Questions tagged [troubleshooting]
Troubleshooting is a form of problem solving, often applied to repair failed products or processes.
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Internal e-mails
We need to send mails from our domain (assume this is example.com) to our self. Now, the 'incoming' mails are handled by another server (from Google). We can send mails through sendmail to external e-...
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Putty + Bash + Screen, up arrow for history not working (Ubuntu 11.10)
I have a fresh install of Ubuntu Server 11.10 that I am logging into SSH via PuTTy. When I am inside screen, I cannot use the up arrow to recall bash history (though this works outside of screen). I ...
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How to troubleshoot many failed pageloads?
I've had a few cases in which the homepage of one of my sites wouldn't load in the browser. The site is running on django/fastcgi/nginx.
It was difficult to reproduce so, in an attempt to understand ...
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Troubleshooting potential compromised server from Brute Force SSH Attack [duplicate]
Possible Duplicate:
My server's been hacked EMERGENCY
So I noticed some files/folders on my webserver and investigating leads the fact that a brute force attack via SSH was done on my server (...
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nginx redirecting for no reason?
This was really annoying and now i see when it happens. If <ip>/NAME exist in /var/www (/var/www/NAME) nginx will give me a redirect to www._.com/NAME/ (note the slash and lack of url) which is ...
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Trying to bridge NIC. What does this error mean?
I would like to bridge between br0 and tap0 for my OpenVPN server, but I get the error at the bottom of this post.
Background
The server have one physical eth0 with IP xxx.xxx.68.58.
The bridge ...
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Troubleshooting Nagios alerts; aka. Why aren't my alerts firing?
I'm attempting to add email alerts to an existing Nagios install. I've been using the web interface to keep an eye on some non-critical systems for a few months and it's been running well; warnings ...
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3
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Ubuntu 10.04 install is missing /etc/rc0.d, is there a quickfix?
I have no idea how this happened, but /etc/rc.*/ is simply missing.
As a result, aptitude and apt-get don't work right anymore.
Is there a quick-fix for this? I really don't want to reinstall the OS ...
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Performing root-cause analysis
I want to learn more about how to perform root-cause analysis. More times than not, our department tells the user to try rebooting (thier Windows XP system), which actually "fixes" a good number of ...
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Proxy-Connection Header associated with failed connections
I work with microprocessor devices that have/run a micro webserver.
I have two of these devices set up so that they can be accessible to/by the Internet - I'll call the devices "A" and "B".
...
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End-user SSL certificate management workflow [closed]
We have an internal website, served from behind HTTPS with client certificates.
Website users are non-technical persons, working remotely. They use Windows (XP, Vista, 7) and OS X (10.5, 10.6, 10.7). ...
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Ubuntu troubleshooting
I have a computer which keeps becoming unreachable, and a restart fixes the problem. It's under somewhat heavy load (high cpu, and high ram usage), but appears for the most part stable.
What's a good ...
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Server is rebooting unexpectedly, strange kernel messages in log file
I have a server running Ubuntu 10.04 that is rebooting several times a day it seems, and I can't figure out why. It doesn't appear to be a graceful reboot either, because some of the services complain ...
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SSH closes connection when key is accepted
In server's auth.log:
Failed publickey for agladysh from MYIP port 61313 ssh2
In ssh -vvv:
debug1: Offering public key: /Users/agladysh/.ssh/id_rsa
debug3: send_pubkey_test
debug2: we sent a ...
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LAN - troubleshooting
I have 2 clients on my LAN that I'm trying to get to "see" each other. The first as follows
Computer1
IP 172.21.62.230
Subnet 255.255.255.224
Default gateway 172.21.62.225
Preferred DNS server 172....
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Troubleshooting firewall and routing on Linux
Are there any tools or API hooks for troubleshooting iptables or routing on Linux? (besides the obvious -j LOG)
In other words: what to do when tables with 200 or 300 firewalling rules after adding a ...
