Networking interview questions

1. A.a per-host virtual switch
2. B.A virtual switch security setting that lets a vNIC see all traffic on the port group, needed for nested hypervisors and packet sniffers
3. C.A template on a virtual switch defining VLAN, security and teaming policy for the VMs connected to it
4. D.A hypervisor-level firewall (NSX, Flow) that enforces policy on each vNIC, enabling microsegmentation without hairpinning through a physical appliance

Answer + AI explanation with Pro

1. A.VGT mode
2. B.LLDP and CDP
3. C.TSO and LRO offload
4. D.Standard vSwitch

Answer + AI explanation with Pro

1. A.Standard vSwitch — A vDS capability that dynamically learns guest MAC addresses on a port, required to support nested ESXi and multiple MACs behind one vNIC
2. B.Standard vSwitch — a per-host virtual switch
3. C.Standard vSwitch — vDS rules that allow, drop, or DSCP/CoS-tag packets at the port group level for security and QoS.
4. D.Standard vSwitch — Link-layer discovery protocols that map virtual switch uplinks to physical switch ports and VLANs.

Answer + AI explanation with Pro

1. A.Allocates distributed switch bandwidth to traffic types (vMotion, vSAN, VM) using shares, limits, and reservations.
2. B.Policies like route-by-port-ID, source-MAC-hash, or IP-hash (required for static EtherChannel) spread uplink traffic.
3. C.Active ports initiate LACP negotiation; passive only respond, so at least one side must be active to form a bond.
4. D.a virtual switch managed centrally by vCenter across hosts

Answer + AI explanation with Pro

1. A.Private virtual switch
2. B.vDS health check
3. C.Distributed vSwitch (vDS)
4. D.Standard vSwitch

Answer + AI explanation with Pro

1. A.Distributed vSwitch (vDS) — Policies (route based on originating port, source MAC, or physical NIC load) that distribute VM traffic across multiple uplinks for bandwidth and redundancy
2. B.Distributed vSwitch (vDS) — Link-layer discovery protocols that map virtual switch uplinks to physical switch ports and VLANs.
3. C.Distributed vSwitch (vDS) — a virtual switch managed centrally by vCenter across hosts
4. D.Distributed vSwitch (vDS) — A virtual switch security setting that lets a vNIC see all traffic on the port group, needed for nested hypervisors and packet sniffers

Answer + AI explanation with Pro

1. A.VLAN tagging applied by the vSwitch per port group
2. B.A template on a virtual switch defining VLAN, security and teaming policy for the VMs connected to it
3. C.Larger frames cut per-packet overhead for storage and vMotion; MTU must match end-to-end across the path.
4. D.a virtual switch managed centrally by vCenter across hosts

Answer + AI explanation with Pro

1. A.VGT mode
2. B.VST mode
3. C.TSO and LRO offload
4. D.Private virtual switch

Answer + AI explanation with Pro

1. A.VST mode — Verifies VLAN, MTU, and teaming consistency between the distributed switch and physical switch ports.
2. B.VST mode — VLAN tagging applied by the vSwitch per port group
3. C.VST mode — The Data Plane Development Kit: userspace poll-mode drivers that bypass the kernel network stack for line-rate packet processing in NFV virtual switches
4. D.VST mode — A virtual network adapter presented to a VM (e.g. VMXNET3, virtio-net) that connects to a virtual switch port

Answer + AI explanation with Pro

1. A.VLAN 4095 trunk where the guest OS handles 802.1Q tagging
2. B.a virtual switch managed centrally by vCenter across hosts
3. C.a Hyper-V switch giving VMs and host access to the physical network
4. D.A vDS feature subdividing a VLAN into promiscuous, isolated and community secondary VLANs to restrict guest-to-guest traffic within a subnet

Answer + AI explanation with Pro

1. A.Port mirroring (SPAN)
2. B.DPDK
3. C.VST mode
4. D.VGT mode

Answer + AI explanation with Pro

1. A.VGT mode — Remote Direct Memory Access over Converged Ethernet lets hosts move data with minimal CPU and latency, used for vSAN, SMB Direct and live migration
2. B.VGT mode — A virtual network adapter presented to a VM (e.g. VMXNET3, virtio-net) that connects to a virtual switch port
3. C.VGT mode — VLAN 4095 trunk where the guest OS handles 802.1Q tagging
4. D.VGT mode — Verifies VLAN, MTU, and teaming consistency between the distributed switch and physical switch ports.

