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Highlighted
Beginner

Cisco 2800 IRB or VLAN or Both?

Good day and thank you for taking the time to read this.  My current setup is a Cisco 2811 router with v15.1 IOS, dhcp WAN through external cable modem.  I am able to get more dhcp addresses on my subscription.  I have been reading the IRB documents to see if there is a way to have the router grab one address and do what it is currently doing, and then have a bridge to another router or Linux NIC to grab another WAN dhcp address for other purposes.  I can't seem to get the bridging to work.  Here are a few pieces of the config WITHOUT any IRB or Vlans so you can get an idea of the topology here.  Thanks!

Router#show run
Building configuration...


Current configuration : 3799 bytes
!
! Last configuration change at 13:06:32 PDT Sat Mar 22 2014
version 15.1
service timestamps debug datetime msec
service timestamps log datetime msec
service password-encryption
!
hostname Router
!
boot-start-marker
boot-end-marker
!
!

!
no aaa new-model
!
clock timezone PST -8 0
clock summer-time PDT recurring
!
crypto pki token default removal timeout 0
!
!
dot11 syslog
ip source-route
!
!
ip cef
!
no ip dhcp use vrf connected
ip dhcp binding cleanup interval 10

!
ip dhcp pool HOME
 network 172.16.0.0 255.255.252.0
 default-router 172.16.1.1
 dns-server 172.16.1.100
 option 42 ip 172.16.1.1
 option 66 ip 172.16.1.105
!

!
!

!
ipv6 unicast-routing
ipv6 cef
!
multilink bundle-name authenticated
!
!
!
!
!
!
!
voice service voip
 sip
!
!
!
!
!
voice-card 0
!
!
!
license udi pid CISCO2811 sn
!
redundancy
!
!
!
!
!
!
!
!
!
!
interface FastEthernet0/0

 ip ddns update no-ip
 ip address dhcp
 ip access-group 123 in
 ip accounting output-packets
 ip nat outside
 ip virtual-reassembly in
 duplex auto
 speed auto
 ipv6 address dhcp
 ipv6 enable
 ipv6 nd autoconfig default-route
 ipv6 dhcp client pd PREFIX_1
!
interface FastEthernet0/1
 ip address 172.16.1.1 255.255.252.0
 ip nat inside
 ip virtual-reassembly in
 duplex auto
 speed auto
 ipv6 address PREFIX_1 ::1/64
 ipv6 enable
 ipv6 nd other-config-flag
!
interface FastEthernet1/0
 no ip address
 shutdown
 duplex auto
 speed auto
!
ip forward-protocol nd
no ip http server
no ip http secure-server
!
!
ip nat inside source list 1 interface FastEthernet0/0 overload

ip route 0.0.0.0 0.0.0.0 dhcp
!
access-list 1 permit 172.16.0.0 0.0.255.255
access-list 123 permit tcp 0.0.0.0 255.255.252.0 any eq telnet
access-list 123 deny   tcp any any eq telnet
access-list 123 permit ip any any
access-list 144 permit ipinip any any
!
!
!
!
!
!
control-plane
!
!
!
!
mgcp profile default
!
!

!
!
sip-ua
 sip-server ipv4:172.16.1.105:5060
!
!
!
gatekeeper
 shutdown
!
!
!

!
scheduler allocate 20000 1000

end

 

3 REPLIES 3
Highlighted

Hello, Phil.

As I understood your question you want to get more than 1 public IP-address from provider. If so, then why do you need them if you run NAT?

If you want port mapping, then it could be configured with single IP-address.

Highlighted

Two reasons.  1) I cannot get enough public IP addresses to assign to all of my interfaces.  2) I have a situation where I need to serve as a gateway to a public IP address block (44-net, if you are familiar with that).  In order to do that with a single public IP, I would have to employ a type of double NAT, and that doesn't work so well with the frequent routing updates on the 44 network.  The second public IP I want to route directly to a NIC on my Linux box to handle the 44 stuff.

 

Thanks!
 

Highlighted
Beginner

Actually, forget it - that wont work.  It turns out I do not get multiple public IPs from my ISP.

 

I think I will need to set up a vlan with ipinip encap.