When working with virtual machines, selecting the right NIC type impacts both performance and compatibility. Common types include:

• E1000: Intel emulated adapter (best for compatibility)
• VMXNET3: VMware paravirtualized adapter (optimized for performance)
• VMXNET2: Older VMware paravirtualized adapter
• VirtIO: Common in KVM environments

While NIC selection typically occurs during VM creation, real-world scenarios often require changes:

• Performance tuning after workload analysis
• Migrating VMs between hypervisors
• Troubleshooting compatibility issues
• Preparing for new network features

Here's how to modify NIC types using vSphere (PowerCLI examples included):

Method 1: Using vSphere Web Client

1. Right-click VM → Edit Settings
2. Expand the network adapter section
3. From dropdown: Select new adapter type
4. Save changes

Method 2: PowerCLI Script

# Connect to vCenter
Connect-VIServer -Server vcenter.example.com

# Get VM object
$vm = Get-VM -Name "MyVM"

# Get network adapter (assuming first NIC)
$adapter = $vm | Get-NetworkAdapter

# Change to VMXNET3
Set-NetworkAdapter -NetworkAdapter $adapter -Type "Vmxnet3" -Confirm:$false

# Verify change
Get-NetworkAdapter -VM $vm | Select Name, Type

Method 3: Using OVF Tool for Bulk Changes

ovftool \
--X:injectOvfEnv \
--powerOn \
--acceptAllEulas \
--noSSLVerify \
--allowExtraConfig \
--extraConfig:ethernet0.virtualDev=vmxnet3 \
vi://user:password@vcenter.example.com/VM/path

Guest OS Preparation

Before changing to VMXNET3:

1. Install VMware Tools (contains required drivers)
2. For Linux: Ensure vmxnet3 kernel module is available

Network Impact

• MAC address changes may occur
• IP configuration might reset
• Firewall rules may need updating

Best Practice Workflow

1. Take VM snapshot
2. Document current network config (ipconfig/ifconfig)
3. Change NIC type
4. Verify driver installation
5. Test connectivity
6. Remove snapshot after verification

Missing VMXNET3 Option?

Possible causes:

• VM hardware version too old (upgrade to v13+)
• Guest OS not supported in compatibility list
• VMware Tools not installed

Network Connectivity Loss

Recovery steps:

1. Check dmesg or system logs for driver errors
2. Verify NIC appears in lspci (Linux) or Device Manager (Windows)
3. Compare MAC addresses pre/post change

Metric	E1000	VMXNET3
Max Throughput	1Gbps	10Gbps+
CPU Utilization	High	Low
Jumbo Frames	No	Yes (9000+ MTU)

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When provisioning virtual machines, administrators typically select between different virtual NIC types like:

• E1000: Intel emulated adapter (best for compatibility)
• VMXNET3: VMware paravirtualized adapter (better performance)
• virtio: Common in KVM environments

While NIC type selection occurs during VM creation, you can modify it post-deployment through these methods:

1. Right-click VM → Edit Settings
2. Expand network adapter section
3. Change "Adapter Type" dropdown
4. Click OK to apply changes

For bulk operations, use this PowerShell snippet:

Get-VM "TestVM" | Get-NetworkAdapter | 
Set-NetworkAdapter -Type Vmxnet3 -Confirm:$false

When changing NIC types:

• Guest OS may require driver installation (especially for VMXNET3)
• IP configuration might reset after adapter change
• Some cloud platforms restrict NIC type modifications