Greatest Hits

18
votes
6answers
96k views

What firewall ports do I need to open when using FTPS?

I need to access an ftps server (vsftpd) on a vendor's site. The vendor has a firewall in front of the ftps server and I have a firewall in front of my ftps client. I understand that ports 990, 991 ...
19
votes
3answers
39k views

How do you free up a port being held open by dead process?

A colleague of mine recently ran into a problem where a process that had supposedly died was still bound to a network port, preventing other processes from binding to that port. Specifically, netstat ...
63
votes
7answers
84k views

How to forcibly close a socket in TIME_WAIT?

I run a particular program on linux which sometimes crashes. If you open it quickly after that, it listens on socket 49201 instead of 49200 as it did the first time. netstat reveals that 49200 is in ...
5
votes
8answers
94k views

How do I remove a driver completely on a Windows XP client machine?

I have a client (XP SP3) machine where newer drivers have been installed. Unfortunately while these (audio) drivers fixed mic boost, they have introduced problems such as no input working and ...
70
votes
9answers
69k views

Dump Microsoft SQL Server database to an SQL script

Is there any way to export a Microsoft SQL Server database to an sql script? I'm looking for something which behaves similarly to mysqldump, taking a database name, and producing a single script ...
49
votes
9answers
101k views

Creating a virtual machine in VirtualBox from a physical one

Is there any way to create a virtual machine that you can use in VirtualBox from a physical installation that you have? For instance, if I have Windows XP installed on a physical computer and want to ...
3
votes
3answers
39k views

How do I get SonicWALL Global VPN to work with Windows 8.1?

I have been running SonicWALL Global VPN v4.7.3.0403 on Windows 8 without trouble for more than a year. Today I upgraded to Windows 8.1 RTM and noticed that it disabled my Global VPN connection. I ...
13
votes
6answers
45k views

How do I access the list of currently logged on users through Terminal Services Manager in Windows Server 2012?

In Windows 2003 and 2008 we had Terminal Services Manager (see screenshot below). However in Windows server 2012 it's gone. Does anyone know how to access the list of currently remotely logged on ...
15
votes
3answers
39k views

MySQL lowering wait_timeout value to lower number of open connections

I run a rather busy site, and during peek hours I see over 10.000 open connections to my database server on my webserver when a run a netstat command. 99% of the connections are in the TIME_WAIT ...
17
votes
4answers
47k views

How to configure vsftpd to work with passive mode

Whenever I install vsftpd on centos, I only setup the jail environment for the users and rest is default configuration of vsftpd. I create user and try to connect with filezila ftp client but I could ...
48
99
votes
9answers
38k views

Keeping a linux process running after I logout

I'm connecting to a Linux machine through SSH, and I'm trying to run a heavy bash script that makes filesystem operations. It's expected to keep running for hours, but I cannot leave the SSH session ...
125
votes
3answers
44k views

What is the difference between double and single square brackets in bash?

I just wondered what exactly the difference between [[ $STRING != foo ]] and [ $STRING != foo ] is, apart from that the latter is posix-compliant, found in sh and the former is an extension ...
171
votes
11answers
55k views

Can I nohup/screen an already-started process?

I'm doing some test-runs of long-running data migration scripts, over SSH. Let's say I start running a script around 4 PM; now, 6 PM rolls around, and I'm cursing myself for not doing this all in ...
34
votes
4answers
114k views

Is it possible to change an “Unidentified Network” into a “Home” or “Work” network on Windows 7

I have a problem with Windows 7 RC (7100). I frequently use a crossover network cable on WinXP with static IP addresses to connect to various industrial devices (e.g. robots, pumps, valves or even ...
33
votes
4answers
45k views

How to change sshd port on Mac OS X?

I want to change which port sshd uses on a Mac server. For example, let's say from port 22 to port 32. Editing /etc/sshd_config does not seem to work. Does anyone know how to change it? I'd prefer ...
22
votes
9answers
108k views

Is there a way to clone an existing VM on an ESXi server without having to re-import it?

