Author Archives: Kaven G.

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About Kaven G.

System Engineer / Network Administrator

Windows : BSOD 0x0000007E (0xFFFFFFFFC0000005, 0xFFFFF880018C9836, 0xFFFFF880009A9008, 0xFFFFF880009A8860)

I had the luck of experiencing the following blue screen on a Windows Server 2008 R2 domain controller server at boot lately :

*** STOP: 0x0000007E (0xFFFFFFFFC0000005, 0xFFFFF880018C9836, 0xFFFFF880009A9008, 0xFFFFF880009A8860)

Related facts with this server :

– Haven’t been rebooted since two years
– Windows Updates haven’t been run for two years
– Running minimalistic list of software (Avast Endpoint Protection Suite Plus)
– The server have enough free disk space
– Not any hardware or software drivers is in cause
Won’t boot in any mode (Safe mode, Last Known Good Configuration, etc.) except DSRM
– Restore from backup 30 days back does the same thing as well

Analyzing the EventViewer or the Kernel Crash Dump did not revealed anything useful beside that the system crashed because of an event that couldn’t be catched by the system! (Yes… I know!)

After trying all possible things, disabling services, boot items etc. without any positive results, I decided to remove the only piece of non-Windows software that was in the equation (even though there isn’t any trace of evidence that point to it)…

SOLUTION : Uninstall Avast Endpoint Protection Suite Plus!

Indeed, as crazy as it sound, removing Avast from the system solved this blue screen. I have filled a bug report to Avast about this and awaiting their reply. Stay tuned for update.

Linux : Apache Invalid command ‘ProxyPreserveHost’

Having the following error output trying to start, restart or do a configtest on Apache server?

Invalid command ‘ProxyPreserveHost’, perhaps misspelled or defined by a module not included in the server configuration

This is likely caused because mod_proxy module is not present or disabled. To enable it, look out for the following in the main server configuration :

Then you may attempt run a configtest and restart the Web server daemon.

Windows : How to disable ads in uTorrent client

uTorrent is a great BitTorrent client which have a free offer version.

Like any free products, ads are involved at some point. Fortunately the developers left a function for users to turn them off.

It is well hidden in the advanced features. Make sure before going forward with this procedure to not touch any other settings.

1. Go to the advanced preferences :

Options > Preferences > Advanced

2. Scroll down the list until you see option names with “offers.*” prefix and locate the following :

3. By default, it should be set to “true”, simply double-click on it to set it to “false” and click Apply.

The change should be now effective in the UI, if it does not, completely close uTorrent and start it again.

Category: PC

Linux : MySQL table is marked as crashed and should be repaired

Slow MySQL server, with very high load and consuming a lot of I/O without any particular reason? If you see the following error when looking at the MySQL log file (/var/lib/mysql.log), then now you know why!

[ERROR] /usr/libexec/mysqld: Table ‘./database_name/table_name’ is marked as crashed and should be repaired

Fortunately, this issue is probably easy fixable by using the MySQL repair tool. Assuming you already have backups (if you don’t, shame on you and take one right away!) and then, follow these steps to resolve this issue :

  • Invoke the repair tool for the database specified to have crashed table (replace <USER> by a user that have server administrative privileges) :

NOTE : If there is a lot of damaged tables, you might need to append the “–extended” option after “–repair”.

This step might take a while, I would recommend running it under a “screen” session if you are working remotely to avoid this process to be interrupted if your session get cut, this might damage the database even more.

  • If you are recovering for a major crash and many databases are shown to be affected in the log, you may use this command to check them all at once :

Linux : How to show interface IP address at boot on the console with CentOS/RHEL7?

Particularly useful when building appliances or when you ship pre-build systems to a remote location where technical knowledge of people at the remote site is limited, you can easily make the system “print” the IP acquired by DHCP or even the static assigned one to the system console login.

You will need to create two scripts in order to have this working.

1. Create the script that will get the information from the “ifconfig” output :

2. Append the following (this example assume that the interface is eth0) :

3. Change the permissions :

4. Create the second script that will invoque the first one and then send the information to the “issue” file :

5. Append the following :

6. Change the permissions :

You can now reboot your system, it should print the IP below the system information.

