Questions tagged [linux]
Linux is the generic term for a UNIX-like open source operating system based on the Linux kernel.
38,415
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Performance problems when running Wireguard between Linux virtual machines. Same config on physical hosts works fine
I’m running into performance problems with Wireguard tunnels running between two virtual machines on the same hypervisor (running under Qemu/KVM) and I would greatly appreciate any insights/advice ...
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Simple solution to archive dovecot/postfix emails to second server nightly for long term storage with roundcube access
Our email server has ~150 email accounts containing material that cannot be deleted for 10 years. Some accounts are heading towards 10gb of data so I'd like to setup a nightly archive process that ...
- 41
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VPN on Linux - IP routing issue
I got the following scenario:
an ubuntu server 20.04 lts, for simplicity named A server with the following network interfaces:
loopback
enp1s0 (wan) PUBLIC-IP/23
enp8s0 (lan) 10.9.96.3/20
ppp0 (l2tp) ...
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Trigger OS shell script post kubernetes container boot
I am running truenas scale 23.01 with kubernetes. On the system I have a container X and a small app Y running natively that interacts with this container through its local IP and port.
Whenever ...
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Exim, Debian 12 (bookworm): Tainted '..Maildir/' (file or directory name for maildir_local_delivery transport) not permitted
I have this Exim transport that works just fine on Debian 10:
maildir_local_delivery:
driver = appendfile
group = mail
maildir_format = true
create_directory = true
directory = /home/${...
- 1,401
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1
answer
395
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Filtering for HTTP methods in IPv6 packets using tcpdump
I am using "tcpdump" to capture traffic, and I want to filter by HTTP methods. When I have IPv4 packets, I am using: tcpdump -s 0 -A 'tcp[((tcp[12:1] & 0xf0) >> 2):4] = 0x47455420' ...
- 51
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435
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Samba share not accessible to client in the same network
Two servers in the same network, a
Windows server (client), and a
Linux server (samba share host)
The shared folder can be seen by the client but not accessed. See below for the configuration:
smb....
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2
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457
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How to use nft on linux bridge to block access to certain ip addr?
I have an Ubuntu box with a bridge br0 defined. The bridge has eth0 connected to the internet service and eth1 connected to the network port of a PC. The bridge is functioning as expected and passing ...
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48
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Very strange behavior of OpenVPN between two sites
We've got a OpenVPN configured with layer2.
It is connected to a BGP router which announces a /24 IPv4 and a /29 IPv6. The purpose of the VPN is to redistribute IPv4 and IPv6.
However, recently I have ...
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42
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Systemd sequencial stop of template unit instances
I have a template unit that that I have to created in order to start/stop some services running an a given port. something like [email protected], se[email protected].
[Unit]
After=network.target
...
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1
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88
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Have you got a worked example of using Postgres through ODBC with openssl and the Progress DataDirect Linux driver?
I am new to openssl configuration, Postgres, and the Progress DataDirect ODBC driver, and I am trying to set this up. I have Postgres working in a container, set up with
tjcw:~$ openssl req -new -x509 ...
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Is it possible to configure a Linux/Ubuntu computer to be network silent?
I'm testing a customized network device using a Ubuntu computer from which I send network packets and check the actions on the network device. I'd like to only send over the packet I want, but since ...
- 3
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AWS CodeDeploy - Must be connected to a terminal
I have a CICD Bitbucket pipeline that runs and tries to execute a deployment script.
appspec.yml
version: 0.0
os: linux
files:
- source: scripts/osgi-deploy.sh
destination: /home/...
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SSL Certificate Renewal Broke Payment Gateway - Modulus Mismatch
I have encountered a problem with my website's SSL certificate renewal, and it seems to have affected my payment gateway. Here's a brief overview of the issue:
Background:
I have a payment gateway ...
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Reading from software RAID in parallel is slower than it "should" be, given other benchmarks
Note:
I have seen some somewhat similar questions here, but:
none of them concern reading many files in parallel, and
most are 10+ years old and concern no-longer-relevant hardware and kernel ...
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umount a bind source won't work, and device out of space
I think I may have shot myself in the foot. Long ago I tried to backup a old linux machine to a nas using the mount bind command:
mount --bind / /mnt/src
tar -C /mnt/src -c . > /mnt/backup_to_nas/...
