Tech Tips

Tech Tips

Field notes on monitoring, infrastructure, and keeping systems reliably boring.

The LDAP and identity writing moved to ldapguys.com. What's here is monitoring, security and operations.

Preparing for IT Disasters: Identifying Weaknesses and Conducting Effective Drills

Disaster can strike at any time, and you need to be prepared. This article will give some tips on how to identify and eliminate weaknesses in your IT systems …

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Best practices: Securing Passwords in Command-Line Operations

When working with command lines that require passwords, such as using ldapsearch, it’s crucial to manage these credentials securely. Storing passwords directly …

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Why Offline Backups Are Needed

Here at Rex Consulting, Inc. we have multiple virtual machines running a myriad of different services. With the hypervisor and a secondary server managing the …

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Checking TLS/SSL Services with Check SSL Cert

Check SSL Cert Matteo Corti created a great shell script that can be used for TLS certification that enhances Nagios monitoring tools. The repo for the project …

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Checking TLS/SSL Services with Nagios Service Checks

A TLS (or SSL) certificate expiration should never be the cause of an outage, but we’ve all heard about this happening before. If it does happen, it usually …

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Managing Host Removals In Nagios XI

A client recently asked me what is the best way to remove Nagios XI object definitions for hosts that have been retired. Well there’s a few ways to accomplish …

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Rex To Offer Basic Linux Training Classes Soon

Rex Consulting is working on a curriculum for some technical training classes. We’re starting with Basic Linux Training. My main motivation here is that I want …

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Wanting Better Monitoring, Just After A Disaster Strikes

The man who is a pessimist before 48 knows too much; if he is an optimist after it, he knows too little. - Mark Twain We often hear from people who want better …

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Using Duo 2FA To Improve Security In Nagios XI

Starting with version 5.5, Nagios XI has implemented 2 factor authentication using DUO. DUO 2FA improves the security for Nagios XI by letting users log in …

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An Introduction To Nagvis

Nagvis is a visualization utility that is included in all Nagios XI installations. As it’s name suggests, Nagvis can create dynamic visualizations of almost all …

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Automating Firewall Block Rules For Malicious Attackers With Nagios Logserver And OpenBSD

While Nagios Logserver is a useful tool for system analysis and central log management, it is also a great tool to analyze network security. One can actually …

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Phone (Telecom) Phishing

We received a call today to our main business line from someone who asked to “speak to the person who handles Worker’s Comp. Insurance.” The call routed to our …

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NSClient++ With Signed SSL Certificates And Strong Encryption

By using NSClient++ with Signed SSL Certificates and strong encryption, you can guard your monitoring traffic against eavesdroppers. If you are using NSClient++ …

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Nagios Event Handlers: Self-Healing And More

For self-healing in IT operations, Nagios event handlers are a great way to go. Event handling scripts can be written to restart services that die, which is a …

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Merging Multiple Nagios Check Outputs Using Macros

Macros in Nagios are a powerful tool. There are countless (see link) macros in existence that allow users to obtain Nagios check data easily. Among such macros, …

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Checklists Plus Good Monitoring = Reliability

SYSTEM HEALTH CHECKLISTS + GOOD AUTOMATED MONITORING WILL DRASTICALLY INCREASE THE RELIABILITY OF YOUR SYSTEM. The use of checklists in order to increase the …

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The WMI Plus File Checks

The WMI Plus nagios plugin (found at http://www.edcint.co.nz/checkwmiplus/?q=overview) is an agentless ‘agent’ that comes with several different built in …

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Applying Double Filters In NXLOG For Windows Event Logs

In our previous NXLOG article, it was mentioned how it was possible to create filters by using the Exec drop() directive in NXLOG accompanied by a filtering if …

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Adding An Additional Layer Of Filtering Through NXLOG

Have you ever wanted to apply an additional filtering layer to your logs before sending them to Nagios Log Server (NLS)? If you have are sending streams of logs …

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Two Easy Ways To Increase Email Security & Legitimacy For Your Domain

HERE IS TWO EASY WAYS TO INCREASE EMAIL SECURITY AND LEGITIMACY FOR YOUR ORGANIZATION AND DOMAIN. USE Sender Policy Framework (SPF). SMTP, the email protocol in …

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Nagios Monitoring: Planning Is The Hallmark Of Intelligence

“PLANNING IS THE HALLMARK OF INTELLIGENCE” With Nagios Monitoring implementations, “Planning is the Hallmark of Intelligence”. Actually I borrowed that phrase …

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Tip: Destroy Expire SSH And SSL Keys

