Questions tagged [linux]
Linux is the generic term for a UNIX-like open source operating system based on the Linux kernel.
7,545
questions with no upvoted or accepted answers
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"Mount error 13" on CIFS connection w/o Domain Admin
Scenario
I have following clients in my network:
Quartz I2S scanner with embedded Linux firmware
Windows client (not domain-joined) for comparison
These will be trying to access a network share on ...
3
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0
answers
589
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New AWS Linux EC2 loses all networking about 7 minutes after bootup
I created a new AWS EC2 instance (error occurs with AWS Linux & AWS Linux 2). And I can SSH in fine to start installing thing but every time after 5-10 minutes I can no longer type in the terminal ...
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Sender address rejected: Access denied (in reply to RCPT TO command))
My email server has been ok for months now, since today my server would not receive any emails, I could send though. I seem to have fixed that by disabling and enabling UFW, not sure why that works ...
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3
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1
answer
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OpenVPN only works internal
I have set up a OpenVPN server according to this guide from DigitalOcean. But unfortunately I cannot get it working.
It seems like OpenVPN is just not receiving the network packets. I also tried ...
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3
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What do the numbers in square brackets of ethtool output mean?
I'm looking at NIC statistics and can't find any info about these numbers: [0],[1]..[7] like here:
[root@machine-1 ~]# ethtool -S enp21s0f0
NIC statistics:
[0]: rx_bytes: 23048043995115
[0]:...
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3
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Matrix Synapse matrix-appservice-irc messages only travel from IRC to Matrix
My irc bridge has connected the rooms i wanted, except messages are only passed from irc to matrix! Also the matrix[m] users are not appearing in the irc chatroom.
Here are my configs:
$ cat config....
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3
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1
answer
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Mysql cannot start - Could not find valid tablespace file for
My mysql service is currently unable to start with the error
InnoDB: Could not find a valid tablespace file for 'wowcher/temp_import'.
I think I know what the issue is. I have a PHP script which ...
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3
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1
answer
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Why does the 'nomatch' option of ipset not work in this case?
I am using ipset 6.23-2 on Debian Jessie. I created a hash:net set for and an iptables rule to drop all traffic for addresses in the set.
Chain INPUT (policy ACCEPT)
target prot opt source ...
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3
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1
answer
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VMware: any way to take snapshot from client os?
I am running ESXI 6 with a Linux VM. VMWare tools are installed on the client os. Is there any way to trigger a snapshot from within the client os? Without accessing the host directly?
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How to connect to ikev2 vpn from docker container using bridge net mode?
I'm trying to connect to a VPN from inside a docker container via ikev2, Ubuntu host.
If I try the following:
docker run -i -t --privileged --net host --entrypoint /bin/bash ikev
It then do ipsec ...
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Red Hat kernel says "Clocksource tsc unstable" but I'm using kvm-clock
I have a couple of virtualized RHEL 6 running on a RHEV host. Both host and VMs have >1year uptime.
Only in the last two days they started seldom throwing these kernel messages at random times
...
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Missing WSMan provider on PowerShell Linux (to use remoting)
I'm trying to remote PowerShell from Linux to a Windows Nano Server on Azure.
There's a part in the instructions where I add the IP of the remote server to local computer's trusted hosts:
PS > ...
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3
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Reaching maximum TIME_WAIT sockets (tried tcp_fin_timeout)
tl;dr: How do i get the kernel to drop TIME_WAIT/closing sockets as forcibly and fast as possible? I don't care about data being lost since I'm not sending any.
I'm currently running a little test ...
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Network UPS Tools (NUT) causing UPS to Reboot?
I have NUT upsmon 2.7.2 installed on an OrangePi One running Armbian 5.25 (which is Debian jessie). It is setup to monitor my Tripp Lite SmartOnline SU3000RTXLCS2U using the usbhid-ups driver and ...
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The strangest docker fault I've ever seen
I am using Docker with docker-mailserver on one of my servers. Very strange trouble appeared after migrating some services from legacy Debian Jessie server to Ubuntu 16.04 LTS server. Parameters of ...
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1
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Redis not starting on boot
I have installed the redis-server package on Ubuntu 14.04 LTS, running in Amazon EC2.
ii redis-server 2:2.8.4-2 amd64
ii redis-tools 2:2.8.4-2 amd64
It didn't start on boot. So I ran the ...
