Questions tagged [troubleshooting]
Troubleshooting is a form of problem solving, often applied to repair failed products or processes.
359
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How to fix a corrupt server (after upgrade) with chroot in rescue-mode over ssh
First, I'm NOT trying to create a ssh-jail.
Here's the situation
I decided to upgrade my server from Debian 9 to 12. But now I'm locked out.
I went step by step : from 9 to 10, 10 to 11 and 11 to 12, ...
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38
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Forcing freeradius to use 802.1x-2010
I am trying to troubleshoot a remote problem, where a piece of hardware is unable to connect using enterprise WPA. From the remote logs, it seems that the network is using 802.1X-2010, while the ...
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184
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Linux Server is slow on running some commands
I have a Linux server and ubuntu 20.04 is installed on it. Kernel version is 5.4.0-163-generic. 24 cores and 32GB RAM.
I have database running on this server which is working without any issue. ...
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363
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ICSharpCode.sharpziplib.zip.zipexception. Cannot find central directory
Every time we run a certain commercial software in a Windows Server 2019 we get a pop-up window with this error:
ICSharpCode.sharpziplib.zip.zipexception. Cannot find central directory
It looks like ...
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63
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Double Nginx installation issue
It seems i somehow have two installations of Nginx on a server, Nginx Amplify reports two installations (see screenshot), one of them not sending updates of course, and occasionally when restarting ...
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1
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58
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Troubleshooting K8 cluster with StatefulSets that don't respond to scales
I currently have a Kubernetes environment which is generally not behaving (slow response times to commands, pods not being scheduled, etc).
I've not been able to find any trouble shooting information ...
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72
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How to figure out what makes a Linux workstation slow?
We have this ThinkPad X240, 8GiB of RAM, an i5 4300U, and a Toshiba SATA SSD. The machine is running Linux Mint 20.3.
The user complains that it is very slow. Mostly when the browser is open and ...
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122
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SQL DB failing to send server email - intermittent
Recently, we noticed an issue in SASS 2014 logs regarding the failure of some emails to send:
The mail could not be sent to the recipients because of the mail server failure. (Sending Mail using ...
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2
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704
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Redis Stack Server - Cannot Change Data Dir (Docker/Kubernetes)
I am trying to get redis up and running in a Kubernetes environment. I’ve done many tutorials, read the documentation, etc. etc. I need to have the .rdb file and the .aof file(s) saved in a Persistent ...
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2
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Server administration issue [closed]
How can you troubleshoot a slow server response time? My server performance is deteriorating so fastly. I've tried fixing server software and configurations. Also checked with network connectivity. It ...
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3k
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How to troubleshoot LACP flapping interface triggered by layer 3 IP Address. (Juniper)
I am currently working on solving a network issue that has led to network outages across my organization. (I have included a picture of our simple topology below). Our network consists of a Router/...
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1
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551
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Diagnosing samba fileshare issues with TP-Link router
I have a LAN with a TP-Link router (AXE5400, 3 months old), a Mac Mini (2020, osX Monterey) as file-server, and Windows 11 Laptop and a Macbook Pro laptop (c. 2020/2022). Both the Windows and Macbook ...
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738
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Ansible trouble while launching an exe through win_command
I'm currently writing a playbook about uninstalling Fusion Inventory Agent and then deploy GLPI agent 1.4 on Windows Server 2016-2022. For all the tests i detail below, i use my domain account which ...
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1
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263
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Unable to reach different network using ubuntu server as a router in gns3
My network is shown in the picture, I am trying to ping from a windows vm to an ubuntu vm in a gns3 network. But I get: "Destination host unreachable".
Network: https://i.stack.imgur.com/...
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529
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Centos 7 OpenJDK Upgrade Confusion
Wanted to pick someone else’s brain on an issue I’m having and getting nowhere with.
We have an older Linux server in our environment and I am looking to patch our openjdk to the Latest versions but ...
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Block device suddenly full; can't identify a single file as culprit and SMART shows no drive errors [duplicate]
Setup
Ubuntu 20.04
Dell PowerEdge R820
[PERC H710] 2x Virtual Drives (RAID-1 Boot, RAID-0 Work Drive)
Everything been fine for 6 months
No preceeding even, just suddenly, drive full.
Details...
This ...
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How can I see the memory content of nginx process?
Nginx 1.20.1 server working as a reverse proxy consuming a lot o memory and making the service stop requiring a system reboot. ModSecurity library is also configured on Nginx.
