It can be useful to have multiple IP addresses to your instance in VPC to do the following
- Host multiple websites on a single server by using multiple SSL Certificates on a single server and associating each server with a specific ip address.
- Operate network appliances, such as firewalls and load balancers that have multiple private ip addresses for each network interface
- Redirect internal traffic to a standby inatance in case your instance fails by re-assigning the secondary private ip address to the standby instance
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