How to get my Cisco 877w working with multiple dynamic IP addresses through DHCP on the WAN (ADSL)

[pasi.pukema]

Hi

I haw a cico 877w and like to have configuration help for it

My ADSL operator will give 5 public dynamic IP addresses by DHCP but I can’t get the configuration to manage that. My knowledge of ATM (ADSL) is limited and in internet there are only sample configurations for multiple static IP addresses not multiple dynamic IP addresses from wan (ADSL) side DHCP

Any idea for configuration? or some information how to use ATM sub interfaces and BVI

Thanks.

[paolo bevilacqua]

Can you post a link with the details of this service 5 dynamic public addresses on the same circuit ?

Because it technically challenging if not impossible, and I never heard on any ISP that does that.

[pasi.pukema]

I now have Televell (TW-EA501) ADSL router installed and I can get dynamic Public IP address for firewall (PIX501) and phone ”adapter” that I connect to the ADSL router. (different VLANs)

The Router is in Bridget mode and I have 2 VLAN at the Switch interfaces. If I make more VLANs I could get more public IP addresses.

I don’t know how it’s done but I like to have same kind of configuration in my Cisco 877W router.

The operator is teliasonera www.sonera.fi and its operates in Finland.

In the "palvelukuvaus.pdf" (service samting) it sed you can connect 5 computers.

Soneran operaattoriasetukset
Yhteysmuoto
Bridged   (eli siltaava)
RFC 2684 / RFC 1483
ATM-parametrit
VPI	0
VCI	33
Modulointiasetukset
Yli 8 Mbit/s liittymä	ADSL2+        Annex A (ADSL-liittymät) ADSL2+        Annex M (Extra, ADSL-tekniikalla toteutettu)
8 Mbit/s tai alle	ITU-T        G.dmt ANSI        T1.413 issue 2

[paolo bevilacqua]

Using the cisco, you can also give the addresses to external PC, however they will be in the same VLAN.

I don't know wither how they are getting the addresses to diffrent vlans using ISP modem. Do they use dot1q interface, or what ?

You can also have the cisco get an address, and do NAT for more computers on a different VLAN.

So the point can be, how doyou want to use these addresses ?

[pasi.pukema]

I have trait to ask for configuration of telewell from ISP but noting…

I just need 3 public addresses, Firewall, NET phone and one for reserve for some server (FTP…)

I maid do the firewall on routers IOS firewall and take the pix501 out of service, its old.

I was thinking configuration like: one port (port group BVI) from routers switch is behind IOS firewall and NAT (PAT) and 2 ports (BVI2) public dynamic IP addresses from ISP DHCP.

I remembered wrong those public addresses are in same VLAN.

In first picture there is WAN interface and I think that the upper “main wan connection” maid be ATM interface and the “wan bridge connection” is ATM 0.1 sub interface. I can create those more…

There are also build-in configurations for use.

In second picture there is LAN switch configuration and VLANs. I have used the bridge public IP address interface in ports 3 and 4

My problem is that i don’t know how to configure ATM and BVI interfaces, where to but what…

[paolo bevilacqua]

bridge irb

bridge 1 route ip

bridge 1 protocol ieee

You can only have one BVI interface per bridge group, in other words the rotuer can take only 1 address from ISP.

[pasi.pukema]

So BVI is not the way to go?

Is there any other solutions? Or is the one IP from ISP the only way?

[paolo bevilacqua]

As mentioned above.

Router can use only one address from ISP, the others can be given directly to other devices.

[pasi.pukema]

Yes that would be the configuration that I could use, if the IP address off Router could be use of PAT and access list (firewall /LAN) and other devices connected to routers switch ports would get public IP addresses.

So how I can make configuration like that??? Can you give me some sample configuration to go an??

btw, thank you for jour interest and help…

[paolo bevilacqua · Accepted solution]

That is the normal BVI configuation for rfc bridged adsl that you find in all the examples

In addition, you put place another VLAN in the same bridge-group, containing the devices that will receive public address.

Thank you for the nice rating and good luck!.