How Do You Troubleshoot “TLS Error: TLS key negotiation failed to occur TLS handshake failed”?

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Problem scenario
You have a Linux server with the openvpn binary command installed. You try to start the OpenVPN client service. You see this message: “TLS Error: TLS key negotiation failed to occur TLS handshake failed.”

What should you do?

Solution
Reinstall and reconfigure the OpenVPN server. Just completely start over.
You may want to try this: https://www.cyberciti.biz/faq/howto-setup-openvpn-server-on-ubuntu-linux-14-04-or-16-04-lts/

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Is It a Best/Recommended Practice to Use AWS VPC Peering Connections?

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Problem scenario
You have heard about AWS VPC Peering Connections. Should you use them?

Solution
The short answer is “yes.”

Some “best practices” for VPCs are merely step-by-step directions for setting it up while describing options that you may or may not want to take. This posting, on a technical blog of a large reputable company,

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How Do You Get the Internet and/or NIC on Your Windows Workstation to Work?

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Problem scenario
You rebooted your Windows laptop. You are not getting any network. The internet is unreachable. The NIC’s lights are off. What should you do?

Possible Solution #1
Use WiFi. Completely bypass your network interface port.

Possible Solution #2
1. Reboot your computer.
2. Press Esc to enter the Startup Menu.
3.

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How Do You Troubleshoot SSH Connection Timed Out?

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Problem scenario
You are trying to use SSH, but you get a “connection timed out” error. What should you do?

Possible solution #1
Can you try to ping the hostname or IP address? Are you connected to a necessary VPN? Perhaps the endpoint is down or not reachable from the network you are on.

Possible solution #2
Is there a router that was recently configured?

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What Can Cause an Application to Run Slowly?

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Problem scenario
You support an existing application and its servers. It is experiencing slowness as the users are complaining about its performance. What are some potential root causes of this slowness?

Possible Solutions

  • The slowness is caused by the client. A user’s workstation has something wrong with it (e.g., malware, or it is trying to run too many applications at once).

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What Is The Difference between a VPC and a Subnet?

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Question
You have heard about VPCs and subnets. What are the differences between these two?

Answer
A subnet is a subdivision of a network. Internal to an enterprise network, you may divide the network into different addresses with gateways, routers, bridges and subnet masks. The subnet mask (in CIDR (classless inter-domain routing) notation may be /28, /24, /10 etc.

A VPC ordinarily has its own NACLs and firewalls associated with it;

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How Do You Troubleshoot Discrepant nmap Results Based on The sudo Command?

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Problem scenario
You are using nmap. You try the exact same command with sudo and without sudo. Why are these commands providing different results?

Here are examples of running the exact same command, once with “sudo” and once without:

jdoe@ciserver:~$ sudo nmap -p 9090 192.168.2.25
Starting Nmap 7.80 ( https://nmap.org ) at 2022-01-05 09:56 EST
Nmap scan report for 192.168.2.25
Host is up (0.00056s latency). …

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How Does an ssh Command Work in Detail?

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Question
You want an overview of how SSH works because it seems confusing. You want to comprehend how it works or know exactly what happens when you run an SSH command like ssh jdoe@acme.com. Where can you find a precise explanation on using ssh as well as some background information on SSH?

Solution
SSH is named after the secure shell way of remotely connecting to another server using encryption.

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Are Zero Trust Networks More Secure than VPN-Protected Networks?

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Question
Some companies are getting away from VPNs in favor of zero trust systems. It can help save money on bandwidth and facilitate a better network performance when every employee is working remotely. Are NoVPN Services More Secure for a Given Enterprise? Is it recommended to use non-VPN services?

Answer
We think this is a debatable whether VPNs (Virtual Private Networks) make systems more secure.

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