Public IP blocks on cisco router

Posted on 2012-03-28
Last Modified: 2012-06-27
I have a block of 8 IP's from my ISP. I need another block of 8. How on a cisco router do I add the 8 additional IP's to the same Interface?
Question by:sicm
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Expert Comment

by:Don Johnston
ID: 37779676
Well, if you have a block of 8 IP addresses, you don't necessarily have those 8 IP addresses assigned to the router.  

Most likely, you have NAT statements that translate inside addresses to those addresses in the block.

You would have to provide additional information. Posting a sanitized router config would help.

Author Comment

ID: 37779934
Thanks for the response.

Basically what I have is a block of 8 IP's from my ISP all in a subnet. One of them is assigned to the Router interface and one is assigned to the outside face of my firewall. The rest are natted to internal applications. I need more. So my question is if I buy an additional subnet from my ISP with 16 public IP's in a different subnet how could I add them to the router? Do i have to rip and replace the subnet that currently exists or can you somehow add both blocks of IP's to the same interface?

Hope that helps clear up the question.
LVL 50

Expert Comment

by:Don Johnston
ID: 37780130
You'll simply add NAT statements for the additional addresses.

Accepted Solution

klassa earned 500 total points
ID: 37780437
Maybe you can do secondary interface, like this.

router(config-if)#ip address
router(config-if)#ip address secondary

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