Router Basics: The Lost Configuration
I was inspired to put together videos that covered basic networking skills last year, while working with an install team as a lead technician. Everyone on the team had a different level of experience, which is always a challenge.
For example, when I asked someone to retrieve a backup router and reconfigure it, I was told that there something "weird" with the replacement router. When I asked what was wrong, the admins explained that even though they configured the router, the router was ignoring it. I understood right away what the problem was; it's a common one that can trip up inexperienced IT admins. When a router is rebooted or loses power, it can lose the configuration you set. In this video, I demonstrate the problem.
I explained to the install team that some people set the configuration registry to ignore the configuration when storing equipment. Using the show version command, I showed them that the registry was set for 0x2142, which tells the router to ignore the startup configuration. I then used the show startup-config command to prove that the configuration was indeed there. I revealed that the solution is to write config-register 0x2102.
When we reloaded the router, the configuration was no longer ignored. Cisco explains this issue in more detail in a troubleshooting tip.
I always try to figure out if equipment I use is susceptible to this problem in case I ever run into it.
As an aside, when it comes to getting familiar with configuration commands in a Cisco environment, you don’t even need to have the physical equipment. You can use Cisco’s Packet Tracer software to run tests on a simulated network without fearing that you may mess something up.
Recommended For You
Low-Power WANs offer an alternative to 5G for connecting a fast-growing array of basic devices and sensors that transmit small amounts of data.
An effective network visibility strategy requires understanding the technical, financial, political, and legal aspects impacting your network operations.
Emerging organizational structures for IT include placement of IT pros in user areas and departments forming their own "micro IT's."
Comparing a good and bad trace helps identify performance issues. Dynamic baselining can be used when you do not have a good trace to reference.
Combining commodity server platforms and FPGA-based SmartNICs will allow network applications to operate at hundreds of gigabits of throughput with support for millions of simultaneous flows.
SD-WAN implementations are on the rise thanks to the potential cost savings, increased network resiliency, and better application performance they deliver.