40
votes
Accepted
How do I use Linux to find unused IP addresses on my network?
Any well-behaved device on an Ethernet LAN is free to ignore nearly any traffic, so PINGs, port scans, and the like are all unreliable. Devices are not, however, free to ignore ARP requests, afaik. ...
- 81k
28
votes
20
votes
How do I use Linux to find unused IP addresses on my network?
Since a device cannot ignore ARP requests, I like to use a tool named arp-scan. It is available in most repositories.
When you run the command with the --localnet switch it will give you an overview ...
- 1,441
19
votes
Do I need a RHEL subscription to install packages?
An alternative is to add the CentOS repository to your yum configs. CentOS is in large part a derivative of RHEL. As such, most of its packages are compatible with RHEL.
Michael Cutler wrote a guide ...
- 293
12
votes
Accepted
SSH Local Port forwarding working from localhost only
Are you aware that you type 4122 in the example?
You should try
-L *:4420:172.88.3.31:22
The star implies that you listen on all addresses, and not localhost, which you cannot connect to from ...
- 303
11
votes
How do I use Linux to find unused IP addresses on my network?
I don't know which version of nmap you are running in your Red Hat 6.5, but for recent releases, the correct (and faster) way I think it would be:
nmap -sn -n 172.16.128.0/25
This will list every ...
- 1,943
8
votes
How do I use Linux to find unused IP addresses on my network?
Part 1 -- fping
This tool pings everything in the network range specified, and shows those that answer via ICMP.
root@thionite:~# fping -a -g 10.28.1.0/24
10.28.1.1
10.28.1.2
10.28.1.3
10.28.1.4
10....
- 2,330
8
votes
Accepted
It should be set to 65000 to avoid operational disruption
You set the hard limits, but not the soft limits, and the soft limits are what is being reported. You should also set the soft limits, in the same way.
solr soft nofile 65000
solr soft ...
- 250k
7
votes
How to build curl for TLSv1.2 support?
You should not need to build your own curl version, support for TLS 1.1 & 1.2 (with the --tlsv1.1 resp. --tlsv1.2 commandline switches)
has been backported and became available in 2014 from curl ...
- 81.6k
7
votes
Accepted
mount.cifs: mount error(112): Host is down
I found this link here which says SMB 2 and 3 is not supported for rhel and Centos 6. It can only mount SMB1. From Centos and rhel 7 this is supported.
- 409
6
votes
Accepted
what are public yum respositories for red hat linux
Red Hat requires a subscription to make use of their repositories, meaning you need to join their developer program or pay for a subscription.
If you don't actually need Red Hat specifically (or a ...
- 206
5
votes
completely remove phpmyadmin centos
You do realise that locate looks at a database cache with filenames (created nightly/manually with the updatedb command) and not at your live file system.
locate does not reflect the actual state of ...
- 81.6k
5
votes
Accepted
File Copy failing using Puppet File resource
Your module(s) don't appear to conform to the standard directory structure. With a source URL of puppet:///modules/foo/bar.txt, Puppet will be looking for ${codedir}/environments/production/modules/...
- 4,811
5
votes
Almost every app (rpm,curl..) is broken (Red Hat Enterprise Linux 6.8) after rpm force installation - libnssutil3.so error
The non-sarcasting and reliable answer would be this.
That script downloaded all dependencies, including a bunch of system libraries. The version of Fedora you used and RHEL 6 are NOT binary ...
- 7,227
5
votes
How do I use Linux to find unused IP addresses on my network?
IPv6
Don't assume that IPv4 is your only option. Many modern operating systems handle IPv6 just fine, even if your ISP doesn't provide V6 connectivity.
There may even be devices which are only ...
- 2,330
4
votes
Accepted
Creating multiple directories using puppet
Remove the quotation marks from the resource title, and the unnecessary path parameter:
file { $appdirs:
ensure => directory,
owner => root,
group => root,
mode => 0644,
}
...
- 3,170
4
votes
Accepted
Opening a firewall port in RHEL 6.8
It looks like your /etc/sysconfig/iptables config file is getting overwritten by /opt/ibm/c4eb/firewall/create-rule-file.sh (see the last bit of your iptables config file) ...
FILE=`mktemp -q /tmp/...
- 4,567
4
votes
How do I use Linux to find unused IP addresses on my network?
In addition to MadHatter's answer, there is a tool does the arp lookup without trying to send a network packet first: arping.
There seem to be two implementations:
arping (Thomas Habets version).
...
- 1,743
3
votes
3
votes
Accepted
Migrating Puppet Code to Puppet 4: Issue with Classes
You've not included all of your subversion.pp but it looks like you have something like the following:
exec { 'sh /home/agile/svncheckout.sh':
unless => 'test -f /home/agile/subversion.done',
....
- 4,811
3
votes
Accepted
Migrating to Puppet 4.5.2
If I am not wrong then I can copy all manifests under classes and nodes directory to the below manifest directory
Yes, the manifest directory will be imported recursively, so this is the best thing ...
- 3,170
3
votes
Accepted
Can I filter output from `tail` with the `-f` flag?
I just did a tail -f <nginx-access.log> | grep <ip> and as expected new lines showed up regularly.
What happens when you try? Could it be hat your grep buffers (I think i've seen that), ...
3
votes
What version of RHEL am I using?
I prefer hostnamectl:
$ hostnamectl
Static hostname: xxxxxx.xxx.xxx
Icon name: computer-server
Chassis: server
Machine ID: 3e3038756eaf4c5c954ec3d24f35b13f
...
3
votes
What version of RHEL am I using?
I quite like using the /etc/os-release file, which is in the release RPM:
# yum whatprovides /etc/os-release
Loaded plugins: fastestmirror, langpacks
Determining fastest mirrors
* base: dl.za....
- 504
3
votes
what are public yum respositories for red hat linux
You can install CentOS repos, if you don't have subscription to Red Hat.
See this link on migrating from RedHat packages to CentOS packages.
https://wiki.centos.org/HowTos/MigrationGuide
From the ...
- 2,811
3
votes
Puppet File resource :"Parent Directory does not exist" error
file { '/data/tomcat/$dirsname/conf':
Replace the single quotes with double quotes, then the variable will be interpolated. Do this on all lines with single quotes and variables (there are four).
As ...
- 3,170
3
votes
Accepted
Puppetserver not coming up after fresh installation
It looks like you are trying to run the puppetmaster using Java 6, and it needs a more recent version. Install a newer version of java ( yum install java-1.8.0-openjdk-headless ) and try again.
- 300
3
votes
Accepted
Multiple site.pp for the same nodes
Puppet is not supposed to have multiples site.pp
If your goal is to apply manually one of your configuration, you can use the --tags option. By the way, you should configure your agent to act as noop ...
- 762
3
votes
Accepted
Only allow root to do su specific user
Well, once you allow a user to become root, short of using SELinux there's no way to restrict them. Which is why you shouldn't hand out root permissions willy-nilly.
I'd recommend moving away from su ...
- 9,829
3
votes
SSH Local Port forwarding working from localhost only
Martin's answer should work.
-L *:4420:172.88.3.31:22
or -L 0.0.0.0:4420:172.88.3.31:22
or -L [specific IP]:4420:172.88.3.31:22
Another way:
-L -g 4420:172.88.3.31:22
Referenced from man ssh
-g ...
- 31
Only top scored, non community-wiki answers of a minimum length are eligible