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Chapter 7      Router Feature Configuration
Configuring IP EIGRP
For complete information on the IP EIGRP commands, refer to the 
Cisco IOS Release 12.0 documentation set. For more general information on 
EIGRP concepts, see Chapter 1, “Concepts.”
Configuration Example
The following configuration shows EIGRP routing protocol enabled in IP 
networks 10.0.0.0 and 172.17.0.0. The EIGRP autonomous system number is 
assigned as 100.
You do not need to enter the commands marked “default.” These commands 
appear automatically in the configuration file that is generated when you use the 
show running-config command.
!
router eigrp 100
network 10.0.0.0
network 172.17.0.0
!
Verifying Your Configuration
To verify that you have properly configured IP EIGRP, enter the show ip route 
command and look for EIGRP routes signified by “D.” You should see a 
verification output like the following example.
router#sh ip route
Codes:C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - 
BGP
       D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area 
       N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
       E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP
       i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, ia - IS-IS 
inter area
       * - candidate default, U - per-user static route, o - ODR
       P - periodic downloaded static route
Gateway of last resort is not set
2.0.0.0/24 is subnetted, 1 subnets
C  2.2.2.0 is directly connected, Ethernet0/0
D    3.0.0.0/8 [90/409600] via 2.2.2.1, 00:00:02, Ethernet0/0 
						

							 
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Configuring Addressing Parameters
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Configuring Addressing Parameters
This section describes how to configure addressing using Network Address 
Translation (NAT) and Easy IP Phase 1 and 2.
Configuring NAT 
You can configure NAT for either static or dynamic address translations.
Follow the steps below to configure static or dynamic inside source translation, 
beginning in global configuration mode.
Command Task
Step 1ip nat pool name start-ip end-ip {netmask 
netmask | prefix-length prefix-length}Create pool of global IP addresses for NAT. 
Step 2access-list access-list-number permit source 
[source-wildcard]Define a standard access list permitting 
addresses that need translation.
Step 3ip nat inside source list access-list-number 
pool nameEnable dynamic translation of addresses 
permitted by access list to one of addresses 
specified in pool.
Step 4ip nat inside source static local-ip global-ip 
number extendableEnable static translation of specified inside 
local address to globally unique IP address. 
This command is optional.
Step 5interface ethernet 0Enter configuration mode for the Ethernet 
interface.
Step 6ip nat insideEstablish the Ethernet interface as the inside 
interface.
Step 7exitExit configuration mode for the Ethernet 
interface.
Step 8interface atm 0Enter configuration mode for the ATM 
interface.
Step 9dsl equipment-type {co | cpe} Configure the DSL equipment type, if 
applicable. 
						

							 
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NoteIf you want to use NAT with a virtual template interface, you must configure a 
loopback interface.
For complete information on the NAT commands, refer to the 
Cisco IOS Release 12.0 documentation set. For general information on NAT 
concepts, see Chapter 1, “Concepts.”
Configuration Example
The following configuration shows NAT configured for the Ethernet and ATM 
interfaces.
The Ethernet 0 interface has an IP address of 192.168.1.1 with a subnet mask of 
255.255.255.0. NAT is configured for inside, which means that the interface is 
connected to the inside network that is subject to NAT translation.
The ATM 0 interface has an IP address of 200.200.100.1 and a subnet mask of 
255.255.255.0. NAT is configured for outside, which means that the interface is 
connected to an outside network, such as the Internet.
You do not need to enter the commands marked “default.” These commands 
appear automatically in the configuration file that is generated when you use the 
show running-config command.
!
interface Ethernet0
ip address 192.168.1.1 255.255.255.0
no ip directed-broadcast (default)
Step 10dsl linerate {number | auto} Specify the G.SHDSL line rate, if applicable. 
The range of valid numbers is between 72 and 
2312.
Step 11dsl operating-mode gshdsl symmetric 
annex annexSet the G.SHDSL operating mode, if 
applicable, and select the G.991.2 annex.
Step 12ip nat outsideEstablish the ATM interface as the outside 
interface.
Step 13exitExit configuration mode for the ATM 
interface. Command Task 
						