Answer + AI explanation with Pro

1. A.a Hyper-V switch giving VMs and host access to the physical network
2. B.VLAN 4095 trunk where the guest OS handles 802.1Q tagging
3. C.A vDS feature subdividing a VLAN into promiscuous, isolated and community secondary VLANs to restrict guest-to-guest traffic within a subnet
4. D.A hardware feature where one physical NIC exposes multiple virtual functions assignable directly to VMs, bypassing the virtual switch for low latency

Answer + AI explanation with Pro

1. A.VGT mode
2. B.Overlay networking (VXLAN/Geneve)
3. C.Private VLAN (PVLAN)
4. D.External virtual switch

Answer + AI explanation with Pro

1. A.External virtual switch — a Hyper-V switch giving VMs and host access to the physical network
2. B.External virtual switch — A virtual network adapter presented to a VM (e.g. VMXNET3, virtio-net) that connects to a virtual switch port
3. C.External virtual switch — A vDS feature that allocates uplink bandwidth shares to traffic types (vMotion, vSAN, VM, management) to prevent any one from starving others
4. D.External virtual switch — Allocates distributed switch bandwidth to traffic types (vMotion, vSAN, VM) using shares, limits, and reservations.

Answer + AI explanation with Pro

1. A.a Hyper-V switch allowing VM-to-VM traffic only
2. B.Link-layer discovery protocols that map virtual switch uplinks to physical switch ports and VLANs.
3. C.Offloads splitting large TCP buffers into MTU-sized segments to the NIC, reducing host CPU usage.
4. D.Verifies VLAN, MTU, and teaming consistency between the distributed switch and physical switch ports.

Answer + AI explanation with Pro

1. A.Private VLAN (PVLAN)
2. B.TSO and LRO offload
3. C.LACP modes (active/passive)
4. D.Private virtual switch

Answer + AI explanation with Pro

1. A.Private virtual switch — vDS rules that allow, drop, or DSCP/CoS-tag packets at the port group level for security and QoS.
2. B.Private virtual switch — A virtual switch security setting that lets a vNIC see all traffic on the port group, needed for nested hypervisors and packet sniffers
3. C.Private virtual switch — Verifies VLAN, MTU, and teaming consistency between the distributed switch and physical switch ports.
4. D.Private virtual switch — a Hyper-V switch allowing VM-to-VM traffic only

Answer + AI explanation with Pro

1. A.Allocates distributed switch bandwidth to traffic types (vMotion, vSAN, VM) using shares, limits, and reservations.
2. B.The Data Plane Development Kit: userspace poll-mode drivers that bypass the kernel network stack for line-rate packet processing in NFV virtual switches
3. C.A virtual network adapter presented to a VM (e.g. VMXNET3, virtio-net) that connects to a virtual switch port
4. D.Policies (route based on originating port, source MAC, or physical NIC load) that distribute VM traffic across multiple uplinks for bandwidth and redundancy

Answer + AI explanation with Pro

1. A.Overlay networking (VXLAN/Geneve)
2. B.Jumbo frames (MTU 9000)
3. C.Virtual NIC (vNIC)
4. D.Port group

Answer + AI explanation with Pro

1. A.Virtual NIC (vNIC) — Exports flow records (src, dst, ports, bytes) from a vDS to a collector for traffic analysis.
2. B.Virtual NIC (vNIC) — A virtual network adapter presented to a VM (e.g. VMXNET3, virtio-net) that connects to a virtual switch port
3. C.Virtual NIC (vNIC) — Offloads splitting large TCP buffers into MTU-sized segments to the NIC, reducing host CPU usage.
4. D.Virtual NIC (vNIC) — Copies traffic from source ports to a destination for packet capture and intrusion detection.

