CCP Adding Additional IP Alias to WAN Interface (CPP / BT Broadband)

[andrew.vint]

Hi,

This may be a simple question but as a newbie who is finding his way around Cisco Configuration Professional (CCP) but where do i put in additional public IP addresses as issued by my ISP.

I have BT Business Boradband here in the UK and i am in the process of configuring a Cisco 877 to replace the standard 2Wire router and i have managed to get online and configure the Zone Based Firewall and all si good.

That is apart from the fact i have no idea where to add in the 5 static IP addresses i have.

Any help greatfully recieved.

Andrew

[chaitram]

Hi Andrew,

  If you are trying to configure secondary IP addresses on the interface, Cisco Configuration Professional does not support it yet. You could use the following CLI to configure

Router#conf t
Enter configuration commands, one per line.  End with CNTL/Z.
Router(config)#interface
Router(config-if)#ip address

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

[andrew.vint]

Hi ...

Thanks for the info ... i now have one small issue that i hope you can help me with.

The primary connection i have on my broadband is a dynamically assigned address that changes quite often. I have five secondary IP addresses assigned to the interface which are accepting inbound connections no problem.

However when i go to check what my public ip address is it is reported as the dynamic one (this causes major issues especially with email).

How do i tell the router to present itself using one of ths static IP addresses instead of the dynamic one while mainting the connection process.

Thanks

[Richard Burts · Accepted solution]

Andrew

I wonder if secondary addresses are really the best way to use the additional addresses that you have. In the situation where you have a router connected to the Internet and learning an address dynamically and the provider has given you a block of public addresses, it is commonly done to use the public addresses for address translation. In doing this your Email server would have a private address inside your network, and the router would be configured with a static address translation such that one of the static public addresses would translate to the private inside address of the mail server. In doing this the mail server would always appear on the same public address no matter what address the router has learned on its interface.

HTH

Rick

[andrew.vint]

Rick,

I never thought of that, and in reflection that is a perfect scenario for servers but i also have a number of SIP phones and a hosted telphony provider that really dont like dynamic addressing.

If i put them in a fixed range could i do the same for the SIP phones and assign a static ip adress to that range ?

Please excuse my ignorance but this is a learning curve for me.

Thanks