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505
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Any limit on initcwnd?
We are trying to decrease the initial latency on TCP connections to our servers. In some test we found that when we download a file below 15587 bytes the total downloading time (apache benchmark total)...
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3
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1
answer
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Best deployment and configuration tool for servers with limited internet connection
I am looking for the best available option for a Linux server deployment and configuration management. Unfortunately this is not a typical scenario with servers placed in a data center. Instead we ...
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3
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1
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packets transmitted, 0 received (no internet connection) on centos 6.6 vps
I have centos 6.6 vps server.
When I use command: yum update get error:
Error: Cannot find a valid baseurl for repo: base
when I check for ping and use command: ping -c4 google.com get error:
ping: ...
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3
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2
answers
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Use Logrotate to truncate log files after every entry or clear last 'n' entries
i have created a logrotate config file:
touch /etc/logrotate.d/.test
with the conficurations:
/home/myUser/test*.log{
size 0
hourly
rotate 0
nocreate
nocompress
...
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3
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1
answer
532
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iptables block IP for x hours not working?
On my Linux server, I want to ban IPs that access certain ports for 24 hours using IPtables. For this, I use the following IPtables rules:
# Check if IP is on banlist, if yes then drop
-A INPUT -m ...
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answers
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OpenVSwitch with Libvirt
Here's my situation: I'm running CentOS 7 with Openvswitch and Libvirt/Qemu. My domains are configured to use the virtualport type openvswitch, so when I start a VM it creates a port in the ovs bridge....
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3
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Is it possible to limit the number of previous users on login screen in centos?
I'd like to customize the login screen on CentOS to limit the number of users displayed? I know how to disable the user's list by customizing the dconf gdm db but I wonder if I can set a limit value......
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3
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Programatically (with syscall) invalidate NFS lookupcache
I have a process that relies on detecting file creation on an NFS server.
Usually it works fine, but there's been a few minor glitches recently, due to caching and an NFS rename operation.
We've ...
- 3,767
3
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fstrim vs. mount -o discard: How come discard.... doesn't?
I've noticed from time-to-time that running fstrim on mounted ext4 filesystems yields massive amounts of trimmed space even when these filesystems are mounted with the discard option. I thought the ...
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3
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1
answer
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Server closed connection error when checking if key exists in a redis cluster using stunnel
Using redis-cli command line utility with the -c switch to connect to a redis cluster with stunnel configured and running.
When I execute the EXISTS command to verify a key, as expected, it redirects ...
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Ubuntu 16.04 Systemd not possible to use systemctl
I have a Ubuntu 16.04 server, since the last restart,
systemctl doesn't work anymore.
For example if I want to start the nginx, I get the following error:
root@SERVER:/# systemctl start nginx
...
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3
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why my XFS file system got corrupted? root cause analysis
I have a block SAN storage volume mounted to my server via FC, I have formatted the volume with XFS.
I started experiencing file system corruption that can be easily repaired with xfs_repair, ...
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3
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SSH fork of unprivileged child failed on connection
we have some problem when we try to make an ssh connection to our server.
When we connect with user X (ssh x@serverIP) we receive these errors on console:
Connection to serverIP closed by remote ...
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3
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1
answer
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How to set DSCP values for outgoing traffic from my linux server to check whether QOS is working correctly or not?
I have to validate whether my router's QOS policies are working correctly.I have come up with an approach to tag the packets with DSCP values using IPTABLES.
Can anyone confirm whether my approach is ...
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LVM: failed logical volume removing from VG after disk was detached
The old storage device for backup was upgraded to new one.
An old storage device was unmounted and detached from server, but NOT removed from LVM.
This backup device was in separated VG and LV.
I ...
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3
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1
answer
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EDAC memory error after upgrade server SuperMicro with CentOS 7. Is these specific errors of motherboard, OS or broken RAM module?
I have server on SuperMicro MBD-X9DRD-EF motherboard. It worked well at CentOS7 during the year with one CPU (Intel Original Xeon X6 E5-2620v2) and 128 Gb (8x16 Gb) LVDDR (1600MHz Crucial ECC Reg RTL (...
