CompTIA Server+ (SK0-005) flashcards

A damaged or improperly terminated network cable can cause intermittent connectivity, signal loss, and erratic link status indicators.

• Common cause of physical layer network issues.
• Can lead to packet loss and reduced throughput.
• Often indicated by unstable link/activity lights.

Memory trick: Cable's the culprit when lights go crazy.

A critical error in the operating system kernel that prevents normal system operation, often leading to a system crash and reboot, indicating a severe software or hardware issue.

• Indicates an unrecoverable system state.
• Can be caused by faulty drivers, corrupted OS, or failing hardware.
• Often points to core hardware issues if software/memory are ruled out.

Memory trick: If the kernel panics and everything's clean, suspect the core hardware's unseen.

Zoning is a SAN security technique performed at the Fibre Channel switch that groups WWPNs into zones, restricting which devices can see and communicate with each other across the fabric.

• Implemented at the FC switch, using WWPNs (or WWNNs)
• Hard zoning enforces at hardware/port level; soft zoning at name-server level
• LUN masking is the complementary array-level access control technique

Memory trick: Zoning is the switch's bouncer, only letting grouped WWPNs into the same VIP room.

The process of securing a server by reducing its vulnerabilities and attack surface.

• Disabling unnecessary services and ports.
• Applying security patches and updates.
• Configuring strong authentication and access controls.

Memory trick: Hardening makes the server tough to crack.

A default gateway is the IP address of the router on a local network that acts as a forwarding host to other networks.

• Essential for communication outside the local subnet.
• Typically the router's IP address on the local segment.
• Misconfiguration leads to 'local only' connectivity.

Memory trick: Gateway is the door to the world beyond your block.

Legacy BIOS with MBR partitioning is limited to 2TB boot volumes; UEFI firmware with GPT partitioning is required to boot from larger drives.

• MBR partition tables limit drives to 2TB (using 512-byte sectors)
• GPT supports drives far larger than 2TB
• UEFI firmware mode is required to boot from GPT system disks

Memory trick: BIOS/MBR hits a 2TB wall; UEFI/GPT breaks right through it.

A hypervisor that runs directly on the host hardware to manage virtual machines, offering high performance and low overhead.

• No underlying host operating system.
• Examples: VMware ESXi, Microsoft Hyper-V, KVM, Xen.
• Ideal for data centers and critical workloads.

Memory trick: Type 1 is bare-metal, Type 2 is hosted, containers are just apps.

The use of multiple, often hot-swappable, fans in a server's cooling system to ensure continuous airflow and prevent overheating even if one or more fans fail.

• Maintains cooling during single fan failure
• Allows hot-swapping for minimal downtime
• Monitored by IPMI or other management tools

Memory trick: Monitor RPMs, clean the dust, replace when faulty, always trust.

In Linux, file and directory access is controlled by ownership (user, group) and permissions (read, write, execute) for the owner, group, and others. Both must be correctly configured for applications to function.

• `chown` changes ownership (user and/or group).
• `chmod` changes file/directory permissions.
• Applications often need write permissions to their log directories or configuration files.
• Security best practice is to grant only the minimum necessary permissions.

Memory trick: Permission Denied? Check who owns the file, then who can read/write!

Errors occurring within a CPU's L1, L2, or L3 cache, indicating a defect in the CPU itself, often leading to system instability, crashes, or unresponsiveness.

• Directly points to a CPU hardware issue.
• Can cause kernel panics or system freezes.
• Requires CPU replacement to resolve.

Memory trick: Cache error in the CPU's domain, means the brain's got a pain.

Techniques used to reduce the risk of exploitation from a newly discovered software vulnerability for which no official patch exists yet.

• Focus on attack surface reduction.
• Implement compensating controls.
• Requires vigilance and proactive measures.

Memory trick: Block the paths, reduce the targets, monitor for anomalies.

Linux uses a permission system based on users, groups, and others, dictating read, write, and execute access to files and directories.

• Permissions are `rwx` (read, write, execute) for user, group, and others.
• Ownership is controlled by the `chown` command.
• Permissions are controlled by the `chmod` command.

Memory trick: Permission denied? User's tied! Change the owner, set it right!

An Uninterruptible Power Supply that continuously powers devices from its inverter, providing seamless, conditioned power and zero transfer time during outages or fluctuations.

• Zero transfer time
• Provides continuous power conditioning
• More expensive than standby UPS units

Memory trick: Online is always on, Standby waits for the light, Line-interactive smooths the ride, Offline is just a fright.

A suite of protocols for securing Internet Protocol (IP) communications by authenticating and encrypting each IP packet of a communication session.

• Operates at the network layer (Layer 3).
• Provides confidentiality, integrity, and authentication.
• Commonly used for VPNs.

Memory trick: IPsec adds a 'shield' to every IP packet.

