Dedicated server – Page 26 – ServerPronto University

Support of the day March 24, 2011

Support of the day: Install 32-bit Software on 64-bit OS

This support solution is on installing a 32-bit app on an x64 system. Stated on the example of Java Development Kit installed on Fedora x64 bit.

Three layers are essential when it comes to 32/64bit compatibility:

– Processor

– Operating System

– Application

A 32 bit OS will run on a 32 or 64-bit processor, without any problems.

A 32-bit software on a 64 bit OS works but could cause difficulties even if the 64 bit systems are backward compatible with the 32-bit counterparts.

To run a 64 bit OS, you need support from its lower level (a 64-bit processor). Therefore a 64 bit OS does not work for a 32 bit CPU.

To run a 64-bit application, you need support from all lower levels (64 bit OS and 64-bit processor).

Linux commands:
Check your processor:

# cat /proc/cpuinfo

Check Kernel/System:

# uname -m

For our example, the perfect solution is to install a 64-bit version of JDK on the Fedora x64 bit operating system.

Here is the How-To-Do:

The first thing we need to do is get the JDK installer
JDK Home from Oracle.com

Once we have the installer in our local repository (as root):

chmod a+x  jdk-6u21-linux-x64-rpm.bin./jdk-6u21-linux-x64-rpm.bin

Next, we must add these two lines to the file: /etc/profile

JAVA_HOME=/usr/java/jdk1.6.0_21
pathmunge $JAVA_HOME/jre/bin after

At the end of the line that starts with export, we need to add this our JAVA_HOME variable, so the line should be like this:

export PATH USER LOGNAME MAIL HOSTNAME HISTSIZE INPUTRC JAVA_HOME

Then, we need to execute the next statements. Hint: Copy all the lines as it were just one.

export JAVA_HOME=/usr/java/jdk1.6.0_21
export JAVA_ALTERNATIVE_PRIORITY=16021
/usr/sbin/update-alternatives --install /usr/bin/java java $JAVA_HOME/bin/java $JAVA_ALTERNATIVE_PRIORITY
/usr/sbin/update-alternatives --install /usr/bin/javadoc javadoc $JAVA_HOME/bin/javadoc $JAVA_ALTERNATIVE_PRIORITY
/usr/sbin/update-alternatives --install /usr/bin/appletviewer appletviewer $JAVA_HOME/bin/appletviewer $JAVA_ALTERNATIVE_PRIORITY
/usr/sbin/update-alternatives --install /usr/bin/javah javah $JAVA_HOME/bin/javah $JAVA_ALTERNATIVE_PRIORITY
/usr/sbin/update-alternatives --install /usr/bin/javac javac $JAVA_HOME/bin/javac $JAVA_ALTERNATIVE_PRIORITY
/usr/sbin/update-alternatives --install /usr/bin/jar jar $JAVA_HOME/bin/jar $JAVA_ALTERNATIVE_PRIORITY

Then, we export the alternatives:

/usr/sbin/update-alternatives --auto java
/usr/sbin/update-alternatives --auto javadoc
/usr/sbin/update-alternatives --auto appletviewer
/usr/sbin/update-alternatives --auto javah
/usr/sbin/update-alternatives --auto javac
/usr/sbin/update-alternatives --auto jar

To confirm that our installation is successful:

java -version

Should give us output like this:

[root@yourMachine]# java -version
java version "1.6.0_21"
Java(TM) SE Runtime Environment (build 1.6.0_21-b02)
Java HotSpot(TM) 64-Bit Server VM (build 16.3-b01, mixed mode)

ServerPronto offers the best affordable and secure hosting service in all dedicated server packages.

Further information:
http://www.techsupportalert.com/content/32-bit-and-64-bit-explained.htm

http://wporta.wordpress.com/2010/07/06/installing-jdk-in-fedora-13/

Support of the day March 21, 2011

Manage users with Webmin and POP3/SMTP

You can manage and create users with Webmin by:

System/Users and groups/Create a new user

More information:

http://doxfer.webmin.com/Webmin/WebminUsers

If you want to add new domains, for example:

[email protected]
[email protected]

You need to add those domains to

/etc/mail/local-host-names

then in

/etc/mail/virtusertable

enter

[email protected] john
[email protected] sally

john and sally are local users

and rebuild config with

make -C /etc/mail/

ServerPronto offers the best affordable and secure hosting service in all dedicated server packages.

More information:

http://www.linuxselfhelp.com/quick/sendmail.html

Support of the day March 18, 2011

Software Management System yum

Managed system yum is software installation tool for Red Hat Linux and Fedora Linux. yum commands are typically run as.yum <command> <package name/s> By default, yum will automatically attempt to check all configured repositories to resolve all package dependencies during an installation/upgrade.