Answer + AI explanation with Pro

1. A.A template on a virtual switch defining VLAN, security and teaming policy for the VMs connected to it
2. B.A vDS feature subdividing a VLAN into promiscuous, isolated and community secondary VLANs to restrict guest-to-guest traffic within a subnet
3. C.A virtual network adapter presented to a VM (e.g. VMXNET3, virtio-net) that connects to a virtual switch port
4. D.A hardware feature where one physical NIC exposes multiple virtual functions assignable directly to VMs, bypassing the virtual switch for low latency

Answer + AI explanation with Pro

1. A.Private VLAN (PVLAN)
2. B.Port mirroring (SPAN)
3. C.Overlay networking (VXLAN/Geneve)
4. D.MAC learning

Answer + AI explanation with Pro

1. A.Private VLAN (PVLAN) — A vDS feature subdividing a VLAN into promiscuous, isolated and community secondary VLANs to restrict guest-to-guest traffic within a subnet
2. B.Private VLAN (PVLAN) — The Data Plane Development Kit: userspace poll-mode drivers that bypass the kernel network stack for line-rate packet processing in NFV virtual switches
3. C.Private VLAN (PVLAN) — Copies traffic from source ports to a destination for packet capture and intrusion detection.
4. D.Private VLAN (PVLAN) — a per-host virtual switch

Answer + AI explanation with Pro

1. A.Policies (route based on originating port, source MAC, or physical NIC load) that distribute VM traffic across multiple uplinks for bandwidth and redundancy
2. B.Policies like route-by-port-ID, source-MAC-hash, or IP-hash (required for static EtherChannel) spread uplink traffic.
3. C.A template on a virtual switch defining VLAN, security and teaming policy for the VMs connected to it
4. D.Exports flow records (src, dst, ports, bytes) from a vDS to a collector for traffic analysis.

Answer + AI explanation with Pro

1. A.MAC learning
2. B.NetFlow
3. C.Overlay networking (VXLAN/Geneve)
4. D.Port group

Answer + AI explanation with Pro

1. A.Port group — a virtual switch managed centrally by vCenter across hosts
2. B.Port group — Copies traffic from source ports to a destination for packet capture and intrusion detection.
3. C.Port group — A template on a virtual switch defining VLAN, security and teaming policy for the VMs connected to it
4. D.Port group — Link-layer discovery protocols that map virtual switch uplinks to physical switch ports and VLANs.

Answer + AI explanation with Pro

1. A.Policies (route based on originating port, source MAC, or physical NIC load) that distribute VM traffic across multiple uplinks for bandwidth and redundancy
2. B.A template on a virtual switch defining VLAN, security and teaming policy for the VMs connected to it
3. C.A vDS capability that dynamically learns guest MAC addresses on a port, required to support nested ESXi and multiple MACs behind one vNIC
4. D.Policies like route-by-port-ID, source-MAC-hash, or IP-hash (required for static EtherChannel) spread uplink traffic.

Answer + AI explanation with Pro

1. A.NIC teaming load balancing
2. B.NetFlow
3. C.VST mode
4. D.TCP Segmentation Offload (TSO)

Answer + AI explanation with Pro

1. A.NIC teaming load balancing — a virtual switch managed centrally by vCenter across hosts
2. B.NIC teaming load balancing — Allocates distributed switch bandwidth to traffic types (vMotion, vSAN, VM) using shares, limits, and reservations.
3. C.NIC teaming load balancing — A vDS feature subdividing a VLAN into promiscuous, isolated and community secondary VLANs to restrict guest-to-guest traffic within a subnet
4. D.NIC teaming load balancing — Policies (route based on originating port, source MAC, or physical NIC load) that distribute VM traffic across multiple uplinks for bandwidth and redundancy

Answer + AI explanation with Pro