Red Hat Enterprise Linux version 6 is a Linux distribution sold by Red Hat, Inc. for the enterprise market. It is used for both servers and desktops. Although the binaries are not freely available, the sources are, and so there are numerous projects which provide compatible rebuilds of RHEL, such as ...

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94
votes
6answers
197k views

What version of RHEL am I using?

From the shell and without root privileges, how can I determine what Red Hat Enterprise Linux version I'm running? Ideally, I'd like to get both the major and minor release version, for example RHEL ...
90
votes
2answers
45k views

IPTABLES - Limit rate of a specific incoming IP

I do not wish to limit the rate of a specific service. My goals is to limit rate based solely on the incoming IP address. For example using a pseudo-rule: john.domain.local (192.168.1.100) can only ...
26
votes
3answers
37k views

Human readable format for http headers with tcpdump

I would like to view the HTTP headers sent from Apache (listening on port 80) to Tomcat (on port 4080) in a Linux machine. According to Wikipedia, Header fields are colon-separated name-value ...
14
votes
2answers
3k views

HP DL380p Gen8 (p420i controller) I/O oddity on XFS partitions

On DL380p gen8 servers using XFS on top of LVM on top of raid 1+0 with 6 disks, an identical workload results in a ten-fold increase in disk writes on RHEL 6 compared to RHEL 5, making applications ...
13
votes
2answers
6k views

Persist IP address alias across reboots in CentOS/RHEL 6 using “ip” command

I've always used the ifcfg-eth0:1 alias files to create additional addresses. However, in recent rhel documentation, it states that: As the ip command of the iproute package now supports assigning ...
13
votes
2answers
14k views

Do I need a RHEL subscription to install packages?

I'm new to RHEL. Trying to install software this morning and running into road blocks. Is it required to have a subscription to download packages via yum on RHEL? I'm coming across different sources ...
13
votes
2answers
39k views

Upgrade CentOS 5.x to CentOS 6.x - tips and techniques

Now that CentOS 6.0 is making its way to the various mirror sites, I wanted to solicit opinions on the upgrade process. In working with the commercial RedHat 5.6 and 6.x distributions for the past few ...
12
votes
3answers
11k views

How to free up space on RHEL6 /boot safely?

I am trying to do yum update on RHEL 6 box and I am getting this error message Transaction Check Error: installing package kernel-2.6.32-279.9.1.el6.x86_64 needs 10MB on the /boot filesystem ...
12
votes
2answers
9k views

Anything Close to an NSA Guide for Securing RHEL 6 [closed]

Some in our infrastructure group want to upgrade to start taking advantage of the new features in RHEL 6. In the past, I have relied on the NSA Guide (www.nsa.gov/ia/_files/os/redhat/rhel5-guide-i731....
10
votes
3answers
12k views

RHEL 6.4: Mode 1 channel bonding not failing over

I'm running RHEL 6.4, kernel-2.6.32-358.el6.i686, on an HP ML 350 G5 with two onboard Broadcom NetXtreme II BCM5708 1000Base-T NICs. My goal is to channel bond the two interfaces into a mode=1 ...
10
votes
3answers
1k views

RedHat: is it possible to install packages in a kind of mock environment to build RPMs

Is there a tool that allows to install the dependecies of an RPM .spec into an isolated environment? I won't install such dependencies globally on the system and I am not able to do so since I have ...
9
votes
2answers
4k views

How do I make a persistent domain with virsh?

virsh create somefile.xml creates my machine just fine but when I shut the machine down the whole thing disappears. Machines I made with the virt-manager GUI are persistent (stick around after ...
9
votes
2answers
4k views

What in a kickstart file sets the desktop GUI as default (runlevel 5)?

I am using Scientific Linux 6 and am installing the following desktop-related package groups: @basic-desktop @desktop-platform @general-desktop @x11 However, after installation, /etc/inittab still ...
9
votes
2answers
22k views

How can I install git on RHEL 6?

I'm trying to install Git on a RHEL6 development server, I have experience with Ubuntu but this is my first time working with RHEL (I'm a developer trying to fill in for a recently departed Linux ...
8
votes
2answers
2k views

What is the yum equivalent of dpkg -L?

dpkg -L lists all the files provided by a package. How is this accomplished with yum? The operating system is Scientific Linux 6.
8
votes
1answer
9k views

“power limit notification” clobbering on 12G Dell servers with RHEL6

Server: Poweredge r620 OS: RHEL 6.4 Kernel: 2.6.32-358.18.1.el6.x86_64 I'm experiencing application alarms in my production environment. Critical CPU hungry processes are being starved of resources ...
7
votes
3answers
12k views

What is the relation between NetworkManager and network service in Fedora/RHEL/Centos?

