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Archive for December, 2011

How to fix “missing required fields” warnings in Rich Snippets Testing Tool

Posted by Anton Khitrenovich on December 24, 2011

Several days ago I checked what Google’s Rich Snippets Testing Tool thinks about this WordPress-based blog. The results were not bad in general, but also not good enough for my understanding. While Google was able to detect that I am the owner of the blog and presented a link to my Google+ Profile, and the main page of the blog was correctly detected as a list of blog entries, each one with the permalink, a list of tags and a list of categories – the most important things were missing: the title, the date and the author of the post. The following errors were displayed for each blog entry:

Warning: Missing required field “entry-title”.
Warning: Missing required field “updated”.
Warning: Missing required hCard “author”.

Obviously, I started to check what can be done about that. Read the rest of this entry »

Posted in HOWTO, Miscellaneous | Tagged: , | 54 Comments »

How to install Admin Pack for Windows 2003 on Virtual Machine

Posted by Anton Khitrenovich on December 14, 2011

The internet is full of complains that Admin Pack for Windows 2003 cannot be installed due to protected Windows files. I guess that this can happen for various reasons, but I have found a solution for at least one of the cases – when the server where the installation of Windows 2003 Admin Pack fails is virtualized.

So, we have two servers – Windows 2003 Server with Active Directory installed as Domain Controller (server #1) and VM with Windows 2003 Server that is a member of this domain (server #2). The need – administer DNS and DHCP settings of AD remotely, but corresponding MMC snap-ins are not available by default on non-DC machines. The correct way is to install ADMINPACK.MSI, available from Windows 2003 installation CD-ROM or from Microsoft Download Center. (Of course, you can always open an RDP session to a DC – but this does not address the real need.)

However, the installation suddenly shows a message “The Windows Installer service cannot update one or more protected windows files” and rolls back everything that was already installed. The Event Viewer reveals error numbers (“Error 1933. … SPF Error: 1223.”) and the list of protected files – but this does not really help. So, what can we do about that?

In fact, the solution is really simple. Running the same installation via the console RDP session (or in the vSphere console) reveals the real cause for the failure – the Admin Pack install needs Windows 2003 installation CD-ROM, but for some reason does not tell that on non-console sessions. After the requested CD is provided (for VMs, this can be done by mounting the CD image in vSphere or via DaemonTools), the installation was able to complete successfully. Read the rest of this entry »

Posted in HOWTO, Troubleshooting | Tagged: , , , | Leave a Comment »

How to configure iptables to allow incoming web traffic

Posted by Anton Khitrenovich on December 4, 2011

One day you need to enable a web server on your Linux box. The steps look simple: turn on httpd, set some content under web root directory – and you are done. Quick test via “telnet localhost 80” assures you that the server is up, and you are going to test it in a browser from other machine… Nothing! In the best case (of Google Chrome) you will get “Error 109 (net::ERR_ADDRESS_UNREACHABLE)”… Actually, this is a good hint for you that the HTTP port on your fresh web server is blocked by internal firewall (in case of Linux it is typically “iptables”). BTW, another test that can give you additional indication is to try to connect to external IP address using telnet from inside the server.

The solution is very simple – add HTTP port to the list of allowed port in iptables configuration. There are many tutorials that explain how to do it via the command line:

iptables -p tcp --dport 80 -j ACCEPT

…but those changes will not survive the VM reboot. The right way is to edit iptables configuration file “/etc/sysconfig/iptables” directly (see example for RedHat-based systems below).

Read the rest of this entry »

Posted in HOWTO | Tagged: | 2 Comments »