- 139
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79
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Nftables does not work as expected to block with meter
Goal:
Account for excess packets whose rate source IP and destination port are greater than 200 packets per second, example:
1s to 2s:
IP 1.1.1.1 to MyServer:80
[This happens 201 times in second 1]
...
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1
answer
59
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Unable to Connect To Repo Server On Local Network
I currently have two VMs:
node1 (192.168.55.201)
repos (192.168.55.203)
I'm trying to set up node1 so that it can retrieve packages from the repo server. I currently have the AppStream repo, and ...
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Building server for research team
this is kind of a big task for me, I have an engineering background with computer science knowledge but I'm no expert in servers and networking.
I want to build a GPU-enabled computing platform that ...
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127
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TPROXY is not redirecting all traffic to a specified port
I'm writing a UDP transparent proxy in Rust, I'm using several crates
socket2 => Access to the creation of a RAW socket
nix::sys::socket => Access to all of the low level socket API calls
std::...
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50
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Possibility to handle HTTPS connections by retrying failed ones via proxy, solve occational "connect: connection refused"
Sometimes I receive this error:
Error: Get "https://example.com/etc/etc": dial tcp 10.0.0.1:443: connect: connection refused
The connection fails occasionally. When I try again, it works.
...
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Root user action constraints with sticky bit
I have an ubuntu 20.04.x instance on AWS which displayed very unexpected behaviour.
I have a file in /tmp:
root@ip-10-0-1-145:/tmp# ls -l api_requests_2023-08-23.log
-rw-r--r-- 1 www-data www-data ...
- 1,873
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68
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AD Domain joined linux server equivalent of NLA
First, some background.
Today, if you're in a mostly-Windows Server AD environment with just a small number of linux servers, you have a choice for authenticating to the servers via SSH:
Manage the ...
- 13k
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67
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Best Practices for Setting Up Multiple OpenVPN Instances for Different Clients
I'm working on a project where I need to set up OpenVPN instances to connect IoT devices from various customers to a central server. Each client should have its own isolated VPN connection. I'm ...
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62
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kafka kraft configuration + dedicated controllers machines
We are preparing Huge Kafka Kraft cluster
Installation is on 35 physical Linux machines and 3 dedicated controllers on 3 VM Linux machines
each broker machine include:
512G RAM memory
64 CORE's
...
- 559
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0
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86
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Prometheus Server Pod Suddenly Crashed (unexpected fault address 0x7f911b1795d4)
With traffic Prometheus server pod getting restarting with below error stack. This is happend when the live traffic of the system. But could not be able to reproduced with the load testing.
Grafana ...
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KVM: qemu-system-x86_64: cannot set up guest memory 'pc.ram': Cannot allocate memory
When trying to start a VM (1GB allocated) I have run into memory allocation issue even though I have more than enough memory on the system (16GB):
error: Failed to start domain exampleVM
error: ...
- 1,401
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125
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RHEL9.2 complains about missing /lib/modules/5.14.0-284.25.1.el9_2.x86_64 when rebuilding initramfs
The kernel on one of our RHEL9.2 servers was recently upgraded to 6.2.8 in preparation for a software upgrade but due to complications, we've had to revert back to 5.14.0-284.25.1.el9_2.x86_64.
I've ...
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1
answer
189
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Show quota limit of user's home directory
What I am trying to do is to get quota limit of current system user's home directory, which is btrfs quota-enabled, using the following command:
/usr/sbin/btrfs qgroup show-reF ~/
The above command ...
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NTP symmetric key authentication to chrony servers
Pretty simple question (I think), but in reading chrony's own docs and perusing through RedHat's docs, I can't find a firm answer. Probably because it's too dumb of a question to need an answer :P
If ...
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1
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207
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Tomcat Service failed
Hello I am trying to run the status of my Apache tomcat and I keep having it failed. this is what I am getting
tomcat.service - Tomcat 10 configuration file
Loaded: loaded (/etc/systemd/system/...
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2
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92
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wordpress directory file ownership changes everytime after uploading files/plugins
on centos 7, i have created wordpress website with root directory ownership websitename:websitegroup and directory permissions 755, file permissions 644 set by default
when the developer, login to ...
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1
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159
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ssh proxyjump command to config file
I use a ssh command for logging into a remote node using an intermediate node via proxyjump. The remote and intermediate nodes are Linux servers, and my client is a Macbook. This command works, and it ...