You can see in the next ...
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1
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3k
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No incoming traffic on Hyper-V Adapter inside VM
I have a very annoying problem with my Hyper-V setup and it's bugging me quite a bit, because I can't figure out why.
My Hyper-V Host is a Windows Server 2019 and has three network adapters.
Adapter 1 ...
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1
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77
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How to query linux kernel which storage-related operations are currently being run on the level of FS / block layer / SATA controller?
Every once in a while, our Linux LAMP server (using PHP-FPM, XFS on thin LVM on HW RAID, Centos8) becomes inaccessible and stops responding to HTTP(S) requests.
Via centralized logging we found out ...
5
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2
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2k
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Can tone ethernet cable into patch panel but it's not working
So we recently had to two major issues happen at a location.
We had a lightning strike hit the building
We updated switches after this lightning strike
Now one thing that was 'hit' was a SOHO router....
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239
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After upgrade from MongoDB 4.x to 5.0.2 shows Connection Refused trying to connect BD from Private Network
I have upgraded my MongoDB from 4.x to 5.0.2 into a Ubuntu 20.04 system. This server is an AWS EC2 Instance. After upgrade I can't connect my applications from other ec2 instances using the same ...
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277
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Something is closing connections in my CentOS VMs - how to best troubleshoot?
I have a setup with 3 VMs (1 application server on CentOS6 and 2 database servers on CentOS7). The last 1-2 weeks we have had issues with timeouts when connecting to the database servers (and between ...
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39
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Has anyone cloned an HDD for a Macintosh IIvx?
Where I work as a sysadmin, we have an old Macintosh IIvx that is the only one left in the world with an obscure program on it that will cost the company a ton of money if they can't use it. Well, the ...
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347
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router or reverse proxy - network failure
I have an edgerouter x sfp as the main router to the internet. To this router a server is connected with a reverse proxy docker running called swag eg. letsencrypt which I use to access nextcloud and ...
2
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0
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300
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WVD App attach launching windows file explorer
I'm trying to virtualize some apps and test the app attach feature with MSIX packages. I've followed all the steps, and expanded the MSIX into a VHD. I've uploaded the VHD and placed it in a hostpool /...
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590
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Remote host can be connected to via SSH but cannot connect to the Internet
I am trying to find out why a remote host with which I can connect via SSH cannot connect to the internet.
When I try to ping said server, it will answer back with 1 ping and every subsequent packets ...
2
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3
answers
3k
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Using ENV variables in Postfix and Dovecot configuration files
I'm trying to dockerize my mailing server and I'm having some troubles regarding how am I supposed to use environment variables inside Postfix and Dovecot configuration files (I'm using the latest ...
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1
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4k
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Kubernetes: kube-dns servers are not reachable (other pods are reachable)
this is an odd one.
I've setup my K8s cluster, 1 master and 1 worker. It uses calico as cni, and everything looks to be working as expected (I'm able to deploy pods, services, etc). I'm able to reach ...
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98
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Unable to see computers on site to site VPN
Windows server: 192.168.0.10
Linux server: 192.168.0.1
Network printer: 192.168.0.30
192.168.0.0/24 site to site with 192.168.1.0/24
On a computer on second subnet (192.168.1.32) I can ping the Linux ...
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340
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Could an incompatable Xeon processer cause only two of four RAM slots to be used?
Issue
With everything installed correctly, only two of my four RAM sticks are being recognized with the BIOS. I checked the QVL for the motherboard, and the Xeon E5-2628L v3 that I am using is not ...
0
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36
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All unregistered domains are being redirected to the same IP. What does this mean?
Whenever I make a request to an unregistered URL, I receive a 301 response code and I'm redirected to a specific IP. For example, in response to http GET http://dsfijewijfeif.com
I get:
HTTP/1.1 301 ...
6
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1
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11k
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What would be causing "PowerShell.exe" to hang upon opening on multiple systems and/or how can I troubleshoot it?
What would be causing "PowerShell.exe" to hang upon opening on multiple systems?
I've waited for over 60 minutes, but it never fully starts. All it does is show the blue shell window with the ...
0
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1
answer
142
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Troubleshooting "traps: proces_name[pid] general protection" memory issue on Linux
I'm trying to troubleshoot a memory issue on one of my servers. Some time ago a daemon my company is developing crashed with segmentation errors. All would be somewhat fine, but seconds later other ...
