You probably saw following message “Sorry, but Nagios is currently not checking for external commands, so your command will not be committed” when you tried to reschedule a service check in nagios web interface. The reason behind this is that nagios by default does not check for external commands. To resolve that problem we need to reconfigure nagios.
When you connect to Cisco device using telnet or ssh, you often see information message, which is called login banner. You can use login banner to display the information message that access is allowed only for authorized personnel. However banner login can used by malicious users to easier identify your device, so I will show you how to disable it. Just bare in mind that configuration of login banner should be done according to your company’s security policy, some companies may required predefined message to be displayed.
Access Control Lists (ACLs) provide a much more flexible way of specifying permissions on a file or other object than the standard Unix user/group/owner system. Windows users get used to having the ability to create complicated access control list to files and folders because ACL support was built in NTFS file system from early beginning. Many Linux users thinks that they are limited to standard Unix permission schema, however it is not true. In Linux we can also use ACL, we just need to mount the file system with proper options. ACL are available for ext2, ext3, ext4, reiserfs and several other file systems. Since 2.6 kernel acl extension is compiled by default on Debian, Ubuntu and several other major distributions.
shutdown is a small tool that enables to shutdown Windows OS from command line. shutdown tool can be used to either shutdown or restart local or remote computer. To shutdown or restart remote computer you have to use /m switch for example: shutdown /m \\RemoteComputerName /s /t 0 however sometimes you can receive following error:
RemoteComputerName: The entered computer name is not valid or remote shutdown is not supported on the target computer. Check the name and then try again or contact your system administrator.(53)
The solutions is quite simple and it is related to firewall setup between computer from which shutdown tool was invoked and target computer.
When you try to run ASP.NET website in written in MVC3 framework, by default Modernizr java script library is being appended to your razor files. Modernizr library is open source that helps building HTML 5 websites, by providing fallback for older browsers. When loaded Modernizr tries to detect your browser features and if your browser does not support some features provide a graceful fallback. In most cases it works like a charm, however I faced a problem when trying to develop new website in Visual Studio 2010 on Windows 7N. Each time I tried to run the solution the following error popped up in Java Script debugger in Visual Studio.
When you work on development with Entity Framework you can see below error.
CS0012: The type 'System.Data.Objects.DataClasses.EntityObject' is defined in an assembly that is not referenced.
The first step is to add a References to System.Data.Entity under References in Visual Studio. Right click References folder and choose Add Reference, from the list you have to choose following assembly:
System.Data.Entity, Version=22.214.171.124, Culture=neutral, PublicKeyToken=b77a5c561934e089
However sometimes it is not enough and you have to modify your Web.config file.
Are you tired of managing your Windows Active Directory using Active Directory Users and Computers, have a go and try using built-in tools like dsmod, dsquery, dsget to do your routing tasks. I am really surprised that many Windows administrators have not heard them or using them during they daily tasks and prefer to do everything by hand from dsa.msc. Below post will show how easy and fast is to enable and disable user using dsmod.
Adding user to server role is very simple task if Sql Server is working correctly, but what should we do if it was misconfigured by us or someone else. In such way that our login now longer works, sa login is disabled and we do not have any other login which would allow connect to Sql Server. This is situation is bad but it is not dramatic, we can use simple procedure outlined below to resolve the problem. The presented approach is based on the fact that our user (Windows user no matter if we are using AD or not) have administrator rights on Windows. Hence it implies that I will have full rights to Sql Server, when Sql Server will work in single user mode.
Removing Read Only attribute is quite common task everyday work. We can always use Windows Explorer to remove Read Only attribute. However sometimes removing Read Only attribute should be just a small part of our script and Windows Explorer method is not an option. Alternatively to PowerShell we could use our good old friend attrib command, but I am PS fan and I would like to share with you how to do it in PowerShell.
Email address validation is one of the most common validations used used by sysadmins and developers. There are many approaches we can use, some of us prefer to write their own function, some will choose using 3rd party library. I will show the method which is “built-in” the PowerShell, Email Validation using System.Net.Mail.MailAddress class.