Here is a list of the most common and used yum commands:

yum list all

To list all packages that are available to use the commandyum.

yum install <package name/s>

Used to install the latest version of a package or group of packages. If no package matches the specified package name(s), they are assumed to be a shell glob, and any matches are then installed.

yum update <package name/s>

Used to update the specified packages to the latest available version. If no package name/s are specified, then yum will attempt to update all installed packages.

If the –obsoletes option is used (i.e. yum –obsoletes <package name/s>, yum will process obsolete packages. As such, packages that are obsoleted across updates will be removed and replaced accordingly.

yum check-update

This command allows you to determine whether any updates are available for your installed packages. yum returns a list of all package updates from all repositories if any are available.

yum remove <package name/s>

Used to remove specified packages, along with any other packages depend on the packages being removed.

yum provides <file name>

Used to determine which packages provide a specific file or feature.

yum search <keyword>

This command is used to find any packages containing the specified keyword in the description, summary, packager and package name fields of RPMs in all repositories.

yum localinstall <absolute path to package name/s>

Used when using yum to install a package located locally in the machine.

ServerPronto offers the best affordable and secure hosting service in all dedicated server packages.

More info under:

http://www.centos.org/docs/5/html/5.1/Deployment_Guide/s1-yum-useful-commands.html

http://yum.baseurl.org/wiki/YumCommands

Support of the day March 14, 2011

Establish connection for FTP daemon

Here are three steps that are necessary for the FTP daemon to allow connections:

A non-root user must be created.
The vsftp daemon must be started, you can do this with “/etc/init.d/vsftpd start”.
The firewall must allow port 21. You can add the firewall run in Webmin or by editing /etc/sysconfig/iptables, then restarting the firewall with “/etc/init.d/iptables restart”

The FTP user will have permission in their home directory. In order for the FTP user to have permission to upload, create any folder or allow different access, it is needed to grant the user access to that location using chown or chmod.

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Support of the day March 10, 2011

Configure WHM/cPANEL with a SSL Certificate

If you try to access CPanel WHM via https://server.domain.com:2087/ and the error â€œThere is a problem with this website’s security certificateâ€ comes up it can be because it uses a default SSL certificate loaded during the automated install and you need to update it with your personalized certificate.

To have a non-self-signed certificate you will need to create a certificate request using the domain and credentials you intend to connect with. Then upload that cert request to an SSL provider site where you have an account. After purchasing a certificate you can install it into CPanel.

Install a SSL Certificate for WHM port 2087 and cPanel port 2083:

1) Purchase / Install the Certificate for your fully qualified domain (ie: server.domain.com)

– You can find your fully qualified server URL in the WHM under:
>> Server Status >> Server Information (System Information)

– Then you will create a certificate for this domain under:
>> SSL / TLS >> Generate a SSL Certificate and Signing Request

– After purchasing your certificate, you will install the certificate under:
** THIS MAY SEEM SLOW – BE PATIENT – WAIT FOR A BOLD CONFIRMATION MESSAGE **
>> SSL / TLS >> Install a SSL Certificate and Setup the Domain

– After installation is complete, you can assign the new certificate to be your SHARED certificate under:
** This is NOT required but is a great benefit for your clients and helps brand your domain **
>> SSL / TLS >> Manage SSL Hosts

2) Test your new Certificate

– https://server.domain.com/
This should resolve and the cert should function properly before moving forward. If this does not work, you will need to review addition instruction on SSL installation.

– https://server.domain.com:2087/
This should NOT WORK but give you an invalid certificate error. The reason is that the certificate is installed for the domain only, and has not been assigned to the appropriate WHM/CPANEL services.

3) Install the CERT for the WHM and CPANEL Service (this is the step you don’t think about!!)

Service Configuration >> Manage Service SSL Certificates
> Select “Install New Certificate” for the “cPanel/WHM/Webmail Service”
> Select Domain this CRT is for “Browse”
> Pick the full server cert you installed “server.domain.com”
> Press “Submit” to install

4) Test your Service Certificate

https://server.domain.com:2087/

ServerPronto offers the best affordable and secure hosting service in all dedicated server packages.

More information under:

Manage SSL Certs

Configure WHM cPanel SSL Certificate

Support of the day March 9, 2011

Change configuration settings in Apache with .htaccess files

When changing configuration settings in Apache using directives in .htaccess files make sure:

- – The full directory content is listed with: Â Â ls -a to view hidden file that start with “.”
- – ensure Apache can use .htaccess, it is necessary to verify that option is enabled
  - – enabled .htaccess in httpd.conf

How-To-Do:

http://httpd.apache.org/docs/2.2/howto/htaccess.html

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Support of the day March 7, 2011

Setup FTP Server

If you have problems setting up an FTP server or issues accessing your FTP site, here are two basic tips that have helped our customers before to make their FTP server work properly.