I have imported a VM into an ESXi server using the VMware "Converter stand alone utility". However, this process is a little tedious. Since I eventually want several copies of this VM (or, to be ...
98
votes
4answers
131k views

FreeBSD performance tuning: Sysctl parameter, loader.conf, kernel

I wanted to share knowledge of tuning FreeBSD via sysctl.conf / loader.conf / KENCONF / etc. It was initially based on Igor Sysoev's (author of nginx) presentation about FreeBSD tuning up to ...
9
votes
3answers
11k views

How do I disable SSLv3 support in Apache Tomcat?

I am trying to reconfigure my Apache Tomcat server to only use TLSv1. However, it is still falling back to SSLv3 using certain browsers. I setup the <connector> tag with the following settings: ...
4
votes
3answers
35k views

What is a Cisco BVI interface? What is it used for?

I have been Google'd and searched for the answer to these questions, but I cannot find a simple answer. So my questions are about BVI interfaces. What are they? Why do you use them? In what scenario ...
15
votes
9answers
36k views

Linux (mv or cp) specific files from a text list of files?

I have a directory of many files, something like 50,000 pdf's and other files on a server. I need to move specific ones to another directory. I can generate a list of the files that need to be moved ...
83
votes
6answers
74k views

Setting the hostname: FQDN or short name?

I've noticed that the "preferred" method of setting the system hostname is fundamentally different between Red Hat/CentOS and Debian/Ubuntu systems. CentOS documentation and the RHEL deployment guide ...
79
votes
4answers
45k views

Moving an already-running process to Screen

My office job routinely sees me connected to a Linux box via VNC. Sometimes I start a remote job on the console, and realize later that it runs much longer than expected. (Should have started that ...
58
votes
2answers
49k views

how to disable SSH login with password for some users?

On Linux (Debian Squeeze) I would like to disable SSH login using password to some users (selected group or all users except root). But I do not want to disable login using certificate for them. ...
5
votes
6answers
65k views

How do I completely remove MySQL from a linux installation?

I was surprised to find that one of my privileged users installed MySQL on a linux box. The server (mysqld) is running and doing nothing. My skills are all in Oracle, so I am unfamiliar with how to ...
4
votes
3answers
16k views

Best way to gracefully restart CentOS?

I always used the command: shutdown -r now However, sometimes that causes MySQL issues. What's the most graceful way to restart CentOS? I've seen: reboot and halt How can I gently reboot ...
68
votes
11answers
10k views

How bad is it really to install Linux on one big partition?

We will be running CentOS 7 on our new server. We have 6 x 300GB drives in raid6 internal to the server. (Storage is largely external in the form of a 40TB raid box.) The internal volume comes to ...
31
15
votes
4answers
42k views

How do I sleep for a millisecond in bash or ksh

sleep is a very popular command and we can start sleep from 1 second: # wait one second please sleep 1 but what the alternative if I need to wait only 0.1 second or between 0.1 to 1 second ? ...
15
votes
11answers
104k views

Best way to find the computer a user last logged on from?

I am hoping that somewhere in Active Directory the "last logged on from [computer]" is written/stored, or there is a log I can parse out? The purpose of wanting to know the last PC logged on from is ...
52
votes
8answers
106k views

What limits the maximum number of connections on a Linux server?

What kernel parameter or other settings control the maximum number of TCP sockets that can be open on a Linux server? What are the tradeoffs of allowing more connections? I noticed while load testing ...
14
votes
11answers
70k views

How do I find out which devices are on a network?

How do I scan a network to find out which devices are on it? (I'd be happy with a list of MAC addresses and IPs.) For example, lets say I'm at work and want to be sure that there are no unknown ...
62
votes
2answers
87k views

How to Configure Windows Machine to Allow File Sharing with DNS Alias

What process is necessary to configure a Windows environement to allow me to use DNS CNAME to reference servers? I want to do this so that I can name my servers something like SRV001, but still have ...
34
votes
4answers
75k views

How do I grant start/stop/restart permissions on a service to an arbitrary user or group on a non-domain-member server?

We have a suite of Windows Services running on our servers which perform a bunch of automated tasks independently of one another, with the exception of one service which looks after the other ...
14
votes
4answers
33k views

Unknown/unsupported storage engine: InnoDB | MySQL Ubuntu

I recently upgraded from the previous LTS Ubuntu to Precise and now mysql refuses to start. It complains of the following when I attempt to start it: ╰$ sudo service mysql restart stop: Unknown ...
11
votes
3answers
21k views

How to Restart explorer.exe Remotely?

