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File extension in Windows Explorer, How to view!

How to make File extensions in Windows Explorer visible

For Windows 10 and 11, the file extensions are hidden by default. In Windows 11 open View in the toolbar and scroll down to Show and choose File name extensions.

The file extension is often used to identify the format of a file. For example: name.txt indicates a text file. Modern Windows versions do not know the limitation of file names, like the 8.3 convention known by MS-DOS (8 characters file name, 3 characters extension). In Windows 10, the default setting is that all extensions known to the system are hidden in Explorer. This fact is exploited by various malware programs. To make the file extension visible, go to the Explorer options in the Control Panel, or call up File Explorer Options directly.

File extensions for known file types

In Windows 10 explorer ribbon click the checkbox File name extensions or click the options button in the view tab to open File Explorer Options.

Windows Explorer File name extensions

Alternatively, there is the option of calling the MMC console directly.

Windows Run control folders

Press the Windows + R key and hit control folders and click OK

In the File Explorer Options, the setting for file extensions can be hidden or displayed in the View Tab.

File extension in Windows Explorer, Hide extensions for known file types

Uncheck Hide extensions for known file types and click OK. Any files are now displayed with extensions.

Windows 11 Show File name extensions

In Windows 11 it has become easier, in the explorer open View in the toolbar and scroll down to Show and choose File name extensions.

Windows 11 File explorer Show File name extensions

The filename extensions with type for all files in Windows 11 File Explorer will now displayed.

quote  With regard to system security, the visibility of the file extensions is also recommended, as malware and Trojans are less able to hide because the extension identifies the type and which program the file is associated with.

quote  A related post here that might also interest you!

Common filename extensions

Many operating systems do not limit filenames to one extension shorter than 4 characters. It as was common with some operating systems that supported the File Allocation Table (FAT) file system. Operating systems that do not impose this limit include Unix-like systems, and Microsoft Windows NT, 95-98, and ME. Which have no three character limit on extensions for 32-bit or 64-bit applications on file systems other than pre-Windows 95 and Windows NT 3.5 versions of the FAT file system. Some filenames are given extensions longer than three characters. While MS-DOS and NT always treat the suffix after the last period in a file’s name as its extension, in UNIX-like systems. The final period does not necessarily mean that the text after the last period is the file’s extension.

This is a list of common Windows file name extensions, organized by type.

SSH Login with PuTTY Key Authentication

PuTTY SSH login with using puttygen key pairs

SSH authentication via asymmetric keys is more secure than using passwords, further public key authentication also enables automated login, for example to log in from scripts without a password request. The PuTTY Key Generator puttygen.exe is used to generate RSA (standard) or DSA and ECDSA key pairs.

The tool can be found at putty.org via Download PuTTY, if you have install PuTTY using the putty-installer.msi, then puttygen can already be found in the Windows Start menu under PuTTY. To create an RSA key pair, just click on the Generate button. If you want to generate DSA or ECDSA keys, the desired algorithm can be choose at the parameter box with radio button.

Generate PuTTY Key Pair in puttygen

The necessary random mechanism is provided by moving the mouse freely in the free area of the dialog box during key generation. Then you can enter optionally Key passphrase.

PuTTY Key generate

To save the private key be click on the button Save private key, in the dialog “are you sure you want to save this key without a passphrase to protect it!“, you can decide to save with or without passphrase. The save of the public key is not absolutely necessary, because it can be calculated at any time from the private key.

The private key should be kept in a safe place, especially if the private key is not protected by a passphrase. Once a private key has been lost, unauthorized persons cannot do anything, if is protected by a passphrase. On the other hand, in the case of automated processing by scripts, a passphrase is not desired.

The file name and the path when saving are free of choice in the chooser, but the extension .ppk has spread for PuTTY keys, because there is a reference to the format that differs from Linux. PuTTY does not accept OpenSSH keys, but in the Conversions menu it is possible to import existing OpenSSH keys and also to export PuTTY keys.

Save Public Key to server

The public key should be published on the server, completely mark it with the mouse in the Key field and copy it to the clipboard with Ctrl+C.

PuTTY Key Generator Public key pasting into authorized_keys

Just log in with PuTTY again with username and password on the Linux server, open the file ~/.ssh/authorized_keys with an editor of choice and insert the public key from the clipboard.

  Do not changed anything on the key, just copy & paste. The file authorized_keys can contain several keys one after the other, without spaces or lines in between.

Use PuTTY with Private Key

To use public key authentication next time you log in, go to the PuTTY start page Basic options for your PuTTY session in the Session area enter the IP address or the Host Name, for Saved Sessions you enter a desired name and click on Save, but first choose the file name of the private key in the Category under Connection click + on SSH they opens the Auth area with Private key file for authentication field. The easiest way to do this is to click on Browse and select the appropriate file in the file chooser.

PuTTY SSH Key Authentication

The credentials for each individual connection can be stored as a session. If a connection is now established to the Linux server, it requires the identity, so that the specified user name must have a public key specified in the file authorized_keys which matches the private key.

Now it asks for the passphrase (if entered) to activate the private key stored in the local .ppk file. If both keys are matched access will granted.

SSH configuration on Linux server

On the Linux server, the SSH server configuration for SSH authentication via asymmetric keys must be activated, with most Linux distributions public key authentication is activated by default /etc/ssh/sshd_config.

#PubkeyAuthentication yes
#RSAAuthentication yes
AuthorizedKeysFile      .ssh/authorized_keys

  OpenSSH: A leading hash (#) character means that it is the default value, if you would change the value, removed # and modify the parameter.

The users manage their public keys under $home in the key file ~/.ssh/authorized_keys, after creating it with adduser the .ssh directory is usually not exist, in this case it is made as root for the user john as follows.

$ cd /home/john
$ mkdir .ssh
$ chown john:john .ssh
$ chmod 700 .ssh
$ touch .ssh/authorized_keys
$ chmod 600 .ssh/authorized_keys

  The .ssh directory is not visible to other users.