CCNA6-4

350 Chapter 6  IP Routing
R2(config)#enable secret todd
R2(config)#int s0/2/0
R2(config-if)#ip address 10.1.4.2 255.255.255.0
R2(config-if)#description Connection to Corp ISR Router
R2(config-if)#no shut
R2(config-if)#int f0/0
R2(config-if)#ip address 10.1.9.1 255.255.255.0
R2(config-if)#description Connection to HostC
R2(config-if)#no shut
R2(config-if)#int dot11radio 0/3/0
R2(config-if)#ip address 10.1.8.1 255.255.255.0
R2(config-if)#description Admin WLAN
R2(config-if)#ssid ADMIN
R2(config-if-ssid)#guest-mode
R2(config-if-ssid)#authentication open
R2(config-if-ssid)#infrastructure-ssid
R2(config-if-ssid)#no shut
R2(config-if)#line con 0
R2(config-line)#password console
R2(config-line)#login
R2(config-line)#logging sync
R2(config-line)#exec-timeout 0 0
R2(config-line)#line aux 0
R2(config-line)#password aux
R2(config-line)#login
R2(config-line)#exit
R2(config)#line vty 0 ?
<1-807> Last Line number

R2(config)#line vty 0 807
R2(config-line)#password telnet
R2(config-line)#login
R2(config-line)#exit
R2(config)#banner motd # This is my R2 ISR Router #
R2(config)#no ip domain-lookup
R2(config)#^Z
R2#copy run start
Destination filename [startup-config]?[enter]
Building configuration...
[OK]
R2#
The IP Routing Process 351
Nice—everything was pretty straightforward except for that wireless interface. It’s true, the
wireless interface is really just another interface on a router, and it looks just like that in the routing
table as well. But, in order to bring up the wireless interface, more configurations are needed than
for a simple FastEthernet interface. So check out the following output, and then I’ll tell you about
the special configuration needs for this wireless interface:
R3(config-if)#int dot11radio0/3/0
R2(config-if)#ip address 10.1.8.1 255.255.255.0
R3(config-if)#description Connection to Corp ISR Router
R3(config-if)#no shut
R3(config-if)#ssid ADMIN
R3(config-if-ssid)#guest-mode
R3(config-if-ssid)#authentication open
R3(config-if-ssid)#infrastructure-ssid
R2(config-if-ssid)#no shut
So, what we see here is that everything is pretty commonplace until we get to the SSID configuration.
This is the Service Set Identifier that creates a wireless network that hosts can connect to.
Unlike access points, the interface on the R2 router is actually a routed interface, which is the reason
why the IP address is placed under the physical interface—typically the IP address would be
placed under the management VLAN or Bridge-Group Virtual Interface (BVI).
That guest-mode line means that the interface will broadcast the SSID so wireless hosts
will understand that they can connect to this interface. Authentication open means just
that…no authentication. (Even so, you still have to type that command in at minimum to
make the wireless interface work.) Last, the infrastructure-ssid indicates that this interface
can be used to communicate to other access points, or other devices on the infrastructure—
to the actual wired network itself.
But wait, we’re not done yet—we still need to configure the DHCP pool for the wireless clients:
R2#config t
R2(config)#ip dhcp pool Admin
R2(dhcp-config)#network 10.1.8.0 255.255.255.0
R2(dhcp-config)#default-router 10.1.8.1
R2(dhcp-config)#exit
R2(config)#ip dhcp excluded-address 10.1.8.1
R2(config)#
Creating DHCP pools on a router is actually a pretty simple process. To do so, you just
create the pool name, add the network/subnet and the default gateway, and exclude any
addresses you don’t want handed out (like the default gateway address). And you’d usually
add a DNS server as well.
The output of the following show ip route command displays the directly connected networks
of 10.1.9.0, 8.0, and 4.0, as you can see here:
R2#sh ip route
10.0.0.0/24 is subnetted, 3 subnets
352 Chapter 6  IP Routing
C 10.1.9.0 is directly connected, FastEthernet0/0
C 10.1.8.0 is directly connected, Dot11Radio0/3/0
C 10.1.4.0 is directly connected, Serial0/2/0
R2#
The Corp, R1, and R2 routers now have all their links up. But we still need to configure R3
(the 871W router) and the 1241 AP.
Wireless networks will be discussed in detail in Chapter 12, “Cisco’s Wireless
Technologies.”
R3 Configuration
Just as I said, I’m going to use the SDM for the R3 router. My first step is to set an IP address
on the F0/0 interface. I used a crossover cable to connect my PC directly to the f0/0 port.
Now since I want to set up the router with security, I’ve got to configure the router back
to the factory defaults. I can do this via the CLI just as I showed you back in Chapter 4, but
it’s actually a whole lot easier to do this using SDM!
Using HTTP, I was able to access the R3 router, go to the Configure page, and choose Additional
Tasks. Then, I just clicked on Configuration Management and Reset to Factory Default.
I clicked the Reset Router button in the bottom-right corner and then configured my PC
using the directions shown on the screen in the above screen shot.
The IP Routing Process 353
Again, using HTTPS, I connected back to SDM using the 10.10.10.1 address that was provided
in the directions. SDM had me log in twice with the username cisco as well as a password of cisco.
I then had to accept the certificate from the router, and I’m good to go with a secure connection.
The first thing the router had me do after SDM was loaded was change the username
and password.
Then I needed to log in again using my new name and password.
After that, I chose Configure and then Interfaces and Connections, which is in the upperleft
corner, under Home. Clicking the Serial (PPP, HDLC or Frame Relay) button got me to
where I could choose Create New Connection.
354 Chapter 6  IP Routing
The Create New Connection button took me to the WAN Wizard.
I was then able to choose my interface; then I clicked Next.
The IP Routing Process 355
I then chose High-Level Data Link Control and clicked Next. (I’ll get into HDLC in
Chapter 14.)
I was then able to add my IP address and mask.
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IP Unnumbered is truly an interesting configuration because it lets you set up a network
connection without using an IP address. Instead, you “borrow” an IP address from another
active interface. This comes in pretty handy if you happen to be a bit short on subnets!
Anyway, the next screen asked if I wanted to set up static routing and NAT. Again, this is
something I’ll get into more later on, so we’re not going to configure it just yet.
Moving on, I clicked Next and received a summary of my serial 0/0/1 configuration.