From the net: How to Simulate Network Outages

Simulating network outages is an important step in validating highly available and/or redundant network configurations. Along with validation, another use case for simulating network outages is to test the resiliency of mission-critical systems and applications. The simplest example of a test-driven network outage is to turn off the primary uplink connection of a dual-homed router and analyze the results. With appropriate tools, you can verify that the network traffic quickly re-converges to the secondary link with minimal packet loss. In more complex scenarios, the network simulation may need to introduce packet loss, increase in round-trip time, bandwidth saturation, DNS and DHCP failures. To implement these failure scenarios there are different tools that can do the job. I’ll briefly review some of them, particularly the open source solutions.

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One of the best giveaways that I've ever received. 

From our Wireshark/Profitap class a while back https://packetguru.com/ 

Thanks John

Rii RK100+ Multiple Color Rainbow LED Backlit Large Size USB Wired

Why Every IT Troubleshooter Should Carry a Portable LCD Display

 

When you’re deep in the field troubleshooting hardware or network equipment, one tool that often goes underappreciated—but can save the day—is a portable LCD display. Many devices such as servers, switches, or embedded systems output critical data or BIOS messages directly to a display, and without one on hand, you might find yourself blind to what’s really happening. A compact LCD lets you instantly see console outputs, error codes, or configuration prompts without waiting for someone else to bring one or trying to guess what the LEDs are telling you.

Portability is the key advantage here. Modern LCDs are lightweight, slim, and powered through USB or battery packs, making them easy to slip into your toolkit or backpack. When you’re on-site, especially in tight server rooms or industrial areas, you don’t have the luxury of hauling a full monitor around. Having your own display means you can plug in, verify, and get results fast—whether it’s a headless system, a router with a misconfigured interface, or a piece of lab gear showing diagnostic information.

Carrying your own display also means independence and preparedness. You’re not relying on the client’s equipment or waiting for someone to find a monitor in a dusty back room. You can confirm system states, troubleshoot POST issues, and even make quick BIOS or bootloader changes on your own terms. It’s a small investment that pays off big in time saved and professionalism demonstrated.

In short, a portable LCD display transforms how you handle unknown or unresponsive systems. It’s like having an extra pair of eyes in your toolkit—ready whenever the situation turns unpredictable. Whether you’re configuring switches, diagnosing embedded devices, or recovering from boot failures, this one tool keeps you in control and keeps your troubleshooting momentum going strong.

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from the net: Linux Grep

 Everyone loves a reference sheet and this one is very helpful since GREP is so under utilized

 

Found this on www.sysxplore.com

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my favorite mouse - click on the image for more info

Logitech M720 Triathlon Wireless Mouse, Bluetooth, USB Unifying Receiver, 1000 DPI, 6 Programmable Buttons, 

-20% $36.08

List Price: $44.99

blast from the past: The IBM 3800 Laser Printer

 

The IBM 3800 Printing System, introduced in 1976, was a landmark in computer printing technology and is often regarded as the world’s first commercial laser printer. Designed primarily for high-volume data centers, the 3800 combined a laser imaging system with electrophotographic technology (similar to photocopying) and continuous-form paper feeding. It could print at an impressive rate of 20,000 lines per minute—roughly equivalent to 110 pages per minute—making it a revolution in automated document generation for large organizations like banks, insurance companies, and government agencies.

When it first launched, the IBM 3800 came with a hefty price tag. Depending on configuration and options, the system cost between **$250,000 and $500,000 USD** (equivalent to over $1 million today). However, IBM typically leased such machines to clients rather than selling them outright. This business model made sense for large-scale enterprise operations that required regular maintenance, consumables, and software integration. The printer’s cost was justified by its efficiency—it could replace multiple impact line printers and drastically reduce downtime and operating costs in large-scale print operations.

The 3800 also introduced several important innovations in digital printing. It was the first printer to take input directly from digital computer data, rather than relying on preformatted line print files, allowing for dynamic page layout and improved typographic control. The printer supported fonts and graphics stored in memory, a feature that paved the way for later desktop laser printers in the 1980s. Its use of continuous-form paper and integrated fuser technology made it highly reliable for round-the-clock operation, which was essential for industries producing daily billing statements or reports.

As for trivia, the IBM 3800 was so large it required its own dedicated room and environmental controls—it resembled more of a small car than a modern printer. It was also one of the first machines to use a **laser beam controlled by computer logic** to create images on a photoconductor drum, a concept that later became standard in laser printing. IBM continued developing the series through the 1980s, leading to successors like the 3800 Model 3, which improved resolution and reliability. Interestingly, some units remained in use well into the 1990s, a testament to their engineering quality and durability. The IBM 3800 is now remembered as the ancestor of modern laser and page printers, marking a major milestone in the evolution of digital printing technology.

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one of my favorite portable keyboards

Passive Discovery with Wireshark: Finding Devices the Safe, Quiet Way

Wireshark is an ideal tool for passive device discovery because it listens without touching the network — no probes, no ARP scans, no extra traffic that could disturb production systems. When you capture traffic at a mirror/span port or on an access point, Wireshark reveals the network “chatter” devices already send: discovery protocols (CDP/LLDP), DHCP exchanges, ARP, mDNS, and more. In your example, capturing a CDP packet from a Cisco switch instantly gave you device-identifying information (device ID, platform, capabilities) and the management IP address advertised in the CDP Address TLV — all without logging into the device or changing network state. That makes passive discovery low-risk and stealthy, especially useful in sensitive or stable environments where active scanning is unacceptable.

Beyond safety, passive captures give richer context than simple ping sweeps. A single CDP/LLDP frame can include the switch model, root/neighbor relationships, VLAN and port identifiers, and the management address — data that helps you map topology precisely. Wireshark’s decoders present those TLVs in human-readable form and you can quickly build an inventory: which switches are where, which devices advertise PoE capabilities, and which ports connect to what. Because you observe real traffic, you also learn about timing and frequency (how often devices advertise themselves), and you can correlate discovery with DHCP or ARP to see which IPs correspond to which MACs and which clients are actually active.

Finally, passive discovery with Wireshark aids troubleshooting, security and forensics. If a new, unexpected device appears on the network you can inspect the capture to see how it identified itself (hostname, vendor OUI in the MAC, CDP/LLDP info), whether it requested an IP via DHCP, and what services it announced. That speeds incident response and root-cause analysis. A short practical tip: apply display filters like `cdp` or `lldp` to quickly find discovery protocol frames, and expand the Address/Device-ID TLVs in the packet details pane to copy the management IP shown in the CDP packet. Always remember to capture only where you’re authorized to and respect privacy and policy when monitoring networks.

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I LOVE Network Testing Ep 8 - Beyond Wire Map Testing. Understanding Qual, Cert, & Bit Rate Testing for Copper Networks