Category: How To

Virtualization Tutorials, Operating System Tutorials, Software Tutorials And Other IT Tutorials

Daylight Saving 1

Iran Daylight Saving on March 2023

The government of Iran has announced that daylight savings will not be observed from March 2023. But apparently, this issue has not been properly coordinated with international institutions. So this was cause of many issues on public services in Iran. We did some updates and configuration changes before 22nd March 2022 and I want to share the story with you.

NFS (Network File System)) 1

NFS Client Configuration For My Dummy Colleagues

NFS (Network File System) is the most popular file sharing for Linux systems to access files from remote client. NFS can be very troublesome because of misconfiguration. The most challenges with NFS is network interruption and connection problem between client and server.

VMware Horizon Connection (Session) Duration 2

Connection (Session) Duration Report: Best Solution for VMware Horizon View 7.x or Newer

VMware Horizon View provides solutions for remote working and access to business from anywhere. Users be able to use virtual desktop or applications via secure and fast display protocols such as PCoIP or VMware Blast. VMware did support monitoring VMware Horizon View via vRealize Operations (vROps) for Horizon but recent versions are not supported. You have to use third-party software or services such as ControlUp or develop your solutions.

Linux Distribution 1

HBA Port and Linux: What’s The Best Solutions to Disable?

Sometimes you need to do troubleshooting about storage connectivity but you don’t have access to datacenter or SAN switches and you need to shutdown one of HBA ports to check server side problem. If the port was a network adapter port, disabling was to easy but what about HBA port on operating system?

Linux Distribution 1

Create Your Own Time Zone in Linux

I don’t know why do you need to create your own time zone in Linux? But I had to customized TZ file and create my own time zone because of what does our application needs? . First lets see that what is TZ and TZ Database. Time Zone Database (TZ Database) The Time Zone Database (often called tz or zoneinfo) contains code and data that represent the history of local time for many representative locations around the globe. It is updated periodically to reflect changes made by political bodies to time zone boundaries, UTC offsets, and daylight-saving rules. Its management procedure is documented in BCP 175: Procedures for Maintaining the Time Zone Database. You can download the latest time zone database from this link: Zone File, UTC Offset, Rule The files are text files and contains the below information about a time zone: Definition of a time zone Daylight saving time (DST) rules Names of time zones Example # Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S Rule US 1918 1919 – Mar lastSun 2:00 1:00 D Rule US 1918 1919 – Oct lastSun 2:00 0 S Rule US 1942 only – Feb 9 2:00 1:00 W # War Rule...

Software Bugs 0

Found EMC Unity Bug on STOR2RRD 2.70

I have published a post about STOR2RRD 2.70 recently and I mentioned many times that this tool is my favorite tool for SAN monitoring. So I’ve updated our servers to the new version but there was a bug which STOR2RRD couldn’t retrieve performance data from EMC Unity systems. What’s Problem? STOR2RRD 2.70 can not retrieve performance data from EMC Unity with different firmware versions. You got the below error on error log of your EMC Unity storage systems (Example log file name: /home/lpar2rrd/stor2rrd/logs/error.log-EMC-UNITY-XXX): What’s The Solution? Recently, STOR2RRD 2.70-1 has been released that includes the fix for issue: stor2rrd-2.70-1.tar Further Reading STOR2RRD 2.70 Is Available Now External Links EMC Unity Performance Data Collector Problem on STOR2RRD 2.70


Change Administrator’s Password for All HPE C7000 Device Bays

HPE C7000 Blade System using Onboard Administrator (OA) KVM module to manage devices and interconnects in chassis. To manage devices directly, OA will redirect to iLO of each device. OA use single sign-on to logon to iLO administration web page. But each server has own administrator user and the user has default password, so if iLO addresses are reachable via network, it’s better to change default password. Think about two or more C7000 chassis with half high blade servers, changing password on 64 servers would be difficult! Onboard Administrator has builtin tool to configure device bays iLO. HPONCFG can change almost all iLO configuration. HPONCFG is also available for different systems and operating systems. Configuration should be as XML format. Example 1: Change Administrator’s Password The below code will change administrator’s password to what you want, just replace “Y0ur Passw0rd” with your password. I’ve tested it on iLO5 and BL460c G10. If you have empty bays, you should run it again after installing new bade server. Also to run on single bay, just replace “all” with bay number. The code must be run via OA, so you should open SSH session to OA module of each C7000 chassis. Example 2:...

Linux Distribution 1

How to Secure SSH Connection on Linux

Why We Should Mitigate SSH Based Attack SSH (Secure Shell) is a most popular remote protocol. SSH allows remote login and execute commands. That providing secure way to login and run commands on remote systems in unsecured networks. Telnet replace with SSH cause of offering more security. But SSH has some weaknesses, in order to reducing SSH based attack, those weaknesses can be mitigated. There is some hardening tips, the tips turn your SSH server into a rock solid communication daemon. Best SSH Hardening Tips In the next minutes, we’ll review 15 solutions from best SSH hardening tips. Each hardening tip will a shield against SSH based attacks. Most of the tips are SSH configurations, some of those tips are different on Linux distributions, so please check the configurations on your distribution documents as well. Also Windows 10 and Windows 2019 have OpenSSH server by adding Win32-OpenSSH to Windows, so read Microsoft documents as well. You must restart SSH server daemon after applying configurations. 1. Custom SSH Port SSH server listening on port 22 by default, so attackers trying to attack your server on port 22. Changing SSH port to another port is a solution to reduce attacks. In order to change...

VNX Domain - Unverified Systems 3

VNX 2 Series: Best Solution to Remove Unverified Systems

VNX Storage arrays can be added to a domain for centralization logging and management for multiple storage arrays. Also Unisphere Central can be added to a VNX domain.

Sometimes, storage administrator makes mistake about adding or removing VNX storage arrays from VNX domain. As an example, administrator has to remove a VNX for send to repairing but forget removing storage array from domain. Another example, when there is multiple domains with multiple range of IP addresses, may be administrator add array to domain wrongly and after that, change IP and add to another domain.

In these situations, domains will contain some systems as unverified system, the unverified systems should verify again and otherwise should be removed.

GSM Community Edition - Report Comparison 4

Virtual Environments Vulnerability Assessment By GSM (OpenVAS) – Part 3

At the first part, we’ve reviewed GSM (Greenbone Security Manager – Formerly OpenVAS) as a security manager or assessment tool for discovering vulnerabilities on virtual environments, the second part was more functional and we talked more about GSM. You leaned that how can you create a target on Greenboone Security Manager and scan it to discover vulnerabilities.

As I said at the end of second part of the blog post, the third part is related to resolving security issues. Any software and specially operating systems have “Hardening Guide”. You must follow steps of hardening guide to reduce security vulnerabilities effect on production environments.