Rick Graziani Cabrillo College graziani@cabrillo.edu Fine Tuning EIGRP Rick Graziani Cabrillo College graziani@cabrillo.edu

EIGRP: IPv4 Automatic Summarization Rick Graziani Cabrillo College graziani@cabrillo.edu

EIGRP (IPv4) Network Topology

R1# show running-config interface GigabitEthernet0/0 ip address 172.16.1.1 255.255.255.0 ! interface Serial0/0/0 bandwidth 64 ip address 172.16.3.1 255.255.255.252 clock rate 64000 interface Serial0/0/1 ip address 192.168.10.5 router eigrp 1 eigrp router-id 1.1.1.1 network 172.16.0.0 network 192.168.10.0

R2# show running-config interface GigabitEthernet0/0 ip address 172.16.2.1 255.255.255.0 ! interface Serial0/0/0 bandwidth 64 ip address 172.16.3.2 255.255.255.252 interface Serial0/0/1 bandwidth 1024 ip address 192.168.10.9 clock rate 64000 interface Serial0/1/0 ip address 209.165.200.225 255.255.255.224 router eigrp 1 eigrp router-id 2.2.2.2 network 172.16.0.0 network 192.168.10.8 0.0.0.3

R3# show running-config interface GigabitEthernet0/0 ip address 192.168.1.1 255.255.255.0 ! interface Serial0/0/0 ip address 192.168.10.6 255.255.255.252 clock rate 64000 interface Serial0/0/1 bandwidth 1024 ip address 192.168.10.10 router eigrp 1 eigrp router-id 3.3.3.3 network 192.168.1.0 network 192.168.10.4 0.0.0.3 network 192.168.10.8 0.0.0.3

Route Summarization Route summarization: Groups contiguous networks together Advertises them using a single summarized route Summarization: Decreases the number of entries in routing updates Reduces bandwidth utilization for routing updates Results in faster routing table lookups. EIGRP for IPv4 includes both automatic (classful boundary) and manual summarization EIGRP for IPv6 is only manual summarization as there are no classes in IPv6.

I’m an EIGRP for IPv4 router configured for automatic summarization. Automatic Summarization at Classful Network Boundary I’m an EIGRP for IPv4 router configured for automatic summarization. IPv4 Routing Table 172.16.1.0/24 172.16.2.0/24 172.16.3.0/24 172.17.0.0/30 R1 R2 172.16.0.0/16 via R1 Summary Update: 172.16.0.0/16 Classful Networks Class A: 0.0.0.0 to 127.255.255.255 Default Mask: 255.0.0.0 or /8 Class B: 128.0.0.0 to 191.255.255.255 Default Mask: 255.255.0.0 or /16 Class C: 192.0.0.0 to 223.255.255.255 Default Mask: 255.255.255.0 or /24 When enabled, EIGRP summarizes at classful boundaries. EIGRP groups subnets into their Class A, B, or C network address and creates a single entry. Media Description: Use graphic from powerpoint

EIGRP for IPv4 automatic summarization defaults Since IOS 15.0(1)M and 12.2(33), automatic summarization is disabled. IPv6 does not have classful networks so there is no automatic summarization for IPv6. R1(config-router)# no auto-summary Prior, automatic summarization was enabled. R1(config-router)# auto-summary 172.16.1.0/24 172.16.2.0/14 172.16.3.0/24 172.16.1.0/24 172.16.2.0/14 172.16.3.0/24 R3# show ip route eigrp <Output omitted> 172.16.0.0/16 is variably subnetted, 3 subnets, 2 masks D 172.16.1.0/24 [90/2170112] via 192.168.10.5, 02:21:10, Serial0/0/0 D 172.16.2.0/24 [90/3012096] via 192.168.10.9, 02:21:10, Serial0/0/1 D 172.16.3.0/30 [90/41024000] via 192.168.10.9, 02:21:10, Serial0/0/1 [90/41024000] via 192.168.10.5, 02:21:10, Serial0/0/0 R3#

Verifying EIGRP Automatic Summarization R1# show ip protocols *** IP Routing is NSF aware *** Routing Protocol is "eigrp 1" Outgoing update filter list for all interfaces is not set Incoming update filter list for all interfaces is not set Default networks flagged in outgoing updates Default networks accepted from incoming updates EIGRP-IPv4 Protocol for AS(1) Metric weight K1=1, K2=0, K3=1, K4=0, K5=0 <Output omitted> Automatic Summarization: disabled Maximum path: 4 Routing for Networks: 172.16.0.0 192.168.10.0 Media Description: Use graphic from powerpoint

