CentOS is a free (as in beer and speech) GNU/Linux distribution that is community driven and based on source code released from RedHat.

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48
votes
2answers
6k views

Why is it so difficult to upgrade between major versions of Red Hat and CentOS?

"Can we upgrade our existing production EL5 servers to EL6?" A simple-sounding request from two customers with completely different environments prompted my usual best-practices answer of "yes, but ...
103
votes
17answers
125k views

CentOS vs. Ubuntu [closed]

I had a web server that ran Ubuntu, but the hard drive failed recently and everything was erased. I decided to try CentOS on the machine instead of Ubuntu, since it's based on Red Hat. That ...
4
votes
3answers
4k views

How to diagnose causes of oom-killer killing processes

I have a small virtual private server running CentOS and www/mail/db, which has recently had a couple of incidents where the web server and ssh became unresponsive. Looking at the logs, I saw that ...
29
votes
1answer
5k views

Why are my XFS filesystems suddenly consuming more space and full of sparse files?

I've run XFS filesystems as data/growth partitions for nearly 10 years across various Linux servers. I've noticed a strange phenomenon with recent CentOS/RHEL servers running version 6.2+. Stable ...
13
votes
4answers
4k views

Managing an application across multiple servers, or PXE vs cfEngine/Chef/Puppet

We have an application that is running on a few (5 or so and will grow) boxes. The hardware is identical in all the machines, and ideally the software would be as well. I have been managing them by ...
24
votes
2answers
57k views

How do I configure LDAP on Centos 6 for user authentication in the most secure and correct way?

During the last couple of days I have been using a lot of F-words, while browsing Internet for good documentation about how to setup an LDAP-server. So far I have found none, but plenty that are less ...
30
votes
4answers
10k views

Allow SFTP but disallow SSH?

I'm starting a very little hosting company for a few friends and little clients, nothing big. I want to give my "clients" the right to manage their files on the server. I hate FTP as it is not secure ...
18
votes
12answers
76k views

How to find out details about hardware on the Linux machine?

-i.e - how to get a full list of hardware components in command line (on a machine with no window system) Thank you.
11
votes
5answers
4k views

Log all commands run by admins on production servers

It is company policy for admins to login to the servers via a personal username, and then run sudo -i to become root. Upon running sudo -i, sudo will create an environmental variable called ...
11
votes
6answers
8k views

How can I determine what is taking up so much space?

I was using df -h to print out human readable disk usage. I would like to figure out what is taking up so much space. For instance, is there a way to pipe this command so that it prints out files that ...
10
votes
4answers
25k views

How to configure vsftpd to work with passive mode

Whenever I install vsftpd on centos, I only setup the jail environment for the users and rest is default configuration of vsftpd. I create user and try to connect with filezila ftp client but I could ...
6
votes
2answers
7k views

Setting up Exim to forward mail

I'm trying to setup Exim on a fresh CentOS install so that it will receive mail for a collection of given addresses, and forward the mail respectively to another address. For example, receiving mail ...
23
votes
13answers
4k views

Linux IO monitoring per file?

I am interested in a utility or process for monitoring disk IO per file on CentOS. On Win2008, the resmon utility allows this type of drilldown, but none of the Linux utilities I have found do this ...
18
votes
12answers
21k views

Disable local delivery in Sendmail

I am using Sendmail on a Centos server to send email for PHP scripts, but the problem is that mail is delivered to a local mailbox on the machine rather than what is specified in the MX records for ...
7
votes
1answer
21k views

Configure Postfix to send/relay emails Gmail (smtp.gmail.com) via port 587

Using Centos 5.4, with Postfix. I can do a mail foo@gmail.com subject: blah test . Cc: and the msg gets sent to gmail, but it resides in the spam folder, which is to be expected. My goal is to ...
15
votes
3answers
27k views

How do I upgrade to the latest PHP version in CentOS with yum?

I found some blog posts about this, but it's rather lack of descriptions on possible side effects. I could really use some detailed on these steps: How to add a repo that provides PHP 5.4 into yum ...
14
votes
2answers
28k views

Allowing FTP with IPTables

My current scenario involves allowing various rules, but I need ftp to be accessible from anywhere. The OS is Cent 5 and I am using VSFTPD. I can't seem to get the syntax correct. All other rules ...
10
votes
8answers
30k views

How do I install PHP 5.3 on CentOS?