Check if the FTP daemon you are using is installed correctly and is running
Verify the software firewall rules

The FTP server should be allowed to accept TCP connections to port 21, and to make TCP connections from port 20 to any port

For further details, here are helpful instructions on how to set up your FTP server:

FTP Configuration in Linux

http://www.linuxhomenetworking.com/wiki/index.php/Quick_HOWTO_:_Ch15_:_Linux_FTP_Server_Setup#Introduction

http://www.mdjnet.dk/ftp.html

FTP Configuration in Windows Server 2008

http://learn.iis.net/page.aspx/309/configuring-ftp-firewall-settings/

FTP Configuration using cPanel

http://docs.cpanel.net/twiki/bin/view/AllDocumentation/CpanelDocs/FTPAccounts

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Support of the day March 6, 2011

Check installed hardware in Linux

At ServerPronto we build our customerâ€™s orders precisely and accurately. We do double duty on quality control during the provisioning process, still, we encourage our customers to check the hardware settings of the server you ordered.

Linux commands to check hardware:

Harddrive

fdisk â€“l

Memory

cat /proc/meminfo

CPUcat /proc/cpuinfo

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Support of the day March 4, 2011

Manage slave drives and partitions in Linux

Managing the hard drive on a server, meaning creating/ removing partitions and formatting/ activating slave drives is a vital step in setting up a server that we usually do for our customers. But sometimes users want to manage their storage by themselves; here is how to do it:

Linux:

to get an overview of your hard drives and to see partitions such as /dev/hda and /dev/hdb

fdisk â€“l

to manage the slave drive

fdisk /dev/hdb

p - to see partitions

d â€“ to delete partitions

n - to create new partition

m â€“ to display help in fdisk

w â€“ to write changes

reboot

to format the partition

mke2fs â€“j /dev/hdb1

go into nano /etc/fstab and add the following to the end of the file

/dev/hdb1    /home    ext3    defaults    1 2

to make the partitions usable and visible with df -h

mount â€“a

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Windows:

Access the built-in utility “Disk Management“. Go into the Control Panel -> go under Administrative Tools -> Computer Management -> on the left-hand side underneath Storage -> Disk Management.

Look on the bottom right and you’ll see something that looks like this picture. The disk with all of the unallocated space is what you’re after. Right, click on it. Select New Partition.

A wizard will pop up and walk you through this process. Choose a partition size. If this is a secondary drive then you’re obviously after pure storage space so just make it a primary partition and allocate 100% of your space to it.

The followed screen looks like this. Just clicking next until you get here.

If you’re only using Windows 2000/XP/Vista/Windows 7 and Windows server 2000/2003/2008, it is suggested using NTFS. If you’re dual booting then Fat32 would probably be a good idea if the other OS can’t read NTFS.

For NTFS the default cluster size is 4K which is pretty much the best tradeoff between speed and storage space.

Volume label is nothing other than the name you want it to be called.

Make sure you select the quick format or else it’ll be a while before you can use the disk.

Click next it’s just a summary of what you told it to do.

Click next and soon the new drive is available.

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More information at: http://www.easeus.com/resource/install-ide-hard-drive.htm

Support of the day March 2, 2011

Open/Close Ports on Ubuntu distributions

IPTables is an application program that allows to set up, maintain, and inspect the tables of IP packet filter rules provided by the Linux kernel.

All IPTables rules are stored on /etc/iptables.rules
You can open/close any port from it and then restart the network by running “etc/init.d/networking restart”

Before opening or closing ports, we recommend to first verify if the port is open or closed and who is using the port. There a number of different commands:

Commands to verify ports:

nmap IP#

nmap localhost

netstat â€“ntulp

to verify the single port

netstat -nap | grep Â <port #>

to list all current rules in iptables

iptables -L

For opening a TCP port:

iptables -A INPUTÂ  -p tcp â€“dport <port #> -j ACCEPT

For opening a UDP port:

iptables -A INPUT -p udp â€“sport <port #>Â  -j ACCEPT

Save changes:

iptables-save > /etc/iptables.rules

If you need to disable the firewall temporarily, you can flush all the rules using:

iptables -F

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ServerPronto offers the best affordable and secure hosting service in all dedicated server packages.

For more detailed information visit

Iptables Description by Ubuntu Manuals

Iptables How-To for Ubuntu by Ubuntu Manuals

Iptables How-To for Debian by wiki.debian.org