Hi I am new to Fedora/Centos/RHEL. I am confused about NetworkManager and network service in these Linux OS. May I know what is the relation between NetworkManager and network service? If I am using ...
7
votes
4answers
15k views

Can I set up Fedora or Centos repos in RHEL6?

I have a RHEL6 box with no subscription to Red Hat Network. I want to install gcc using yum to resolve all the complex dependencies. Can I connect to Fedora or Centos repositories to install software? ...
7
votes
2answers
7k views

What are the disadvantages of disabling tinker panic 0 in NTP?

We sometimes have the problem that new servers have the wrong time in the bios, so there time can be off by a month. When you suspend a VM in VMware and then unsuspend it, the time will be off too. ...
7
votes
3answers
5k views

How to make NTP work despite a high offset?

Recently I have kickstarted some servers that had their time off by a month in the bios. The time in the bios said it was a random time/date in May, while it was June. This caused NTP not to work, ...
7
votes
1answer
920 views

How can I use SELinux to confine PHP scripts?

I want to compartmentalize different PHP applications on my SL6.4 (RHEL 6.4 rebuild) web server so that they cannot access each others' data. It seems that SELinux might be able to do this, but I am ...
7
votes
2answers
474 views

SSSD rejects LDAP login with su: incorrect password

I've set up an LDAP server with user accounts. I've successfully configured a Rails application to authenticate against this LDAP server. I'm now trying to configure SSSD to authenticate against LDAP, ...
7
votes
3answers
4k views

Php pdo_dblib - cannot find/unable to load freetds

Self-hosted box, RHEL 6 PHP 5.3.3 PDO installed freetds installed pdo_dblib - so far no luck installing My goal is to use PDO with sybase. Attempting to install pdo_dblib from the appropriate ...
6
votes
3answers
10k views

Understanding RedHat's recommended tuned profiles

We are going to roll out tuned (and numad) on ~1000 servers, the majority of them being VMware servers either on NetApp or 3Par storage. According to RedHats documentation we should choose the ...
6
votes
3answers
14k views

How come all LDAP users are shown with getent passwd?

We are using an LDAP server with both Solaris and RHEL servers and planning to migrate more servers over to RHEL. However we have an issue with LDAP on all Red Hat servers. When I type "getent ...
6
votes
1answer
181 views

RHEL6 Keeping 1 old kernel and security

I have my RHEL 5&6 servers set to keep 1 old kernel after updates, I do this in case I need to recover the system for any number of reasons. My question is related to security of the system when ...
6
votes
2answers
17k views

Account Lockout with pam_tally2 in RHEL6

I am using pam_tally2 to lockout accounts after 3 failed logins per policy, however, the connecting user does not receive the error indicating pam_tally2's action. (Via SSH.) I expect to see on the ...
6
votes
2answers
4k views

Ansible Fails to Authenticate Sudo Even When Sudo Pass is Given

Problem Using the latest, stable Ansible build, I have an odd problem where my playbook hangs on one server during "Gathering_Facts" but works fine on other similar servers when using Sudo. On the ...
5
votes
6answers
2k views

Reloading a kernel “live” in CentOS / RHEL 6

When upgrading the kernel package on CentOS or RHEL 6, is it possible to load the new kernel without rebooting? My gut tells me it's not, but if it were, it'd be handy - especially when compiling ...
5
votes
2answers
472 views

CentOS 6 in production

All of my virtual servers are on Centos 5.5. Now I am deploying new one and there is a new OS option: CentOS 6. I like new software, and I prefer to use new versions (but not the edge). So, as far as ...
5
votes
2answers
2k views

Is PHP 5.3.3 on RHEL 6.5 receiving security fixes?

I notice that the latest PHP available on RHEL 6.5 is PHP 5.3.3. See Distrowatch and also my own check: $ php -v PHP 5.3.3 (cli) (built: Jul 15 2014 08:48:08) However, the PHP website claims that ...
5
votes
5answers
47k views

How do I install the main repositories for RHEL6

We've setup RHEL6 on a new server. As far as we can tell, our subscription is all setup properly. However, when I run yum repolist, it doesn't show any repositories. /etc/yum.repos.d/redhat.repo is ...
5
votes
3answers
4k views

Anaconda kickstart and rootpw option

I've tried a few different methods of generating an encrypted password on SL 6.5, but nothing seems to work for me. I'm not finding any errors anywhere in the various /var/log/anaconda* files, but I ...
5
votes
2answers
10k views

Generating an SHA256 SSL CSR on CentOS/RHEL using genkey

The officially recommended method of generating a web server SSL certificate CSR (according to RHEL6 and CentOS 6 documentation) is to use the genkey utility. When used according to the docs, this ...
5
votes
2answers
3k views

How to kill ostensibly immortal process?