I'm having big troubles with a remote server that for some reason explorer.exe crashed and, although I didn't lose remote desktop connectivity, I can't do anything. Is there a way of restarting ...
22
votes
6answers
82k views

Finding why a user is locked out in Active Directory

A user's account keeps getting locked out in Active Directory. It's probably caused by an app that's using Windows authentication to connect to SQL Server. Is there a way to find out which app is ...
13
votes
12answers
44k views

Is it better to use the 192.168.x.x or 10.x.x.x address range for a small business network?

For best performance and ease of management, is it better to use 192.168.x.x or 10.x.x.x range of addresses for a small (<50 PCs) business network? This would correspond to a subnet of 255.255.0.0 ...
31
votes
7answers
76k views

Why do I get sqlite error, “unable to open database file”?

Using my Django app, I'm able to read from the database just fine. When the application didn't have permission to access the file, it gave me this error: attempt to write a readonly database ...
5
votes
11answers
70k views

Windows command prompt: how to get the count of all files in current directory?

What command would you use in cmd.exe to find the number of files in the current directory? Is there a powershell option here? Update: I was hoping to avoid dir, as I know there are 10,000+ files in ...
20
votes
5answers
31k views

hosts file ignored, how to troubleshoot?

The hosts file on Windows computers is used to bind certain name strings to specific IP addresses to override other name resolution methods. Often, one decides to change the hosts file, and discovers ...
16
votes
2answers
31k views

How to make wireshark filter POST-requests only?

How to make wireshark filter POST-requests only?
13
votes
5answers
21k views

Apache2 config variable is not defined

I installed apache2 on ubuntu 13.10. If I try to restart it using sudo /etc/init.d/apache2 restart I get this message: AH00558: apache2: Could not reliably determine the server's fully ...
0
votes
3answers
20k views

phpmyadmin “Forbidden: You don't have permission to access /phpmyadmin on this server.”

I need to modify the file /etc/httpd/conf.d/phpMyAdmin.conf in order to allow remote users (not only localhost) to login # phpMyAdmin - Web based MySQL browser written in php # # Allows only ...
9
votes
1answer
61k views

What is a SQL Server instance?

When I install SQL Server 2008 Express in prompts me to create an instance and aborts if I don't. Then I see that information in an entry in Sql Server Configuration Manager on SQL Server Services. ...
8
votes
8answers
56k views

SSL Error - unable to read server certificate from file

I've been setting up SSL for my domain today, and have struck another issue - I was hoping someone could shed some light on.. I keep receiving the following error messages: [error] Init: Unable to ...
32
votes
10answers
47k views

How do I get apt-get to ignore some dependencies?

How do I make apt-get ignore some dependencies? For example, I wanted to install mailx so I can use it to send email from cron scripts/report-generating tools. However, installing mailx also installs ...
7
votes
10answers
46k views

Exchange 2010 and Outlook 2010 requesting password every time it starts

I have one Exchange 2010 server which is fully updated, the clients are running Outlook 2010 but some users are getting a prompt for credentials every time they open Outlook. I have checked for ...
17
votes
5answers
58k views

What is the value of JAVA_HOME for CentOS?

I have install java through yum on CentOS, however another java programme needs to know what the JAVA_HOME environmental variable is. I know all about setting environmental variables, but what do I ...
14
votes
8answers
66k views

How to make a bootable USB drive out of a bootable DVD or CD

Is there a "universal" way of how you can make a bootable USB drive out of a bootable dvd or cd? What makes a USB drive bootable? What makes a dvd and cd bootable? For example there is a program ...
6
votes
7answers
59k views

How do I permanently change the hostname on Solaris 10?

I want to permanently change the hostname on a Solaris box. How do I do that?
65
15
votes
4answers
50k views

VirtualBox: How to set up networking so both host and guest can access internet and talk to each other

I was wondering if someone could give me a simple guide on how to set up virtual networking in VirtualBox (4.0.2) so that the following scenarios work: Both Host and Guest can access Internet Host ...