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VMWare Workstation connection problems
Our old setup (which worked):
On workstation W-1 (WinXP - 64bit) we had two virtual machines (VMWare 6.5) V-1 and V-2 (both with WinXP-32).
All of them had a different IP static address, V-1 and V-...
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Troubleshooting linux server reboots?
I have a Linux server I've just set up, debian squeeze, 2.6.32-5-amd64, and over the past week it's rebooted three times, twice in one day. There was no power outage that I am aware of (and it's ...
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my ssh sessions are randomly killed on Debian
I have a Debian 6.0.1 vanilla install, and I use PUTTY to ssh into it. I will usually have 3 or 4 PUTTY login shells running at the same time.
What I'll find is that if I leave my computer for a ...
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High ping everywhere except one PC
I have a network with a really high ping (usually more than 500ms) except for one laptop. And in that laptop the ping is usually 5ms.
I've tried:
- using same model laptop
- compare lan driver ...
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Troubleshoot DBMail in SQL Server 2005
On a SQL Server 2005 machine, I have DBMail setup and correctly configured. I am able to use "Notify Operator" and EXEC msdb.dbo.sp_send_dbmail to queue emails.
But the problem is the queued mails ...
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2
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troubleshooting a printer problem
I have a large Kyocera Printer/Scanner/Copier machine in a office with three PCs (all plugged into a lan via router. The three PCs all have individual printers (inkJets) hooked directly via printer ...
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ADFS 2.0 Errors Event ID 184 & 364
I have ADFS servers set up and each component such as in URN, relay, claims etc. in place, but am getting this error massage
"There was a problem accessing the site. Try to browse to the site ...
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Cannot mount /dev/sdc1 on Debian 5.0, special device /dev/sdc1 doesn't exist
I'm trying to fix an odd problem I'm having that I've never seen or heard of before. I have a disk, /dev/sdc and I'm trying to mount it, but cannot.
sudo mount /dev/sdc1 /mnt
mount: you must ...
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Port forwarding not working, tcpdump shows "reset connection"
I have an home web server that I use to serve a few pages for personal purposes. The server runs Ubuntu and is behind an ADSL connection, and it's working nicely.
Recently I subscribed to a Hiperlan ...
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How can you identify why a Windows service (TeamCity build agent) is hanging when running a command?
I've got a problem with a Windows service I just simply can't get to the bottom of. What I'm trying to do is execute the HP WebInspect 9.0 application from a TeamCity build agent which runs as a ...
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mac OS X version 10.6.5 network connection troubleshooting/solution?
Im connected to a small office network where where everything works fine. however once in a while or on a random occasion usually after the computer has been left on or on sleep all night there are ...
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DHeapmon not reporting expected number of total desktops in IIS6
Hope someone can help me make sense of this. I'm trying to debug some COM+ errors we see in our production environment and a few of them report that the desktop heap is exhausted, so I installed ...
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DNS oddities with different nameservers
My ISP's DNS servers are sometimes sketchy, so I use 4.2.2.1 and 8.8.8.8 respectively. The Layer 3 DNS server and Google's DNS server.
Sometimes there will be a long delay in resolving, and if I ...
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COM+/Desktop Heap errors in IIS affecting sites at random?
We have a Win2K3 server that is hosting 30+ sites. Each site is configured to have its own unique application pool -- so that we can manually recycle specific sites if needed and not kill sessions ...
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How do I troubleshoot network connectivity problems in windows?
I'd really like to understand how to debug my network connectivity issues, but everything I find on the internet is either for basic users on "How to add a wireless network" or it's people talking ...
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What causes the issue (possibly packet loss) in this scenario
I'm trying to diagnose a network related problem - please understand these points before suggesting an answer (apologies if more information is required, I will add anything people ask).
We have a ...
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Random Ubuntu server network disconnects
After installing Ubuntu Server 10.04.1 on a new x86_64 kvm instance (Debian
6.0 hosted) I'm getting -apparently- ramdon disconnects from the server.
