Question for People with advanced cisco knowledge

nice343 · August 2007

I have two public Ip address subnets.

Public address A and B

I would like to provide internet connections for Public address A, how should I go about it?

should I ask the ISP so we can deploy some sort of a routing protocol? Because from my understanding, that is the only way Public address A can access the internet.

I don not need to perform a NAT because the addesses are already public ones not private.

Any help will be deeply appreciated.

ilcram19 · August 2007

i dont undestand but if u dont wanna use nat...create and static route or and ip route to the network B, and use acl's to block access

but i still sujest to user NAT overload (PAT) create the corect access list for the inbound and outbound interface abd you'll be all set

ilcram19 · August 2007

hold up wut!!!...

I don not need to perform a NAT because the addesses are already public ones not private

so why are you using the router then, you could use if u using windows XP the windows firewall to protect your computer....r u trying to use the router as a hub?...u still gonna have to asign address to the inbound and outbound interfaces if the router to let in and out traffic.
just take the public ip assignate it to the router outbound interface, create private subnet then create a nat

nice343 · August 2007

ilcram19 wrote:

hold up wut!!!...

I don not need to perform a NAT because the addesses are already public ones not private

so why are you using the router then, you could use if u using windows XP the windows firewall to protect your computer....r u trying to use the router as a hub?...u still gonna have to asign address to the inbound and outbound interfaces if the router to let in and out traffic.
just take the public ip assignate it to the router outbound interface, create private subnet then create a nat

I have assigned Ip addresses to both inbound and out bound interfaces. Both interfaces are on two different subnets. which are public addresses. I was just wondering how the hosts can connect to the internet with two seperate addresses on two interfaces which are both public IPs

blargoe · August 2007

Make the default route on the router be the route to the Internet. Then make the default gateway of the host be the interface of the router that is connected to the host's subnet.

sprkymrk · August 2007

Are all your computers (behind the router) using public ip's also? They only need to be aware of interface A on the router. You set that as their default gateway and you're done. The router will do it's job automatically because it knows which networks are attached to each interface. If you are using a single public ip on interface A and one on B, but you'tre computers are not using public IP's then there is no point in assigning a public IP to the inside interface.

If, on the other hand, you're actually asking "How do I set up and configure my router?" then that's a longer story. Do you know how to assign IP addresses to the interfaces?

Can you provide some more details on exactly what you are trying to do?

nice343 · August 2007

sprkymrk wrote:

Are all your computers (behind the router) using public ip's also? They only need to be aware of interface A on the router. You set that as their default gateway and you're done. The router will do it's job automatically because it knows which networks are attached to each interface. If you are using a single public ip on interface A and one on B, but you'tre computers are not using public IP's then there is no point in assigning a public IP to the inside interface.

If, on the other hand, you're actually asking "How do I set up and configure my router?" then that's a longer story. Do you know how to assign IP addresses to the interfaces?

Can you provide some more details on exactly what you are trying to do?

you may have answered my question but I am not in the office right now. I will go there next week and see if that is going to work

ilcram19 · August 2007

u can use a static route pointing to the out side network....or u can use a dymanic routing protocol and add the network to the routing table so the can forward traffic, but that would be only the router interfaces...a nat is always implemented in this cases u can use bot the public address to have a nat pool, did u pay for those address? anyways
what kind of router do u have?

TechJunky · September 2007

Just tie both public addresses to the inbound/outbound interface, use NAT and statically assign routes with ACL's that allow whatever ports you want forwarded to whatever internal IP address...

I would hardly call this an advanced question either.

Good luck.

networker050184 · September 2007

Do you have two public subnets or ip addresses? If you have two subnets this should be very simple and you wouldn't even need the NAT. Even if you need to use NAT it is a pretty simple configuration. Just use a static route sending all non local traffic out the interface connecting to the net.

dtlokee · September 2007

This configuration could be far more complex than you may think. If you have an address rnge which is not part of your provider's address block theymay be unwilling to advertise it to the Internet for you (remember routing is a 2 way process, you need a path to the destination, and the destination needs a path back to your network). Additionally if your address allocation is smaller than a /19 it may be impossible to advertise becaus some ISPs will only accept a /19 or shorter mask. You will need to advertise your address range to the ISP, typically requiring BGP and a router that can handle an entire Internet routing table.

More information about what you're doing would be helpful, but you may be in the same boat as some of my cstomers who have an older class C allocation that cannot be advertised so they end up doing NAT.

Question for People with advanced cisco knowledge

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