3
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Create mdraid with multipath disks in in RHEL7:
I am still novice in the world of storage. I am working on a project of migrating our backups infra from Solaris to Linux.
As part of that, I have rebuilt a server to Linux (RHEL7) and it has 2 root ...
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How to get x86_energy_perf_policy // linux-tools-* for Linux kernel 4.7.0-xyz
I am using pstate-frequency to set our server cpu's frequency. This tool needs the x86_energy_perf_policy which is provided by the linux-tools-common package.
Using the distributions standard kernel ...
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3
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Cannot balance eth0 IRQs across CPUs
I have servers which deal with a large number of network packets. I've seen evidence that user space processes running on CPU0 have their performance impacted when network load is high. I'm fairly ...
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3
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1
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In docker, what are these POSTROUTING iptables rules for?
Docker creates a MASQUERADE iptables rule for every container that has an exposed port (in this example I have 5 containers with exposed port 3500):
sudo iptables -t nat -L -v -n
<snip>
Chain ...
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493
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How to trigger initial login so user slice gets created
I may be taking the wrong approach here, but the new centos 7 implementation of cgroups lets you put limits on user's access to system resources by attaching said limits to their slices.
Ie.
...
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Can't bind UDP socket but port is free
I've been struggling for a while now with this so maybe someone here is able to help me.
I'm setting up a CS:GO server that's going to be running on port 27059.
(This is a copy&paste from a ...
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policy routing for local outcoming connections
I have a multihomed setup with two upstream providers. And I want to confine some connections to use only one provider — local outgoing connections that is. So, I've made a custom routing table, which ...
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Multiple Nginx Error Log Locations
I'm trying to get Nginx to log both in a log file and to stderr. The reasoning behind this is that I want Nginx to log to a log file as well as to journald. From the research and tests I've done I ...
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How to verify network quality before running important benchmarks?
I have multiple CentOS servers around the world. They all are running a PHP script that tests the latency of some services once per minute.
The problem is that sometimes these servers have local ...
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Can't find users logged in with notty via the who command
I was curious if anyone had any ideas why when I run who and who --all, I still cannot see users logged in under notty?
See below:
[cbennett@lstn ~]$ who --all
system boot 2016-04-25 09:...
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ifconfig output different for non-root user
we use a montoring system to capture network traffic. the output as root user is fine:
eth0 Link encap:Ethernet HWaddr 00:1E:67:E6:D6:FE
inet addr:149.56.19.13 Bcast:149.56.19.255 ...
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Is it possible to use Active directory without a trust relationship for FreeIPA passwords?
I am looking to integrate FreeIPA with an Active Directory environment that I do not have full control over and most likely will not be able to get a trust relationship setup with my FreeIPA install.
...
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How to change server time safely for testing purposes
We have a Debian server (in a VM) running a Java application on a Tomcat server, using a Postgres database. It's a testing environment, so we can do anything we want to it.
Every once in a while, we ...
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How to configure RealVNC to use dual displays full screen
The setup is the following:
VMWare ESXi5.0 Virtualisation server running a virtual machine Win7. This virtual machine is configured to have 2x Generic Non-PNP displays both at 1920x1200 resolution. ...
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3
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2
answers
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Cannot ping through one of the network interfaces
Setup
ubuntu linux VM ( virtual-box) is configured with two interfaces, eth0 and eth1.
eth0 is on a bridged network and directly connected to external network.
eth1 is on "nat network", which is ...
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3
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4k
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Can I Intentionally Disable PCIe Lanes? Or lower PCIe Width?
I am doing some testing on my server and want to lower the width to my PCIe device (or its PCIe bridge).
In case it is relevant, I figured out how to lower my speed based on the PCI Spec with Linux'...
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answers
560
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Adding mfa verification code to ssh command?
Im trying automate the login process using shell script.
I got MFA + pub key authentication working.
However Im stuck at how to pass verfication code as a parameter to ssh command.
I tried go ...
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203
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can identify and authenticate an ldap user in one of two distinct, separate domains?
Most people configure PAM and NSS ldap modules to point to ldap servers that handles a single search base as defined in pam_ldap.conf or libnss-ldap.conf. The man pages do not describe any option to ...
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