A Technical I.T./DevOps Blog
Problem scenario
You want to run the puttygen command on a Linux server. (You tried yum and dnf commands to install putty, but they failed.) What do you do?
Solution
Prerequisites
i. These directions assume you have installed the C compiler. If you need assistance, see How Do You Install a C Compiler on Linux?
ii. These directions also assume you have the GTK library installed.
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Continue reading “How Do You Install the Putty Utility on a Linux Server?”
Problem scenario
You are modifying /etc/security/pwquality.conf. Is it a recommended practice to have no or few repeating characters with different classes of characters including lowercase, uppercase, numbers and special characters?
Solution
It can be counter productive to have very strong password requirements according to the NIST (https://pages.nist.gov/800-63-FAQ/).
If you are using Linux or Unix, NIST does suggest you use a crack library dictionary (per A-B10 from https://pages.nist.gov/800-63-FAQ/).
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Continue reading “Is It a Best/Recommended Practice to Enforce Complex Passwords?”
Problem scenario
You think that the users should not click the “make visible” option when entering a password. As an I.T. professional, you are not sure if this should be used or not. You read and think that it should not be used. Is it recommended that you have a practice of not letting the users make the password visible?
Solution
It is not clear.
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Problem scenario
You want to implement a secure protocol for authentication. You want there to be a password and a second factor of authentication. Can an email (being in possession of an inbox) be a factor in MFA?
Answer
Maybe.
No, according to NIST: https://pages.nist.gov/800-63-FAQ/
But many companies do use email as a factor in multi-factor authentication.
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One of the following apply to your situation:
Problem scenario #1
You are running a quotacheck command. You get this error:
quotacheck: Cannot guess format from filename on /dev/mapper/ubuntu–vg-ubuntu–lv. Please specify format on commandline.
quotacheck: Cannot find filesystem to check or filesystem not mounted with quota option.
What should you do?
or
Problem scenario #2
You try to run an edquota command,
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Problem scenario
You run a quota -au or quota -ag command to see the latest/up-to-date statistics. You see the number of blocks or inodes is discrepant with what is currently on your system for the user or group. You tried rebooting, but that did not help. How do you get the use blocks and used inodes to be updated with a quota command?
Possible Solution #1
Run a command like this:
sudo quotacheck -vug
If you think something is still misleading/inaccurate,
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Continue reading “How Do You Get quota Commands to Return Current Data?”
Problem scenario
You are printing out some dates with a Python program. You are using the datetime module and the strptime method. The year is always defaulting to 1900 because the log entries have no year designated in them. How do you seed the dates with a specific year of your choice?
Solution
Here is an example of how to seed the dates with the year 2021 (but it assumes you have a file name auth.log with dates without years in it):
import datetime
from datetime import datetime, …
Continue reading “How Do You Set a Date-Time Value with a Default Year in Python?”
Problem scenario
You know hackers and malicious social engineers love passwords. You are considering enforcing password rotations temporally (as a systems administrator, security consultant, or I.T. manager). You want planned periodic password changes to happen in a mandatory way. In theory if a password was once lost, changing it mitigates the damage. This is intuitive and consistent with a variety of sources. Many OSes and LDAPs facilitate built-in password expirations based on time intervals.
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Continue reading “Is It a Best/Recommended Practice to Rotate Passwords?”
Problem scenario
You have a stackable GE washer. The cylindrical basin of the washing machine allows for clothes items to disappear into the cubic chasis/frame of the washing machine. You are missing a washcloth, a sock or a glove. (You may or may not have seen it fall over the cylindrical tub basin into the square body of the washer when taking out the clean clothes. Sometimes an item just spins into the crevice between the agitator basin and the external body of the washer.) You want to get this small clothes item from your washing machine.
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Continue reading “How Do You Get a Lost Clothes Item in a GE Washer?”
Question
Are container layers immutable or can one be written to?
Answers
Maybe they can be written to. It depends how you define a layer.
Here are quotes and sources that say you cannot write to a layer:
The layers of a container image are all immutable. Immutable means that once generated, the layer cannot ever be changed.
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