							 
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!
interface ATM0
ip address 200.200.100.1 255.255.255.0
no ip directed-broadcast (default)
ip nat outside
no atm ilmi-keepalive (default)
pvc 8/35 
encapsulation aal5snap
!
ip route 0.0.0.0.0.0.0.0 200.200.100.254
!
ip nat pool test 200.200.100.1 200.200.100.1 netmask 255.255.255.0
ip nat inside source list 101 pool test overload
ip classless (default)
!
Verifying Your Configuration
To verify that you have properly configured NAT, enter the show ip nat statistics 
command. You should see a verification output like the example shown below.
router#sh ip nat statistics 
Total active translations:45 (10 static, 35 dynamic; 45 extended)
Outside interfaces:
  ATM0
Inside interfaces:
  Ethernet0
Hits:34897598  Misses:44367
Expired translations:119305
Dynamic mappings:
-- Inside Source
access-list 1 pool homenet refcount 14
pool homenet:netmask 255.255.255.0
        start 200.200.100.1 end 200.200.100.1
        type generic, total addresses 1, allocated 1 (100%), misses 
Configuring Easy IP (Phase 1)
This section explains how to configure Easy IP (Phase 1). Easy IP Phase 1 
includes NAT overload and PPP/Internet Protocol Control Protocol (IPCP). NAT 
overload means that you can use one registered IP address for the interface and 
use it to access the Internet from all devices in the network.  
						

							 
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Chapter 7      Router Feature Configuration
Configuring Addressing Parameters
With PPP/IPCP, Cisco 800 series routers automatically negotiate a globally 
unique (registered or public) IP address for the interface from the ISP route.
Follow the steps below to configure Easy IP (Phase 1), beginning in global 
configuration mode.
Command Task
Step 1access-list access-list-number permit source 
[source-wildcard] Define a standard access list that permits 
nonregistered IP addresses of hosts.
Step 2ip nat inside source list access-list-number 
interface interface overloadSet up translation of addresses identified by 
the access list defined in Step 1.
Step 3interface ethernet 0Enter configuration mode for the Ethernet 
interface.
Step 4ip nat insideEstablish the Ethernet interface as the inside 
interface for NAT.
Step 5no shutdownEnable the Ethernet interface and the 
configuration changes just made to it.
Step 6exitExit configuration mode for the Ethernet 
interface.
Step 7interface dialer Enter configuration mode for the dialer 
interface. 
Step 8ip address negotiatedAssign a negotiated IP address to the dialer 
interface.
Step 9ip nat outsideEstablish the dialer interface as the outside 
interface for NAT.
Step 10dialer pool numberSpecify which dialer pool number you are 
using.
Step 11exitExit the dialer interface.
Step 12interface ATM 0Enter configuration mode for the ATM 
interface.
Step 13dsl equipment-type {co | cpe} Configure the DSL equipment type, if 
applicable.
Step 14dsl linerate {number | auto} Specify the G.SHDSL line rate, if applicable. 
The range of valid numbers is between 72 and 
2312. 
						

							 
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For complete information on the Easy IP commands, refer to the Cisco IOS 
Release 12.0 documentation set. For general information on Easy IP (Phase 1) 
concepts, see Chapter 1, “Concepts.” 
Configuring Easy IP (Phase 2) 
This section explains how to configure a Cisco 800 series router as a DHCP 
server.
The Easy IP (Phase 2) feature combines DHCP server and relay. With DHCP, 
LAN devices on an IP network (DHCP clients) can request IP addresses from the 
DHCP server. The DHCP server allocates IP addresses from a central pool as 
needed. A DHCP server can be a workstation, PC, or a Cisco router. With the 
DHCP relay feature configured on the router, the routers can relay IP address 
requests from the LAN interface and to the DHCP server as shown in Figure 7-1 
and Ta b l e 7 - 1.
Step 15dsl operating-mode gshdsl symmetric 
annex annexSet the G.SHDSL operating mode, if 
applicable, and select the G.991.2 annex.
Step 16pvc vpi/vciCreate an ATM PVC for each end node with 
which the router communicates.
Step 17encapsulation aal5mux ppp dialer Specify the encapsulation type for the PVC to 
be AAL5MUX PPP and point back to the 
dialer interface. 
Step 18dialer pool-member numberSpecify which dialer pool-member you are 
using.
Step 19no shutdownEnable the interface and configuration 
changes just made to the ATM interface.
Step 20exitExit configuration mode for the ATM 
interface. Command Task 
						

