Newest linux Questions

Q&A for system and network administrators

systemd: Grant an unprivileged user permission to alter one specific service

I'm running a private game server on a headless linux box. Because I'm not an idiot, said server is running as its own unprivileged user with the bare minimum access rights it needs to download ...

Create zfs pool that allows replacing one of the disks with a slightly smaller disk

This is a quation regarding zfs on Linux (CentOS 7). I have a very simple setup with two 8 TB disks, one disk mirroring the other. zpool create -f -o ashift=12 $zpoolName mirror $disksById In case ...

File System on Linux: Set up for large Elasticsearch

I am setting up a single 750GB elasticsearch node (for logstash) on CentOS 6.8 Should I just set it up as a single large disk (boot and everything in one partition)? Or should I do the : /boot # ...

How to build an open source self healing network? [on hold]

I want to build a self-healing network for my School. I would like to have 1 server and a few clients they download the Windows image from the server and starting it. So after a restart, we have our ...

Linux Load Average in Billions with Thread Count Only in Thousands?

One of our servers is currently sitting with its load averages in the billions (with a b), while reporting that it only has 1,031 resident threads: top - 12:04:26 up 2 days, 19:03, 68 users, load ...

one script to monitor incoming ssh connections to the server

I want to make a script to monitor incoming ssh connections to the server. Try ForceCommand in sshd_config but it will not let me in if I put it there my script. Match User * X11Forwarding no ...

Linux install goes to blank screen [migrated]

I downloaded both latest Centos and Fedora ISO and burned onto CD using Imgburn. I then first booted up with Centos CD on my old HP DC5000 computer. It appears to boot to the CD just fine and gives me ...

Find out which process blocks my server

I have a VPS with some Docker containers running, and something strange happens about once a day: The server stops responding to anything (ping, cloud, ssh, mail, etc.) and when I go to the cloud ...

Where I config CNAME in VPS Server without Cpanel

I'm a newbie in linux/server configurations and I'm trying to redirect all subdomains of specific domain to specific url: *.domain.com -> domain.com/test With Cpanel visual support and CNAME I got ...

RAID10 - Clean, degraded - Missing disk

I just checked my Raid10 status and it says "Clean, degraded" Why is that? Isn't degraded a bad thing or something? I had 1 bad disk '/dev/sdd', so I replaced him and clicked "Recover" and it's ...

Supposed to have 256GB RAM, but system only shows 220GB

Have just added an extra Xeon quad core E5-2603v2 CPU to my HP DL360p Gen 8 and 16*16GB of ram. free -g however only shows 220GB: # free -g total used free shared ...

XEN HVM Windows install black screen?

So, I am running Xen.. i have a bunch of debian machines running no problem... release : 4.7.0-0.bpo.1-amd64 version : #1 SMP Debian 4.7.8-1~bpo8+1 (2016-10-19) I just ...

Immediately fix system clock after VMware stun

It's a known issue with VMware that it performs what is called a "stun" during certain operations, such as vmotion, and snapshot create/delete. During this stun, the guest OS is frozen, and so when it ...

Sendmail only sending locally

I wrote a script to send me an email if an existing process is not available, so I installed sendmail as suggested elsewhere. I know why I'm having the issue I'm having, but either I do not know how ...

Could reserved block count of zero hinder `fsck`?

I am considering setting the reserved block percentage to 0% (tune2fs -m 0 /dev/sdb1) for an ext4 partition. The partition is only used by non-privileged users anyway. Let's say I mistakenly fill up ...

Can't open port on Amazon EC2 instance

I have an API which I successfully hosted on Amazon AMI instance. I know that's for sure because I can use it locally using curl. Api hosted on port 8080. That's what I putted into cmd for open port: ...

logrotate when size reaches 10M

Please kindly advise/assist. I want to set up logrotate that does the following: when the log file size reaches 10M,the file is rotated and also there is no keeping of older compressed log files. I ...

Deny remote access to backup disk

I am trying to setup my own linux ftp/apache/ssh web server. The server is going have 2 drives. One for OS and one for backups. How can I deny any remote access to backup drive (even for admin if ...

Could this process bring down the server?

I'm trying to understand why a server (AWS Ubuntu) sometime becomes unresponsive and eventually has to be restarted. While looking through top logs, I found a process that I think might be causing ...

Why is shadowLastChange an unknown attr?

I'm trying to install slapd on Oracle Linux 7 and I'm following the Oracle® LinuxAdministrator's Guide for Release 7 section on Configuring an LDAP Server. When I get to step 7, importing the config ...

AIDE: match *.php files

Recently several sites got hacked and there was code injection and hacker scripts uploaded. What I wanted to do is use AIDE to track php file changes for all domains that are under /home. I can see ...

NFS mount via Round robin DNS only mounts from single system when using 10 Gb/s ethernet

We have a round-robin DNS setup that map the same name ("gsx") to six different IP addresses. This is verified as working from the client by using things such as 'nslookup' and 'ping'. However when ...

Securing CentOS traffic [closed]

@Moderators: First of all, please don't move this thread to already answered section. I want to encrypt traffic on my Linux system. All incoming and outgoing network traffic should be encrypted using ...

Telnet command windows to Linux server [migrated]

telnet from a windows PC to a Linux server and view the users that are logged on the telnet server?what command do you use to view users logged on....commands i found don't work

Authentication is required to manage system services or units.

I have a strange issue whenever trying to stop/start a daemon as a regular user, it asks to authenticate with the credentials of another regular user - for example: [bob@server ~]$ systemctl stop ...