I have to install PHP 5.3 on my CentOS server. If I do yum install php, the base repository installs 5.1.6 which is too old for the applications I need to install. So I've been trying to use the IUS ...
6
votes
6answers
26k views

CentOS 5: How to resolve php53 RPM dependency conflict with php-foo and php-common?

We are running a CentOS 5.6 system, and want to install php53 with php-mcrypt. However, this introduces a dependency conflict between php-common & php53-common. Does anyone have a good workaround ...
1
vote
3answers
2k views

Disable access logging for domains. (Using CentOS & Apache)

I am trying to disable access logging for domains on my dedicated server for over 10 HOURS. I read over 70 pages while I'm searching. I asked on Parallel's forum, I asked stackoverflow in another ...
1
vote
1answer
2k views

Newer GLIBC for RHEL/CentOS 5.x

I have a situation where a group of developers is attempting to deploy a binary application to a series of RHEL 5.5 and CentOS 5.5 servers. Unfortunately, the application was developed on another ...
17
votes
4answers
2k views

Monitoring production server

Hey all, We have 3 dedicated server, splitted in several VPS using openVZ. We're using munin to monitor the VPS with the production sites, and monit on some one of the VPS to make sure it restarts the ...
10
votes
3answers
1k views

The A to Z of setting up a Linux box for secure local hosting

I am in the process of reinstalling the OS on a machine that will be used to host a couple of applications for our business. The applications will be local only; access from external clients will be ...
8
votes
2answers
3k views

CentOS 6 doing lots more IO than CentOS 5

I'm benchmarking an application on two identical servers, one is Centos 5.8 and the other is Centos 6.2. My application is running much slower (50% or less) on the Centos 6.2 machine. In attempting ...
7
votes
1answer
4k views

CentOS 5 - realtime patch

Where can I download precompiled CentOS 5 kernel including realtime patch? Or I need to compile it myself (if yes, how to do that)?
6
votes
4answers
2k views

Record everything on command line centos /fedora/ ubuntu

we are 100% Linux user across the network and we do work round clock, what happens shift change next admin come to his shift on that time what all issues comes he get resolve the issues but they just ...
4
votes
1answer
1k views

How to Tee udp packets onto a different host

I would like to clone incoming UDP packets onto a different host, I found a way to do it Here but I could not build xtables-addons on centos 5.3 . Is there any other way to tee upd packets?
3
votes
8answers
2k views

MySQL is running VERY slow on CentOS 6x (not 5x)

I have two servers: a VPS and a laptop. I recently re-built both of them, and MySQL is running about 20 times slower on the laptop. Both servers used to run CentOS 5.8 and I think MySQL 5.1, and the ...
2
votes
2answers
12k views

Postfix: lost connection with *somehost* while receiving the initial server greeting

I had Postfix installed on CentOS earlier (several months ago) and it was working fine. Due to the fact of the many brute-force attempts and considering that I didn't use it almost at all I shut ...
1
vote
2answers
5k views

Centos: multiple IP addresses

I just bought 10 extra IPs from my host. How do I point these at my CentOS 5 server?
8
votes
3answers
7k views

How to Upgrade PHP to 5.4.10 on CentOS 6.3

# cat /etc/redhat-release CentOS release 6.3 (Final) # php -v PHP 5.3.3 # yum update php No Packages marked for Update How do I upgrade to the latest version PHP 5.4.10 (Current stable) ?
3
votes
3answers
4k views

second ip address on the same interface but on a different subnet

Is it possible in CentOS 5.7 64bit to have a second IP address on one interface (eg. eth0) - alias interface configuration - in a different subnet? Here is the original config for eth0 more ...
3
votes
2answers
2k views

Iptables port forwarding on OpenVZ CEntOS container

I am trying to setup a simple port forwarding on an OpenVZ container that is running CentOS 5.5. When I run a command I get errors. iptables -t nat -A PREROUTING -p tcp --dport 80 -j REDIRECT ...
2
votes
2answers
6k views

How to change Linux services startup/boot order?

