In traditional networking, a static IP refers to a fixed public IP address manually assigned to a device that doesn't change over time. AWS's Elastic IP (EIP) is a cloud-specific implementation with additional features beyond traditional static IPs.

While both provide persistent addresses, key distinctions include:

• Association Flexibility: EIPs can be rapidly remapped between EC2 instances or NAT gateways
• Billing Model: AWS charges for unused EIPs ($0.005/hr) to encourage efficient allocation
• Cloud Integration: EIPs work with AWS-specific features like VPCs and Route 53

Here's when to use each:

# Assigning Elastic IP via AWS CLI
aws ec2 allocate-address --domain vpc
aws ec2 associate-address --instance-id i-1234567890abcdef0 --public-ip 203.0.113.0

For traditional static IPs in on-prem setups:

# Linux static IP configuration
sudo nano /etc/netplan/01-netcfg.yaml

network:
  version: 2
  ethernets:
    eth0:
      dhcp4: no
      addresses: [192.168.1.100/24]
      gateway4: 192.168.1.1
      nameservers:
        addresses: [8.8.8.8,8.8.4.4]

EIPs provide cloud-native advantages:

• Automatic DNS hostname mapping
• Integration with CloudFormation templates
• Support for BYOIP (Bring Your Own IP) in enterprise plans

When working with EIPs:

// CloudFormation EIP resource example
Resources:
  MyEIP:
    Type: AWS::EC2::EIP
    Properties:
      Domain: vpc
      InstanceId: !Ref MyEC2Instance

Remember that AWS accounts initially limit you to 5 EIPs per region, though this can be increased via support tickets.

Avoid these mistakes:

• Forgetting to release unused EIPs (incurring charges)
• Assuming EIPs provide HA (they don't - use DNS failover instead)
• Mixing EIP assignments between EC2-Classic and VPC environments

While both Elastic IP (EIP) and traditional static IP addresses provide persistent public IP assignments, AWS's implementation carries crucial architectural differences. Unlike conventional static IPs tied to physical hardware, EIPs are dynamic cloud resources managed through AWS's control plane.

• Cloud-native allocation: EIPs exist independently from EC2 instances
• Reassignment capability: Can be remapped between instances in seconds
• Regional scope: Bound to an AWS region (unlike global static IPs)
• Association model: Uses one-to-one mapping with network interfaces

Here's how to manage EIPs using AWS CLI:

# Allocate new EIP
aws ec2 allocate-address --domain vpc

# Associate with instance
aws ec2 associate-address \
    --instance-id i-1234567890abcdef0 \
    --allocation-id eipalloc-12345678

# Disassociate and release
aws ec2 disassociate-address --association-id eipassoc-12345678
aws ec2 release-address --allocation-id eipalloc-12345678

AWS charges for EIPs only when:

• The EIP is not associated with a running instance
• The associated instance is stopped (not terminated)
• You exceed your account's free EIP quota (5 per region)

EIPs have several unique constraints:

• Cannot transfer between regions directly
• Behind-the-scenes NAT occurs (unlike true static IPs)
• DNS propagation delays can occur during reassignment
• Requires VPC configuration (classic EC2 has different behavior)

Traditional static IPs may be preferable for:

• On-premises infrastructure integration
• Legacy systems requiring hardware-bound addressing
• Specialized network appliances with static ARP requirements