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How do I see the amount of bandwidth used during the execution of a program?
When executing a program, from a shell, how do I see the total amount of network bandwidth used by that program?
I am thinking of something similar to time, but for bandwidth.
petur@petur:~$ time ...
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0
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58
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DirectAdmin Apache/Nginx Reverse Proxy Custom Subdomain Config
I have a particular application on a subdomain that needs a custom Nginx configuration to work. I am using DirectAdmin control panel to make per-domain customisations. However, I am getting confused ...
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Make postfix retry PNCR Status (5xy code)
Every now and then I am forced to send medium volumes (100-1000 mails) to microsoft smtp servers (outlook.com/hotmail.com)
outlook-com.olc.protection.outlook.com
Remote Server returned '554 5.7.1 <...
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1
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147
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PHP Fatal Error: Cannot open /dev/urandom: No such file or directory when calling session_start() with manually built PHP
Problem
I built PHP8.4 manually in Ubuntu 14.04 since the OS is out of support with no ppa package available. I tested for phpinfo() web page showed correct information while adding session_start() at ...
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107
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I want to make Linux Kernel Source an RPM file
I am currently using Rocky Linux 8.7.
The current kernel version is "4.18.0-425.13.1.el8_7.x86_64".
I want to upgrade kernel through RPM, not source compile. In the kernel compile step, use ...
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DNSSEC - Unable to sign the relevant files
I have set up a working DNS server on an Ubuntu 22.04 LTS as part of a single server (DNS, SPF, Email, firewall etc)
IP: 192.168.122.189
Test Domain: jetj.ltd
Hostname:mail
The files I have are:
db....
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115
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VLANs and Bridges on Debian to share the same address
Right now I have a simple topology with the debian gateway, few managed switches and access points.
I'd like to add 3 VLANs to my topology and maybe use 802.1Q on debian gateway, so that all the ...
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122
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MYSQL use too much disk (read / write)
I have big problem with my server. I am using Ubuntu linux version 22.04. The problem is in the write / read disk (light for the disk is all the time ON) when I have turn on apache (PHP) and MYSQL. ...
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54
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Performance governor does not set the maxmum frequency
I am trying to use the governor on performance mode, but everytime I check the frequency values I see a frequency less than the CPU frequency. I am using a Intel(R) Xeon(R) CPU E5-2650 v4 @ 2.20GHz
$ ...
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1
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98
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Is it possible to disable ldap passwords for a user without disabling their account?
We have a cluster that uses an internal LDAP domain for user authentication that previously used passwords stored in LDAP. We have now moved the login machine to use krb5 for password authentication ...
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1
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88
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How to download binaries for MS ODBC18 Driver?
I need to install the MS ODBC 18 Driver into Amazon Linux 2 (for EC2). The steps here cannot be completed due to network restrictions: Microsoft ODBC 18. Also the package needs to be installed while ...
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1
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60
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How to append content of one file to another in Linux continuesly?
I have a log file log.log that is created by the application, I want to have any new line added to this file continuously being added to another log file historical_log.log. How can I do that? I am ...
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66
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Trying to set wake-on-lan persistently on linux fails
This is my box:
Linux mediacenter 5.15.122-1-MANJARO #1 SMP PREEMPT Tue Jul 25 07:09:46 UTC 2023 x86_64 GNU/Linux
I am trying to follow
https://wiki.archlinux.org/title/Wake-on-LAN
But I am failing to ...
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1
answer
48
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Shared server resouces mangement
We have an on-prem Xeon server running Ubuntu LTS that is shared across few developers. Each developer logs in with his on user and run various workloads on it. The problem we experience is when ...
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3
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603
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LVM: Creation difference between CentOS 7 and CentOS 6
I have CentOS 6 & 7 server and am creating 512 MB logical volumes:
CentOS 7:
sudo lvcreate -v -n lvname -L 512M rootvg && sudo mkfs.xfs -L "lvname" /dev/mapper/rootvg-lvnamee
...
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2
answers
132
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Lists active network ports and protocols over time
Is there a linux server utility that can list the network ports and protocols that have been active over a given period of time?
For example, I'd like to know which ports and protocols were active at ...
- 121
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2
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34
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Efficiently removing x-bit from files in large directory
I have a directory /some/dir containing millions of files and directories. I need to remove the X-bit for all file, but not from the directories.
The following works:
find /some/dir -type f -chmod -x {...
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