As the question is clear from the title, how do I change Linux services startup/boot order?
0
votes
1answer
507 views

Hacked CentOS 5 server - possible rootkit installed? [duplicate]

Possible Duplicate: How do I know if my Linux server has been hacked? My server's been hacked EMERGENCY I am running CentOS 5.3 and here is the result of "chkrootkit": Possible t0rn ...
0
votes
2answers
364 views

Centos - Automatically issue a command after rebooting

I need to automatically issue a command on my CentOS 4.8 server after it reboots and/or powers up. Can someone please tell me where I can place this? Is there a configuration file somewhere for this? ...
78
votes
14answers
63k views

How do you install Node.JS on CentOS?

I've found numerous installation instructions for Node.js but they all seem so complicated -- I'm not a super sys admin but I can get around. I have yum on the system, but I didn't find any node.js ...
7
votes
1answer
29k views

What does “<service_name> dead but subsys locked” mean?

I'm trying to run memcached on a centos box and it runs for a while, but then ends up in this state: memcached dead but subsys locked netstat shows this: tcp 0 0 :::11211 ...
5
votes
2answers
2k views

Tips for optimizing RHEL/CentOS kickstart workflow

I'm working in an environment that consists of CentOS systems located in multiple data centers and office locations. I've been using a reasonable kickstart with a solid post-install script, but want ...
5
votes
9answers
3k views

Linux Server Performance Monitoring

I'm looking to monitor performance on my Linux servers (which happen to be Centos). What are the best tools for monitoring things in realtime such as: Disk Performance I/O, swapping etc.. CPU ...
4
votes
2answers
6k views

Stop DoS attacks with an IP tables rule?

I was wondering if I could prevent small (D)DoS attacks with a simple IP tables rule? By small I mean that they are flooding my web server with about 400+ requests from one or two IP addresses. I ...
3
votes
3answers
5k views

cakephp & nginx config/rewrite rules

Hi somebody please help me out, I've asked this at stackoverflow as well but not got much of a response and was debating whether it was programming or server related. I’m trying to setup a cakephp ...
2
votes
2answers
5k views

Mount a Windows DFS Namespace in Linux

I've got a Windows DFS setup with a few namespaces, and I need a way of accessing them via CentOS. Any ideas? I've had a look at CIFS mounting, but it won't support the namespace (each separate ...
6
votes
4answers
6k views

Install recent ImageMagick on CentOS 6.3

I'm having a terrible time trying to get a recent version of ImageMagick installed on a CentOS 6.3 x86_64 server. First, I downloaded the RPM from the ImageMagick site and tried to install it. That ...
6
votes
1answer
3k views

How do I view the contents of a SELinux policy package

As the title says, how do I view the contents of a SELinux policy package? The resulting files end with .pp. I'm running on centos 6, but I guess it's the same way on "all" distros. For example ...
6
votes
4answers
6k views

File audit in Linux: how to watch directory tree for deletions?

I have a forum script running on server and somehow small number of attachments begin to get lost. I want to find out what is deleting them and at what time. How can I setup Linux auditd (auditctl) to ...
5
votes
2answers
8k views

iptables: forward port 80 to port 8080

How can I port-forward port 80 internally to port 8080? My goal is to have a web app server (Glassfish) running on port 8080, but for the outside world to access it normally on port 80. This is ...
3
votes
1answer
1k views

Cent OS upgrade PHP

I'm in the midst of resolving a bunch of security issues on a clients server to get them compliant with credit card laws and such. The first order of business is getting php from 5.2.14 to 5.2.16. ...
2
votes
3answers
256 views

Any good resources for setting up a webserver in Linux?

Are there any good resources (videos, ebooks, websites, etc) which allow you to self learn how to configure and manage: Securing a server Web Server (Apache, PHP, MySQL, Perl, TomCat, etc) Mail ...
11
votes
4answers
15k views

How do I change timezone in centos 6.2?

Here is the output of my date command: [root@r1304 ~]# date Wed Apr 18 15:43:28 GST 2012 I want to change the default system timezone to Asia/Dubai. I've fallowed a tutorial and did fallowing: ln ...