Ensuring the correct type of network cable is used for 10 Gigabit Ethernet (10GbE) connections to maintain signal integrity, achieve specified speeds, and prevent intermittent connectivity issues.

• Cat5e/Cat6 are generally insufficient for 10GbE.
• Cat6a (or higher) is required for 10GbE over twisted pair copper.
• Fiber optic cables (e.g., OM3/OM4) and DAC cables are common for 10GbE.
• Using incompatible cabling leads to performance degradation or link failure.

Memory trick: Wrong cable type makes 10GbE 'Cranky' and 'Unstable'.

Occurs when two or more applications or services attempt to bind to and listen on the same network port on a single server, resulting in an 'Address already in use' or 'Port in use' error for the second application.

• Only one process can listen on a specific port at a time.
• Common in development environments or when deploying new services.
• Troubleshooting involves identifying the process using the port (`netstat -tulnp` on Linux, `netstat -ano` on Windows).
• Resolution is to change one application's port or stop the conflicting service.

Memory trick: Port's taken! One door, one bouncer, no sharing!

A pre-configured operating system image (e.g., WIM) that includes the OS, drivers, applications, and features, used for automated server deployment.

• Ensures consistency across multiple server deployments.
• Reduces manual configuration time and errors.
• Ideal for 'golden image' scenarios.

Memory trick: Deployment's a journey, custom images smooth the way.

A firewall uses Network Address Translation (NAT) to map public IP addresses/ports to private ones, and Access Control Lists (ACLs) to filter network traffic, allowing specific inbound/outbound connections while blocking others.

• NAT enables private IPs to communicate with public internet.
• ACLs define granular traffic permit/deny rules.
• Essential for securely exposing internal services.

Memory trick: Firewall Filters, Forwards, Forbids

RAID 5 can tolerate a single drive failure. A second drive failure (a 'double fault') within the same array leads to complete data loss.

• RAID 5 uses parity for data redundancy.
• Can withstand one drive failure without data loss.
• Two simultaneous drive failures result in data loss.

Memory trick: Two drives down, data's gone around.

When a newly installed storage device (HDD, SSD) is not recognized by the server's firmware (BIOS/UEFI) or operating system.

• Often due to physical connection issues (cables).
• Could be incorrect BIOS/UEFI settings.
• Less commonly, a faulty drive or motherboard port.

Memory trick: No drive, no show? Check the cables, make it grow!

The process of encoding data to prevent unauthorized access. 'In-transit' encryption protects data as it moves across networks, while 'at-rest' encryption protects data stored on devices.

• HTTPS secures data in transit.
• Full Disk Encryption (FDE) secures data at rest.
• Both are crucial for comprehensive data protection.

Memory trick: Encrypt Everywhere, Every Time

A Microsoft Windows component that allows administrators to view event logs on local or remote machines, providing a centralized location for system, security, and application logs.

• Centralizes various log types.
• Crucial for troubleshooting and auditing.
• Includes Application, Security, and System logs.

Memory trick: Events Show Everything

Active Directory relies heavily on DNS for service location (SRV records), name resolution, and authentication, making correct DNS configuration critical for domain operations.

• Domain controllers register SRV records in DNS.
• Clients use DNS to find DCs for authentication and services.
• Incorrect DNS settings prevent domain join and logon.

Memory trick: DNS is the map to the domain's door.

In Windows, network share access requires both Share permissions (controlling who can connect to the share itself) and NTFS permissions (controlling what they can do with files/folders within the share). The most restrictive permission applies.

• Share permissions are applied first when accessing over the network.
• NTFS permissions are applied second and control granular file/folder access.
• Local access only uses NTFS permissions.
• Troubleshooting 'Access Denied' for network shares requires checking both sets of permissions.

Memory trick: Share Permissions are the 'Gatekeeper', NTFS are the 'Room Keys'!

The gradual accumulation of access rights by a user over time, often due to job role changes, without corresponding permission removals.

• Violates the principle of least privilege.
• Increases security risk by granting unnecessary access.
• Mitigated by regular access reviews.

Memory trick: Regular checks keep privileges tight.

HTTPS (Hypertext Transfer Protocol Secure) is the secure version of HTTP, which uses SSL/TLS for encrypted communication over TCP port 443.

• Encrypts web traffic
• Requires SSL/TLS certificates
• Standard port is 443

Memory trick: Ports are like doors, each leading to a specific server service!

A data center cooling strategy where the cold aisle (where server intakes are located) is enclosed to prevent cold air from mixing with hot exhaust air, ensuring that servers receive a consistent supply of cool air.

• Isolates cold air from hot air.
• Improves cooling efficiency.
• Reduces hot spots and temperature differentials.
• Typically involves physical barriers (panels, doors) around the cold aisle.

Memory trick: Contain the Cold, Control the Heat, Conserve Energy.

A RAID level that stripes data across multiple disks and distributes parity information among all disks. It provides fault tolerance against a single drive failure and offers a good balance of performance, capacity, and redundancy.

