Tag: networking

Oracle Cloud Infrastructure 2023 Architect Associate Study Resources

by Samuel Mitchell, posted in architecture, Oracle Cloud Infrastructure

I have created this blog to share resources used to prepare for my Oracle Cloud Infrastructure Architect Associate Exam. The exam will be done using Online proctoring which will be my first time. Unfortunately, I am unable to take advantage of the test center option because it is not available using the Race to Certification program. As a result, I end up scheduling the exam at my work office because I have no proper enclosed sound proof room in my house to do a proctored exam.

Exam Number: 1Z0-1072-23

https://education.oracle.com/oracle-cloud-infrastructure-2023-architect-associate/pexam_1Z0-1072-23

https://mylearn.oracle.com/ou/learning-path/become-an-oci-architect-associate/122195

Passing this exam is required to earn these certifications. Select each certification title below to view full requirements.
Oracle Cloud Infrastructure 2023 Certified Architect Associate

Exam Format: Multiple Choice

  • Duration: 90 Minutes
  • Exam Price: $245 
  • Number of Questions: 55
  • Passing Score: 65%
  • Validation: This exam has been validated against Oracle Cloud Infrastructure 2023
  • Policy: Cloud Recertification

Review exam topics

The following table lists the exam objectives and their weightings.

Objectives% of Exam
Compute20%
Networking28%
Storage22%
Observability and Management8%
Identity and Access Management10%
Security12%

Compute [20%]

  • Select appropriate computing choices
  • Configure compute instances
  • Configure Autoscaling
  • Describe OCI compute image options
  • Describe and configure OS Management
  • Understand Infrastructure Maintenance

Networking [28%]

Storage [22%]

Observability and Management [8%]

  • Understand Observability and Management platform
  • Configure Monitoring and set alarms
  • Configure Logging

Identity and Access Management [10%]

  • Understand AuthN and AuthZ
  • Implement compartments
  • Implement conditional and advanced policies
  • Configure Dynamic Groups and Tag based access control

Security [12%]

VMware VCP 6.7-DCV – Objective 1.4 – Differentiate between NIOC and SIOC

by Samuel Mitchell, posted in VMware

The following notes will assist you to prepare for this objective:

  • This objective is about managing noisy neighbors!
    • NIOC for network & SIOC for storage
  • You need to demonstrate understanding of
    • What dimensions you can control and applied-to
    • Limitations of service
    • Pre-reqs for implementation
  • Foundation knowledge of proportional share allocation is expected
    • What does low, medium & high mean?
    • What happens when you use numbers instead of labels?
    • How does the power on of another VM affect share allocation?

Reference:

vSphere Resource Management Guide pdf – Chapter 9-Managing Storage I/o Resources

vSphere Networking Guide pdf – Chapter 11 – vSphere Network I/O Control

Computer blocked by Port Security

by Samuel Mitchell, posted in Cisco, Microsoft, Routing & Switching, Security

My colleague was working on an issue where a computer was communicating on the network through a Cisco switch that had port security enabled. As usually, he disables port security and re-enables it in an attempt to get the new mac address registered on the port. The computer (A) was now able to get an IP address from the DHCP server but unfortunately, the computer (A) still was not able to communicate with the server. In an effort to identify whether the problem was with computer (A) or the network port, another computer (B) was connected to the port which was successful. But when computer (A) was reconnected to the same port, there was still no communication. All network settings on Computer (A) were verified to be correct but still no break through. The same computer (A) was taken to another switch in another location and surprisingly it worked. So hhhmmm….what could be the problem? It was escalated to me to investigate further as he could not identify what was the root of the problem.

I started to ask the question “What is working?”

The responses were:

  1. Other devices were communicating when connected to the port
  2. The computer (A) is getting an IP address from the DHCP server
  3. The computer (A) is able to communicate on other switches

Next question, did they try the computer (A) on another port on the same switch? Response was No.

Anyways, everything was connected back to how it was before and then I started the troubleshooting.

The following observations were made:

  1. Port-security was enabled on the entire switch but disabled on this troubled port.
  2. The port duplex and speed was ok (Full/100)
  3. The computer (A) got an dynamic IP address from the DHCP server
  4. The computer (A) mac address was not showing on the port when I check the MAC address table for the problem port (f0/42)
  5. Port security sticky address listing showed that computer (A) mac address was tied to port f0/22

What do you think the root of the problem is?

The computer (A) is not able to communicate with anything on the network because the mac address of the computer (A) was tied to another port so when devices response to the packet, it is returning to the wrong port. so the solution was to remove the sticky address and allow the switch to relearn it over the new connected port (f0/42). Another question resonate in my mind was “How did it get an IP address from the DHCP server?”. But if you review how devices acquire an IP address, it is using broadcast. Therefore, the computer will always get an IP address but it would not be able to communicate with other devices.

I hope this troubleshooting scenario helps someone with understanding port-security on a Cisco switch.

VCP65-DCV – Objective 7.2 – Troubleshoot vSphere Storage and Networking

by Samuel Mitchell, posted in VMware

The following reference material from the vSphere 6.5 online documentation will assist you in covering the main information that is needed to know the topics in this objective:

  1.  Know the commands
    1. esxtop
  2. Create a Datastore Cluster
  3. Setting the Aggressiveness Level for Storage DRS
  4. Troubleshooting Networking
  5. Troubleshooting Storage
  6. VMFS metadata Updates