I had some huge file transfers operating on an NFS mount. The server on which the mount point resided was carelessly rebooted, and now the server from which these large transfers were initiated seems ...
5
votes
2answers
2k views

Modify XFS filesystem creation parameters during kickstart installation

I'm streamlining the kickstart process for a series of EL6.2 (RHEL, CentOS, SL, etc.) systems. I'd prefer to use XFS over ext4 for the growth/data partition. However, I'd like some control over the ...
5
votes
2answers
6k views

Why is Linux kdump not writing to /var/crash?

It's happened again! I have 4 servers which are crashing periodically, and there is no information printed to the system logs or the serial console. In addition, the Linux kdump service isn't writing ...
5
votes
3answers
6k views

Interpreting cryptic kernel “page allocation failure” messages

I have a multi-user CentOS 6.1 database system running an application named ABC. The server is 64-bit, 8GB RAM and 6 vCPU (on VMWare ESXi 4). We get frequent dumps into the dmesg and the system logs ...
5
votes
1answer
7k views

How to upgrade module located inside initramfs?

We have recently upgraded our e1000e (intel ethernet) module on one of our CentOS 6.0 boxes. Even tho the module compile and installed fine, the old version is still being used. We have tracked this ...
5
votes
1answer
4k views

Are Link-Local routes necessary (IPv4)?

I noticed in my routes output in RHEL6 (and most 2.6.x series Linux), for every interface I see the creation of the following route in my kernel routing table: 169.254.0.0 0.0.0.0 255.255....
5
votes
2answers
830 views

apache/httpd responds slower under EL6.1 than EL5.6 (CentOS)

I've read through other threads on performance differences between RHEL 6 and RHEL 5, but none seem a tight match to mine. My issue manifests itself in slightly slower average response time (20ms) ...
4
votes
4answers
24k views

RHEL 6 x64: running 32 bit applications

We develop an application which currently works in 32 bit mode only. It worked fine in RHEL 5 but failed to work in RHEL 6. The reason is RHEL 6 by default is installed with 64 bit libraries only. ...
4
votes
5answers
2k views

Reboot fails on RHEL 6.1 after kernel update on Amazon EC2

Everytime I start a new RHEL instance, I like to perform a yum update to start with the most up-to-date system. However, everytime I try to reboot the instance after that, the instance never goes ...
4
votes
5answers
700 views

Degraded httpd performance after moving from RHEL 5.6 to 6.1

We have recently replaced an RHEL 5.6 web server with RHEL 6.1. For both environments, the (stock) Redhat shipped Apache httpd has been used (i.e. yum install httpd). The server is serving PHP ...
4
votes
2answers
3k views

SL6: Non-standard home directories, Error: `Could not chdir to home directory` upon login, but `cd $HOME` works?

I have a brand new Scientific Linux 6 instance (Similar to RHEL6 & CentOS6), running on Parallels. The home directory is in a non-standard location, which I'll call /homedir When I ssh into this ...
4
votes
4answers
4k views

PHP Startup: Unable to load dynamic library '/usr/lib64/php/modules/gd.so' undefined symbol: gdImageWebpCtx in Unknown

We're running RHEL6 and just started getting this error when restarting php-fpm. PHP Startup: Unable to load dynamic library '/usr/lib64/php/modules/gd.so' - /usr/lib64/php/modules/gd.so: ...
4
votes
2answers
3k views

Errors using new rsyslog template syntax on RHEL6

I'm migrating our rsyslog config from an old server to a new one, and thought I'd use the opportunity to tidy up our config. The old config used "legacy" template definitions, and the rsyslog doc on ...
4
votes
2answers
12k views

Clone kvm/qemu VM to a different server

What's the easiest/quickest way to clone a VM from one server onto another if you don't have shared storage between the two servers (so you can't do a standard migration)? I have a production ready ...
4
votes
1answer
13k views

RHEL 6.2 hangs at startup screen after forced reboot

I had to force a hardware reboot due to some CPU hungry application. It now hangs at the start-up screen right after the progress circle completes. I have no way to see what it is doing (checking the ...
4
votes
5answers
3k views

Server freezes while installing Redhat Enterprise Linux Server 6

We've tried both the first options Install or upgrade an existing system Install system with basic video driver When trying option #1, it gets to a screen that has a solid cursor about halfway ...