2 public IP address

[navneet-k1]

Why do we need 2 public ip address. What is the use case how it is different from having 1 public ip address. What is the benefit? How do I know which one I should take (1 public ip connection or 2 public ip connection for my small office)

[MHM Cisco World]

If you have server behind router then it better to have two public IP 
one IP for all client to access internet 
other IP use by client outsider in internet to access server.

if you have mnay client and need to access internet then you can use pool of public ip to prever NAT exhausted 

[navneet-k1]

Thank you for the response. If I have only 1 public ip then server behind can't be accessed remotely using VPN?

[MHM Cisco World]

it Can but it recommend to use separate public IP.   

[navneet-k1]

What if I have 2 servers behind the router?

[navneet-k1]

I have 2 servers behind the router & many other endpoints. Please suggest how many public IP is good for this config/architecture.

[MHM Cisco World]

Server is same ? meaning server use same UDP TCP port ?

[navneet-k1]

So you mean If there is a server which needs direct access over the internet then it is better to have 2 public IP. One for user connectivity to the internet & other one is for Server. The primary reason for this security measure is that in most cases corporate networks are behind firewalls and proxies. Having two IP addresses will allow you to route traffic from the proxy or firewall directly to the server and vice versa.

[MHM Cisco World]

Correct, it recommend 

[Joseph W. Doherty]

Consider this analogy.

Assume mailing addresses cannot have recipient names but different addresses can be delivered to the same location.  Do you need more than one address?

If there's only you, likely one address is fine.  If there is someone else at the same address, likely you will want an additional address.

Also, for the above, if you send mail to someone else you can use different color envelopes and replies will always be same color.  But, others sending to you (not replies) use colors not meaningful to you.

For mail you send (not replies) you can use color coding to avoid the need for using multiple addresses but not so for the converse.

[katrin1701]

Would the 2 ip addresses be from the same ISP? If not you'd have redundancy.