “/usr/local/bandwidthd/htdocs”
<Directory “/usr/local/bandwidthd/htdocs”>
Order Allow,Deny
Allow from All
</Directory>
Save your work and restart apache. Next open your browser and point to http://yourlinuxserver/bandwidth.

Happy trying and good luck.

Courtesy:  http://infodotnet.blogspot.com

2010 in review

The stats helper monkeys at WordPress.com mulled over how this blog did in 2010, and here’s a high level summary of its overall blog health:

The Blog-Health-o-Meter™ reads Fresher than ever.

Crunchy numbers

A helper monkey made this abstract painting, inspired by your stats.

A Boeing 747-400 passenger jet can hold 416 passengers. This blog was viewed about 13,000 times in 2010. That’s about 31 full 747s.

 

In 2010, there were 23 new posts, growing the total archive of this blog to 59 posts. There were 3 pictures uploaded, taking up a total of 34kb.

The busiest day of the year was September 28th with 104 views. The most popular post that day was How To Create LVM Using pvcreate, vgcreate, lvcreate, and lvextend Commands.

Where did they come from?

The top referring sites in 2010 were google.com, google.co.in, pcproblems.wordpress.com, dray.com.np, and computertrick.wordpress.com.

Some visitors came searching, mostly for pvcreate, clear sendmail queue, redmine migration, sendmail clear queue, and howto pvcreate.

Attractions in 2010

These are the posts and pages that got the most views in 2010.

1

How To Create LVM Using pvcreate, vgcreate, lvcreate, and lvextend Commands August 2010
1 comment

2

How to install DNS server on CentOS 5. February 2010
1 comment

3

Installing Redmine & Redmine Migration Guide June 2009
2 comments

4

How to clear sendmail queue June 2009
1 comment

5

RKHunter Configuration Guide January 2010
1 comment

Remote Installation of Fedora Distributions Using PXE boot

If you want to deploy many machines, then it is a pain to go from machine to machine with 4 CDs. Like RIS (Remote Installation Service) in Windows, Fedora also offers you a similar remote installation facility via PXE LAN booting. For this, you will require a DHCP server, Apache and TFTP server running on Fedora.

Firstly, install Fedora completely. Then, on that machine, make a folder named  /Fedora on root and copy all the contents of the Fedora CDs in this folder. Remember that you are mounting the CDs and copying the contents and not just copying the ISOs. While copying the files from the CDs, you will be asked for permission to overwrite few files and folders.

Once you have created a copy of the CDs on the machine, you have to create a kick start file, which has answers to the questions asked during the installation process.

To make this file, launch ‘kickstart’ from Start>Systems, this will open a GUI Kickstart configuration interface.

Here, you can set pre-installation settings such as keyboard type, language, time zone, mouse, display, root password, etc. Fill all the entries according to your setup requirements and save the file. It saves a file with name ks.cfg.

Copy this file to the location where you have copied the Fedora2006 files from the CD.

Host installer
In order to remotely install Fedora via HTTP, you have to configure apache server to host the installer. To do this, launch Start>system>HTTP. This will open an interface to configure the apache web server. Here, select the main tab and give the IP address of the same machine, where you are hosting the apache server. Next, select the ‘virtual host’ tab and select add new host and double click the new virtual host you have created. This will open its properties dialog. Here, under basic setup set the ‘document root directory’ to the location where you copied the Fedora CDs.

In our case it is /fedora. Now, from the same properties window, click on the performance tab and add the directory of your Fedora installer that you have copied above. Once you are through with this, save the settings by clicking the Ok button. After this, start apache server by issuing this command.

#service httpd start

Now, open a web browser and check that the web server is working properly. Make sure it displays the directory structure of the Fedora installer folder on the web page.

Configuring TFTP Server
TFTP stands for Trivial File Transfer Protocol, a simpler form of the File Transfer Protocol (FTP).

The next step is to configure TFTP server on your installer server in such a way that it can remotely boot another PC over a network. In order to do this, open a terminal and issue the following commands.

# cp /pcqlinux/isolinux/* /tftpboot/linux-install/
# cp /tftpboot/linux-install/isolinux.cfg /tftpboot/linux-install/pxelinux.cfg/default

The above commands will copy all the boot files from the folder where you have dumped the entire Fedora CDs to the TFTP server.

Now open /tftpboot/ linux-install/pxelinux.cfg /default file in a text editor and change the following entries as follows

label linux
kernel vmlinuz
append initrd=initrd.img ramdisk_size=8192 s=http://192.168.3.1/pcqlinux/ks.cfg
label text
kernel vmlinuz
append initrd=initrd.img text ramdisk_size=8192 ks=http://192.168.3.1/pcqlinux/ks.cfg

(Here 192.168.3.1 is the IP address of the hosting server, where you have hosted the Fedora installer, you should change it according to your settings).

After this you have to enable the TFTP server so that the TFTP server

automatically gets started on booting the Fedora server. For doing this, run ‘setup’ command from the terminal. It will open a CLI interface, here select ‘Services’ and from the list select ‘tftp’ by pressing space bar key and click the Ok button to save the settings .

Configure DHCP server

Now, you have to configure the DHCP server on your installation server, so that the diskless clients can get IP addresses from the RIS server and remotely boot and start the Fedora installer. To do this open the /etc/dhcpd.conf file and add the following lines as shown below.

ddns-update-style
none;
default-lease-time
21600;
max-lease-time
21600;
option subnet-mask
255.255.255.0;
option broadcast-address
192.168.3.255;
option domain-name-servers
192.168.3.78; #<– RIS Server IP
option domain-name
“ris.pcquest.local”;
# <–domain name
option option-128 code 128 = string;
option option-129 code 129 = text;
subnet  192.168.3.0 netmask 255.255.255.0 {
range dynamic-bootp
192.168.3.10 192.168.3.253; # <– DHCP IP Ranage
filename
“/linux-install/pxelinux.0″;  #<- Boot image File

}
Restart the DHCP server.
# Service dhcpd restart

With this your Remote Installation server is ready.

Boot the client machines from the Remote Installation Server and you will get the Installer booting screen. Thereafter, and you can start the installation process on it.

Troubleshooting – Client not booting?

If your PC is not booting off the remote boot server, then two things could be wrong. Firstly, its network card may not be PXE boot enabled. If it is PXE enabled, check the BIOS to see whether the boot from network option is enabled

 

Cpanal – Mail not receiving error R=central_filter T=**bypassed**

Recently I got very interesting issue and it took very long time to figure our. The problem was I was able to send/receive email to other accounts but not able to send/receive to my own account means test@test.com to test@test.com. Here is what I was getting in error logs (Cpanel server).

gin:test@test.com S=789 id=63311.122.252.239.20.1239477600.squirrel@test.com
2009-04-11 14:20:00 1LsikC-00037z-NP => /dev/null
R=central_filter T=**bypassed**

Then here is what I found in cpanel forums:

central_filter refers to the email filters you’ve set up in cPanel – stored in /etc/vfilters/. Looks like you’ve got a filter set up to drop certain emails.

Then I renamed my domain name files in /etc/vfilters/ and I got this fixed, hope this will help you