							 
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Chapter 7      Router Feature Configuration
Configuring DHCP
Figure 7-1 Easy IP (Phase 2)–DHCP Server and Relay
Configuring DHCP
The following sections describe how to configure the router as a DHCP client, 
server, or relay.
Configuring DHCP Client Support
Follow these steps to configure the router for DHCP client support:
Step 1Configure the BVI interface by entering the ip address dhcp client-id Ethernet 
0 command. 
Cisco 827 Cisco 3600
AT M
74583
1
3
24
5
Table 7-1 Key for Easy IP (Phase 2)–DHCP Server and Relay
Callout 
Number Description
1 DHCP client
2 Remote office with Cisco 827 router
3 DHCP relay
4 Corporate office with Cisco 3600 router
5 DHCP server 
						

							 
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Configuring DHCP
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Specifying the value client-id ethernet0 means that the MAC address of the 
Ethernet interface is used as the client ID when the DHCP request is sent. 
Otherwise, the MAC address of the BVI interface is used as the client ID.
Step 2Configure NAT:
a.Configure the BVI interface by entering the ip nat outside command.
b.Configure the Ethernet interface by entering the ip nat inside command.
c.Create an access list under NAT by entering the access-list 1 permit ip 
address command to match all Ethernet IP addresses.
d.Configure the source list under NAT by entering the 
ip nat inside source list 1 interface BVI 1 overload command.
Step 3Configure the Cisco router to act as a DHCP server. This step is optional.
a.At the config-if router prompt, enter the ip dhcp pool server name 
command.
b.Enter the import all command to have the Cisco router retrieve the Microsoft 
Windows nameserver (WINS) and domain name system (DNS) server 
addresses for name resolution.
Configuration Example
The following example shows a configuration of the DHCP client.
Current configuration:
!
version 12.0
no service pad
service timestamps debug uptime
service timestamps log uptime
no service password-encryption
!
hostname c827
!
!
ip subnet-zero
ip dhcp excluded-address 10.10.10.1
!
ip dhcp pool SERVER
network 10.10.10.0 255.255.255.0 
						

							 
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default-router 10.10.10.1 
import all
! 
bridge irb
interface Ethernet0
ip address 10.10.10.1 255.255.255.0
no ip directed-broadcast
ip nat inside
!
interface ATM0
no ip address
no ip directed-broadcast
no atm ilmi-keepalive
bundle-enable
hold-queue 208 in
!
interface ATM0.1 point-to-point
no ip directed-broadcast
pvc 1/100 
encapsulation aal5snap
!
bridge-group 1
!
interface ATM0.2 point-to-point
ip address 5.0.0.2 255.0.0.0
no ip directed-broadcast
pvc 1/101 
protocol ip 5.0.0.1 broadcast
protocol ip 5.0.0.5 broadcast
encapsulation aal5snap
!
!
interface BVI1
ip address dhcp client-id Ethernet0
no ip directed-broadcast
ip nat outside
!
ip nat inside source list 1 interface BVI1 overload
ip classless
ip route 0.0.0.0 0.0.0.0 BVI1
no ip http server
!
access-list 1 permit 10.10.10.0 0.0.0.255
bridge 1 protocol ieee
bridge 1 route ip
!
voice-port 1
timing hookflash-in 0 
						

							 
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voice-port 2
timing hookflash-in 0
!
voice-port 3
timing hookflash-in 0
!
voice-port 4
timing hookflash-in 0
!
!
line con 0
exec-timeout 0 0
transport input none
stopbits 1
line vty 0 4
password lab
login    
!
scheduler max-task-time 5000
end
Configuring DHCP Server
Follow the steps below to configure the router as a DHCP server, beginning in 
global configuration mode.
Command Task
Step 1ip dhcp pool nameEnter DHCP configuration mode, and create a 
pool of IP addresses that can be assigned to 
DHCP clients.
Step 2network ip-address subnet-maskSpecify a range of IP addresses that can be 
assigned to the DHCP clients.
Step 3domain-name domain nameConfigure the domain name.
Step 4dns-server ip-addressDesignate the router as the default router, and 
specify an IP address.
Step 5netbios-name-server ip-addressConfigure the netbios name server.
Step 6default-router ip-addressConfigure the DNS server.