Implementing PPPoE half-bridge/ip-passthrough to suit IPSec VPN firewall appliance with Linux

I'm stuck between a rock and a hard place: I have a VPN firewall from my corporate parent that must have a public IP and I have to connect it to the Internet using an ADSL modem (with static IP) in a ...

Apache Server is not reachable

Let me start by saying I'm not a sys admin but I've been tasked with creating a new apache web server. For now, I'm just trying to install the base package, confirm it's working and communicating on ...

Disable NTP server providing time sync to anonymous clients on the Internet

Have set up a Linux server (Debian 8.7) and is wondering how I prohibit anonymous clients on the Internet to use my server for time sync? Server has default ntp config - haven't touched anything yet. ...

apache2 won't start after ssl configuration

I did the following to make my websites https able (german): http://www.tecchannel.de/a/owncloud-9-unter-ubuntu-server-16-04-lts-installieren,3277807,2 now if I start apache2 I get this error : > ...

What exactly is Identity server and what is the purpose of using it

Currently I am working on a single sign on middleware application and I am confused with identity server and LDAP. I got to know LDAP is used for identity provisioning means it contains user records ...

Dedicated server CPU getting full when there is few users online [on hold]

I am developing a general knowledge website using PHP + Mysql which also have another option for mock test (objective type). There is more than 2 lakh questions and answers in the database. But when ...

How to create a qcow2 file that is not thin provisioned?

When I do the below then the qcow2 file is less than 200KB. # qemu-img create -f qcow2 /var/lib/libvirt/images/urb-dat0.qcow2 10G # du -hsc /var/lib/libvirt/images/urb-dat0.qcow2 196K /var/lib/...

What do i need to host a website from a computer from scratch [on hold]

So I am gathering parts together to build a server pc which will run Ubuntu Server. So what do I need to host a web server that people can type in my ip (temporarily to make sure it works) and get the ...

Bind DNS Problems to host a domain

I own a vps (Virtual Private Server) and have bind dns installed with apache, php5, and more through webmin. I want to configure a domain techmc.net for the on the Public web. How would I configure ...

Which KVM supported OS to use for latest fedora?

On the latest CentOS which is 7.3 right now, the latest supported fedora in KVM is fedora 23. If I want to have a Fedora 25 guest, which OS should I then say it is? Generic64?

Package upstream binary application for Debian

I am hosting an application which is available in the Internet in binary form. I am using Puppet for configuration management, but think that it is easier to package the application itself as a Debian ...

ARP request being sent to external IP addresses

I have an Ubuntu 16.04 machine. Here I create a virtual tunnel (tun) interface and make it the default route so that all traffic pass through it. I have a C application listening on this tun interface ...

Amazon EC2 CentOS Goes Down Every 5-7 Days [duplicate]

I have a strange behavior at one of my EC2 servers. It runs a basic LAMP stack and a Drupal site. The database of the site is small. From my understanding it should not cause any issues. However, ...

why can I not log in to this server?

I am trying to log in to a centos 6.8 server and I have the ip address and correct password. It stored the private key in my known_hosts file, but then I forgot about. My colleague can login from his ...

AutoSSL and WordPress Multisite, loading incorrect certificates [closed]

So this has been bothering me for weeks. We've got a WordPress Multisite installation, and with the push to SSL everything, we've taken advantage of cPanel's "AutoSSL" which I believe uses Let's ...

No connectivity between clients on the same interface

I'm having a problem configuring wireless interfaces in Linux. For some reason, traffic generated by wireless clients destined for other wireless clients on the same interface gets dropped (i.e. arp ...

crtc config fails when changing resolution with Xrandr from 4K

I am currently trying to change the resolution of my screen from 3840x2160 to 1920x1080. The screen is set to display 0 on output HDMI2. I am running an app via startx on display 0. When I try to run ...

FirewallD - Trusted Zones / Drop Zone and Tracerouting

Im using CentOS 7 and I have an issue where I am trying to lock down a server to only accept SSH from any private IP ranges of 10.0.0.0/8 which is in the work zone, and 10.0.20.0/24 for any connection ...

OpenVpn client can't reach internet via Openvpn server

I've issue on my Openvpn server where a client is unable to reach the internet via the server. Client can successfully connect to the Openvpn server and route is being pushed towards the server ...

Write arbitrary attribute into ENV from LDAP upon successful PAM authentication

Is it possible during the authentication phase of pam-ldap to map an arbitrary ldap attribute of the user's record into the resulting user's environment? The specifics of my situation, in case you ...

systemd timer fails to start (Invalid argument) when using UTC time

Here is my timer: [Unit] Description=Do whatever [Timer] OnCalendar=daily UTC [Install] WantedBy=timers.target It fails to start with the following error: Failed to start mytimer.timer: Unit ...

Openfire disconnected after sometime

I have setup openfire and it's working fine. Setup configuration are below 1) Openfire 4.1.0 2) Sever amazon 3) Database and Version MySQL 5.6.33 4) JDBC Driver Version mysql-connector-java-5.1.30 I ...

Block Postgres port 5432 running on Docker container with iptables

I am using Ubuntu 14.04 desktop (Xubuntu to be exact), and trying to block outside access to a locally running Postgres port 5432 with iptables. This is my iptables -S -A INPUT -i lo -p tcp -m tcp --...

Linux to Linux NFS UID change

I realized this has been asked before but unfortunately I don't have enough experience or enough time to continue crawling though the mountain of pages of search results that pop up for this. This is ...

How can I activate and use Nvidia Multi Process Service (MPS) with Slurm Workload Manager?

I have checked in the ./configure --help in the source code if there is a parameter that configures Nvidia Multi Process Service (MPS), but none exists, in addition, there is no option in sbatch that ...
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