Read from remote host myserver:
Connection reset ...
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Open ports broken from internal network [duplicate]
Quick summary: Forwarded port works from the outside world, but from the internal network using the external IP the connection is refused.
This is a simplified situation to make the explanation ...
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Page allocation failure - Am I running out of memory?
Lately, I've noticed entries like this one in the kern.log of one of my servers:
Feb 16 00:24:05 aramis kernel: swapper: page allocation failure. order:0, mode:0x20
I'd like to know:
What exactly ...
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Troubleshooting PXE Boot in CentOS
I am working on troubleshooting a PXE server that we have setup for use. It is based upon Cent OS 5.5. We installed the following components on top of a relatively vanilla install of Cent OS:
tftp-...
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3
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Resources on Java for Sys Admins? [closed]
I've been fortunate enough to make it four years as an SA without having to administer systems making use of Java. My luck has run up and I am starting a new job and they make extensive use of Java. ...
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How to analyze which virtual host account is most greedy?
Hi there and sorry if this is too noobish.
I've tried to find the answer myself as I usually do but I failed.
What is the best practice when I need to analyze which virtual hosts are consuming the ...
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Fixing BIND9 rndc error "connection to remote host closed"
I just made some changes to a DNS zone in Webmin and clicked the "Apply Changes" button. I received the error message:
rndc: connection to remote host closed This may indicate that the remote ...
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585
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VMware server 2.0 SYN/ACK repeating issues
VMWare Server 2.0.0 Build 122956
I am having some issues with connecting into a guest VM (Ubuntu linux 4.4.3-4 lucid) running under VMware 2.0 on a windows server host.
All connections to and from ...
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Need help trying to diagnose Symmetrix SAN performance issues
I am helping to benchmark hardware for a new SQL Server instance, and the volume presented to the OS for the data files is carved from a set of spindles on a Symmetrix SAN. The server has yet to have ...
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My Ubuntu 10.04 server kills all WAN bandwidth when it's attached to my LAN. Where do you begin troubleshooting?
First I should say that my Linux knowledge is minimal; just enough to set up some servers (Apache, Tomcat, Couch, etc). I built a MiniITX server to host some simple sites, act as an SSH tunnel while I'...
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Troubleshooting why my SSH sessions hang for a couple of seconds
I'm logged in to my development box via SSH (using PuTTY on my laptop) and periodically, the session would just hang for a couple of seconds then becomes responsive again. I have not been able to ...
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What steps should I take to determine the root cause of linux server failure?
I am sorry if this question has been addressed before, I am assuming it has, but after a half hour of searching I couldn't find anything.
Anyway, to the question:
I am a windows guy and a self-...
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VPN troubleshooting
I have a user that is having trouble VPN to the office. What are you top troubleshooting things to try to find out where the problem is.
The error the user is getting is Error 806 - a connection ...
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Apache Permission issue
How do I resolve an issue of permissions in apache. The initial task that I am trying to get working is to upload a mura plugin the the temp directory of ColdFusion9. However, I have since discovered ...
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blat.exe getting deleted from my servers
we're using blat.exe as part of many of our setups on Windows Server 2003 SP2 without any problem to send mails via command line. It's simply great.
Now, some software we are using provides blat.exe ...
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RSA Authentication Manager - Unable to resolve principal by login ID and/or alias
I'm attempting to setup a RSA authentication manager with a Microsoft Active Directory as the identity source. When I try to login from the Windows login client the login attempt failed and I recieve ...
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How can I diagnose an Ubuntu system freeze after reboot
One of our servers froze yesterday, apparently refusing to serve any HTTP requests. The tech guy on site could not connect remotely to the machine, so he rebooted the (virtual) machine from the VMware ...
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Unexplained Opsview configuration error
Somehow I've broken by Opsview configuration, and it gives me a completely unhelpful error: critical 2010-10-12 12:09:57 Cannot reload:. It looks like there should be more info, but there's not.
I ...