Be sure to delete expired SSH and SSL keys that you no longer use. If someone is capturing your encrypted data and saving it somewhere, they would be able to …

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Best Practice: Privilege Separation In Monitoring Agents

It is a Best Practice to run monitoring agents with privilege separation. This means that the user ID that you run the monitoring agent should be a different …

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Monitoring Systems And Discipline

If you have a monitoring system, for maximum effectiveness, you need to be disciplined about handling alerts. “Handling alerts” means either A) fixing the …

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Jython Monitoring JMX and Java Applications

Jython, an implementation of python which runs on java, is a great tool to use to access java applications thru JMX and directly calling java classes. We wrote …

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Nagios Monitoring Check Resolution

When constructing new checks for Nagios, sometimes it’s worthwhile to consider what we’ll call “check resolution”. What we mean by this term is how many …

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Hackers Don't Holiday

Hackers don’t holiday. I know of a client, who, a couple years ago, was hacked right around the time that Santa was delivering gifts. Which, needless to say, …

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Year End Reminder On Password Changing & Email Forgery Phish Prevention Tips

Since we’re nearing the end of the year, I thought it’d be a good idea to remind the world to change their passwords. Also I want to provide some tips on phish …

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Tricks: Apache Cassandra Monitoring Tricks With The Help Of JMX And Nagios

If you run Apache Cassandra, you can monitor it with the help of Nagios and JMX. Apache Cassandra has come to “change the world”, I was told at the Cassandra …

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"Heartbleed", Internet Security And "The Internet Of Things"

The “HeartBleed” bug is a huge crisis for Internet Security and “The Internet of Things”. The past 15 years of progress in the computing and internet world have …

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DST: Bad For Tech

Daylight savings time is probably to blame for a decent percentage of technology related problems, especially the first week of November and the second week of …

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What's Your Threat Model?

Do you have a security threat model in place? What’s a security threat model? When we talk about security threat model, it means that we discuss, document, and …

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Environment Awareness And The Application Health Monitoring Spreadsheet

THE APPLICATION HEALTH MONITORING SPREADSHEET - HOW GOOD MONITORING AND REGULAR AUDITING CONTRIBUTES TO A BETTER ENVIRONMENT AWARENESS It might be redundant to …

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Tip: Centralized Logging Benefits

Centralized logging benefits more than just application troubleshooting. Today, many organizations are required to comply to regulatory standards like HIPAA, …

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Tip: Validation Best Practice

Validation best practice is an important topic that is often not given the importance it is due until it is too late. It is skipped by the undisciplined, …

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Tip: Finding The Right Deployment Pace

When I was young I built model airplanes. The instructions were usually simple, clear, and easy to follow. I was eventually able to build some cool looking …

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Trick: New Graymail Blocking Feature

We offer a new Graymail Blocking Feature which blocks mail not considered spam, yet is still a nuisance to recipients. Some of these types of email include …

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Tip: Design Operation-Ready Solutions

Design operation-ready solutions so that your solutions will run well in production. If you hire someone to recommend, design, and implement solutions in your …

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Nagios For Application and System Monitoring

Nagios is the premier monitoring application. Like a swiss-army knife, Nagios is highly versatile and extensible, and works very well for monitoring the health …

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Tip: Better Application Logging

Good application logging is invaluable to a well-functioning application team. From troubleshooting problem incidents to collecting and plotting performance …

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Tip: Timezones: Always Set Your Servers To GMT

It rarely makes any good sense to set a server to a timezone other than GMT. GMT is the best practice for the following reasons: You don’t have to worry about …

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Tip: Password Management Best Practice: Tiered Passwords

With the recent password database break-ins at some very high-profile companies, those whose passwords were exposed should change their passwords, and consider …

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Tip: Java Does Not Honor DNS TTL; Recommendation in Enterprise Environment

When using the java/JVM DNS caching, you should know that java caches DNS entries by default, which is abnormal for most client and server applications. It also …

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Who Did What? Privileged Execution, and How No-Password Accounts (Even For Root) Help You Achieve This

Privileged account access is a sensitive thing today, especially with all the compliance and regulations requirements built into most corporate information …

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Opportunistic vs. Required TLS

TLS is Transport Layer Security, the public version of the SSL protocol originally developed by Netscape. It’s used today to secure many client server …

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Tip: Good Application Monitoring and Alerting Saves Money and Promotes Health

A good application monitoring alerting system significantly increases the reliability and reduces the amount of work that needs to be done to operate a client …

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Tip: Think Before Using San Technology

In many situations, it is difficult recommend SAN technology. The advantages of central management, ease of backup, better disk utilization are clear, but …

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