Windows : Time synchornization

There might be a few situations where you need more flexibility than what the clock UI can provide. In that case, you will need some help from the command line and registry.

To manually synchronize the clock with a time server using the command line :

NOTE : Replace <ntp_server> with the server IP or FQDN.

Example :

To change the time server list/source :

HKEY_LOCAL_MACHINE \ SYSTEM \ CurrentControlSet \ Services \ W32Time \ Parameters

NOTE : Edit <peerlist>, using space between the server IP or FQDN. Make sure to append “,0x1” at the end of any FQDN record.

To set the pooling interval :

HKEY_LOCAL_MACHINE \ SYSTEM \ CurrentControlSet \ Services \ W32Time \ TimeProviders \ NtpClient \ SpecialPollInterval

NOTE : Edit <period>, value should be set in seconds.

VMware : The range of ephemeral TCP ports on this system is 1025 to 65534

Upgrading from vCenter 5.5 to 6.0? Then you might have run into the following issue during the setup :

The range of ephemeral TCP ports on this system is 1025 to 65534. This range of ports is too large and the system must be reconfigured to use a smaller ephemeral port range before the install can continue.
We recommend using the default range of 49152 to 65535 (For example, by running the command “netsh.exe int ipv4 set dynamicportrange tcp 49152 16384”

And / Or :

Installation of component VCSServiceManager failed with error code ‘1603’

Obviously, VMware find out the range of ephemeral ports to be too large. You can easily scale it down to the recommended values with the step below.

Open the Command Prompt with elevated privileges (Run as Administrator…) and enter the following command :

You should get a simple “OK” output, then you can attempt to press next or start the upgrade wizard again.

Windows : Exchange POP3 “Your e-mail Server Rejected Your User Name”

If you encountered the following error trying to connect to a POP3 account on your Microsoft Exchange mail server, this might indicate the following issues :

– The POP3 protocol isn’t enabled for this account ;
– The login type you are trying to use isn’t currently supported by the server.

This usually happen when trying to use a non-SSL connection. By default, Exchange will only accept encrypted connections. If you know what you are doing and would like to allow non-encrypted connection, simply do the following :

Warning! Applying the command(s) suggested below mean that users can authenticate sending their active directory password in clear text.

1. Open the Microsoft Exchange Shell Console with elevated privileges.

2. Enter the following command to allow unencrypted login :

NOTE : The command above signify that encryption isn’t required for authentication on port 110.

Alternatively, you can set the following :

NOTE : The command above signify that encryption isn’t required for authentication on port 110 but basic authentication is only permitted on port that use TLS or SSL encryption.

The default setting is the following :

The POP3 Exchange service must be restarted after applying any of these parameters.

Windows : magicJack cannot access the internet after upgrade from Windows 7 to 10

If you own the 1st generation magicJack and you have upgraded your computer from Windows 7 to 10, you may have noticed the following error message while starting the magicJack application :

magicJack cannot access the Internet. Please click here to start magicFix.

This message show up even though your computer is connected to the Internet. It appear that the software require an upgrade for the newer version of Windows to work.

Just get the newer magicJack client version at the following address :

http://upgrades.magicjack.com/upgrade/magicJackSetup.exe

Category: PC

Linux : perl: warning: Setting locale failed

You probably noticed the following output on your console after logging to your newly installed CloudLinux server :

perl: warning: Setting locale failed.
perl: warning: Please check that your locale settings:
LANGUAGE = (unset),
LC_ALL = (unset),
LC_CTYPE = “UTF-8”,
LANG = “en_US.UTF-8”
are supported and installed on your system.
perl: warning: Falling back to the standard locale (“C”).
perl: warning: Setting locale failed.
perl: warning: Please check that your locale settings:
LANGUAGE = (unset),
LC_ALL = (unset),
LC_CTYPE = “UTF-8”,
LANG = “en_US.UTF-8”
are supported and installed on your system.
perl: warning: Falling back to the standard locale (“C”).

This does not represent any major issue, but can be quite annoying over time. To get rid of these notifications, do the following procedure.

1. Edit the following file using your favorite text editor :

2. Append the following :

NOTE : The file should be blank by default. You may adjust the above to meet your requirements if using different language or encoding.