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41
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How to troubleshoot internet down every day?
Every day the server is unreachable and I need to unplug and replug it in. I cannot ping it and all web services are down. After a reboot the internet is back on again.
There are no cronjobs
fail2ban ...
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240
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how to man-in-the-middle blocking/intercepting/editing all network traffic going to a single cabled device and a server
I need to completely block and intercept and alter all packets going between two devices. possibly i need to isolate one device and block/intercept/edit ALL traffic going to and from it if i cannot ...
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2
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2k
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HP ML350 G6 will not power on
I have no lights on MB or back of power supply. I have replaced power supply and added a redundant power supply. I replaced PD board or backplane whatever you want to call it. Still same result. ...
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1
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345
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How do I troubleshoot possible drive issues on ESXi 6.7?
I have a Dell Poweredge R630 with 4 drives in a RAID. I'm not sure if it's RAID 10 or RAID 5 because I didn't order or set up the server originally and I'm just the default network admin, it's not my ...
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1
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55
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Unable to start mariadb
My ubuntu server's mariadb service was down and from running "journalctl -xe" I could see that the error must be caused by courrupted files so i append the following entry to my /etc/mysql/my.cnf file ...
3
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1
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2k
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Troubleshoot random server freezes without log entries
We are experiencing a very particular and unique problem on our C# application which is running under .NET framework 4.7.2,
in kiosk mode on Windows 10 Operating System that runs on a Lenovo ...
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1
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2k
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mysqldump cron job runs in terminal but not cron tab
I have this cron job,
/usr/bin/mysqldump -u username -p'password' MyDatabase > /backup/CronBackup/MyDatabaseBackup.sql &>/backup/CronBackup/cronBackupLog.log
I have been through this page:
...
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40
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Diagnosing increase in traffic hitting a Django web application
This question is about diagnosing the causes of elevated network traffic in an internet-facing web application.
Background: The web application in question is a Django-based forum where users upload ...
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1
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417
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iptables rejects vpn client by port
Here is my iptables commands:
sudo iptables -F
sudo iptables -A INPUT -p tcp -s 109.123.74.85 --dport 27000 -j ACCEPT
sudo iptables -A INPUT -p tcp -s 188.170.80.4 --dport 27000 -j ACCEPT
sudo ...
2
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1
answer
512
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How to troubleshoot internal DNS resolution (Windows DNS server) pointing to a local server with a static internal IP address
To better explain the set up
I have a Debian server in a private network with a static IP.
There is a windows AD server that resolves DNS for clients internally.
A domain name is already registered ...
0
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1
answer
1k
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nginx workers stack at 100% usage after X random days
I am facing a strange incident, under which my two nginx workers suddenly get stack at 100% of CPU usage after a random number of days and at the same web traffic, under which they are behaving fine ...
1
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0
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2k
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AD domain rename problems, can't add server of the same name
I have inherited an active directory domain controller, and after adding a number of servers I found that I couldn't add a server with a specific name.
I since found out the admin who built the ...
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0
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464
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Diagnosing NFSv4 Authentication Issues
I've got a couple of NFSv4 shares (with Kerberos authentication). Most of the time they work quite well, but when there's an issue they can be a pain to fix.
I put this down to them being quite ...
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0
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1k
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How to diagnose UDP connectivity issues?
I have an OpenVPN connection which was initially over UDP. After some time I started to have serious hiccups when running ssh inside that tunnel.
As seen from inside the tunnel, ssh packets were lost,...
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135
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How to interpret the debug output from Amavis->Spamassassin?
Could please someone explain how Spamassassin build the following strings:
Oct 17 14:00:30 server amavis[29497]: (29497-02) SA dbg: uridnsbl: domain amazonaws.com in skip list, host sns.eu-central-1....
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2
answers
4k
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How to determine process which makes DNS Request? [duplicate]
I have a server on AWS, GuardDuty started send me notifications:
*** "type":"Backdoor:EC2/C&CActivity.B!DNS",
*** {"domain":"libcurl.so","protocol":"UDP","blocked":false}
*** is querying a domain ...
1
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1
answer
38
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Why does LAN stops working if switch is connected to two upfeeds?is [closed]
If I connect my switch to two upstream feeds from my ISP, my internal LAN stops functioning (see illustration below).
What is it in the TCP/IP protocol that is disrupted to cause the above?
...