• Requires a minimum of 3 drives.
• Usable capacity is (N-1) * drive_size.
• Tolerates a single drive failure.
• Good for general-purpose server storage where capacity and single-drive redundancy are key.

Memory trick: RAID 5: Five's the Sweet Spot for Space and Safety.

Components (e.g., trays, ducts, rings, ties) used within server racks and data centers to organize, route, and protect cables, which improves airflow, simplifies identification, and eases maintenance.

• Reduces cable clutter.
• Improves airflow and cooling efficiency.
• Simplifies troubleshooting and maintenance.
• Protects cables from damage.

Memory trick: Organized Cables Create Calm, Clear Connections.

A type of twinax copper cable that provides high-speed, short-distance connectivity between network devices or servers and storage, often used as a cost-effective alternative to fiber optic transceivers for intra-rack connections.

• Copper-based twinax cable.
• Used for short distances (typically up to 7-15 meters).
• Commonly supports 10GbE, 25GbE, 40GbE, 100GbE.
• Cost-effective for intra-rack connections.

Memory trick: Direct Attach Cables Deliver Data Quickly, Close By.

A type of Uninterruptible Power Supply (UPS) that continuously converts incoming AC power to DC to charge its battery, then converts it back to AC power for the connected devices. This provides continuous, clean power and isolates the load from all input power fluctuations.

• Provides continuous, clean power (zero transfer time).
• Protects against all nine common power problems.
• Most expensive UPS type.
• Ideal for critical servers and sensitive equipment.

Memory trick: Online UPS: Always On, Always Perfect Power.

A nested RAID level that combines RAID 1 (mirroring) and RAID 0 (striping). It provides excellent performance, high fault tolerance (can withstand multiple drive failures), and is often recommended for applications requiring high I/O, such as databases.

• Requires a minimum of 4 drives.
• Combines mirroring (fault tolerance) and striping (performance).
• Can tolerate the failure of multiple drives, as long as they are not in the same mirrored pair.
• High cost per usable gigabyte but offers superior performance and redundancy.

Memory trick: RAID 10: One-Zero for Supreme Protection and Speed.

A modern firmware interface that replaces the traditional BIOS. UEFI provides enhanced capabilities such as support for large hard drives (GPT), faster boot times, secure boot, and a more flexible pre-boot environment, often with a graphical interface.

• Replaces Legacy BIOS.
• Supports GPT partition tables (drives > 2TB).
• Enables Secure Boot for enhanced security.
• Offers a more advanced and extensible pre-boot environment.

Memory trick: UEFI: Unified, Extensible, Future-Proof Firmware.

A type of server memory module that uses a buffer to reduce the electrical load presented to the memory controller. This allows servers to support a greater number of DIMMs per channel and achieve much higher total memory capacities than with RDIMMs.

• Employs a dedicated buffer chip (not just a register).
• Enables highest possible memory capacities in servers.
• Reduces electrical load on the memory controller.
• Typically used in high-end enterprise servers and virtualization hosts.

Memory trick: LRDIMMs Load-Reduce for Limitless RAM.

Two or more PDUs in a rack, each connected to an independent power feed, designed to provide continuous power to servers with redundant power supplies. This setup eliminates a single point of failure in the power distribution path.

• Requires servers with redundant PSUs.
• Each PDU connects to a separate power circuit/feed.
• Ensures power continuity if one PDU or feed fails.
• Key component of a highly available power infrastructure.

Memory trick: Redundant PDUs: Power Done Right, Double the Might.

The process of individually testing RAM modules to identify a faulty stick or slot when experiencing memory-related issues.

• Symptoms: BSODs, application crashes, system instability.
• Method: Test one module at a time or swap modules between known good slots.
• Tools: Memory diagnostic tools, physical swapping.

Memory trick: When memory is 'crashing', 'isolate' and 'test' each 'stick'.

The process of identifying and removing unnecessary files from a Linux filesystem to free up disk space.

• Common culprits: `/var/log`, `/tmp`, old package caches.
• Tools: `du`, `df`, `find`, `rm`.
• Prioritize non-critical, easily removable files.

Memory trick: When your disk is full, first 'sweep' out the 'trash', then consider 'growing' or 'moving'.

A local firewall on a server can block specific outbound or inbound connections for applications, leading to connection timeouts or failures.

• Often configured per-application or per-port.
• Can be Windows Firewall, iptables, or third-party software.
• Troubleshoot by checking firewall logs or temporarily disabling for testing.

Memory trick: When an app can't connect, check the path, especially the gatekeeper.

Configuration drift is the gradual, unintended divergence of a system's configuration from its original baseline or desired state over time.

• Can introduce security vulnerabilities.
• Makes troubleshooting more difficult.
• Regular auditing helps detect and mitigate it.

Memory trick: Drifting configurations can cause a server's security to suffer a 'drift' in quality.