When automatic summarization is enabled: EIGRP for IPv4 automatically summarizes network addresses between different major class networks. 172.16.0.0/16 172.16.0.0/16 R1(config)# router eigrp 1 R1(config-router)# auto-summary R1(config-router)# *Mar 9 19:40:19.342: %DUAL-5-NBRCHANGE: EIGRP-IPv4 1: Neighbor 192.168.10.6 (Serial0/0/1) is resync: summary configured *Mar 9 19:40:19.342: %DUAL-5-NBRCHANGE: EIGRP-IPv4 1: Neighbor 192.168.10.6 (Serial0/0/1) is resync: summary up, remove components *Mar 9 19:41:03.630: %DUAL-5-NBRCHANGE: EIGRP-IPv4 1: Neighbor 192.168.10.6 (Serial0/0/1) is resync: peer graceful-restart R2(config)# router eigrp 1 R2(config-router)# auto-summary R3(config)# router eigrp 1 R3(config-router)# auto-summary

Verifying Auto-Summary: Routing Table Automatic Summarization Disabled R3# show ip route eigrp <Output omitted> 172.16.0.0/16 is variably subnetted, 3 subnets, 2 masks D 172.16.1.0/24 [90/2170112] via 192.168.10.5, 02:21:10, Serial0/0/0 D 172.16.2.0/24 [90/3012096] via 192.168.10.9, 02:21:10, Serial0/0/1 D 172.16.3.0/30 [90/41024000] via 192.168.10.9, 02:21:10, Serial0/0/1 [90/41024000] via 192.168.10.5, 02:21:10, Serial0/0/0 Automatic Summarization Enabled R3# show ip route eigrp <Output omitted> D 172.16.0.0/16 [90/2170112] via 192.168.10.5, 00:12:05, Serial0/0/0 192.168.10.0/24 is variably subnetted, 5 subnets, 3 masks D 192.168.10.0/24 is a summary, 00:11:43, Null0 Media Description: Use graphic from powerpoint

Verifying Auto-Summary: Topology Table Feasible Successor Verifying Auto-Summary: Topology Table 172.16.0.0/16 Successor 172.16.0.0/16 R3# show ip eigrp topology all-links P 172.16.0.0/16, 1 successors, FD is 2170112, serno 9 via 192.168.10.5 (2170112/2816), Serial0/0/0 via 192.168.10.9 (3012096/2816), Serial0/0/1 <Output omitted> Successor Feasible Successor Media Description: Use graphic from powerpoint

Verifying Auto-Summary: show ip protocols 192.168.10.0/24 172.16.0.0/16 R1# show ip protocols *** IP Routing is NSF aware *** <Output omitted> Automatic Summarization: enabled 192.168.10.0/24 for Gi0/0, Se0/0/0 Summarizing 2 components with metric 2169856 172.16.0.0/16 for Se0/0/1 Summarizing 3 components with metric 2816 Media Description: Use graphic from powerpoint

172.16.0.0/16 is variably subnetted, 6 subnets, 4 masks The purpose of the Null0 summary route is to prevent routing loops for destinations that are included in the summary, but do not actually exist in the routing table. "If I don't know the subnet, then I will drop the packet because the subnet doesn't exist." 192.168.10.0/24 172.16.0.0/16 R1# show ip route 172.16.0.0/16 is variably subnetted, 6 subnets, 4 masks D 172.16.0.0/16 is a summary, 00:03:06, Null0 C 172.16.1.0/24 is directly connected, GigabitEthernet0/0 L 172.16.1.1/32 is directly connected, GigabitEthernet0/0 D 172.16.2.0/24 [90/40512256] via 172.16.3.2, 00:02:52, Serial0/0/0 C 172.16.3.0/30 is directly connected, Serial0/0/0 L 172.16.3.1/32 is directly connected, Serial0/0/0 D 192.168.1.0/24 [90/2170112] via 192.168.10.6, 00:02:51, Serial0/0/1 192.168.10.0/24 is variably subnetted, 4 subnets, 3 masks D 192.168.10.0/24 is a summary, 00:02:52, Null0 <output omitted> Media Description: Use graphic from powerpoint

Routing Update: Default Route Example of a Routing Loop 9 Routing loop 7 I have a summary route for 172.16.0.0/16. I will send packets for 172.16.4.10 to Router B. 8 I have a default route 0.0.0.0/0. I will send packets for 172.16.4.10 to Router A. IPv4 Routing Table IPv4 Routing Table 2 Routing Update: Default Route 0.0.0.0/0 via RouterA 172.16.1.0/24 172.16.2.0/24 172.16.3.0/24 1 0.0.0.0/0 via ISP 172.16.0.0/16 Via RouterB 3 RouterA RouterB 5 4 Summarized Update: 172.16.0.0/16 6 Internet ISP Media Description: Use graphic from powerpoint

Routing Update: Default Route Null0 Route is used for Loop Prevention 9 8 I have a summary route for 172.16.0.0/16. I will send packets for 172.16.4.10 to Router B. I have a summary route for 172.16.0.0/16 via Null0. I drop packets for 172.16.4.10. IPv4 Routing Table IPv4 Routing Table 2 Routing Update: Default Route 0.0.0.0/0 via RouterA 172.16.1.0/24 172.16.2.0/24 172.16.3.0/24 172.16.0.0/16 via Null0 1 0.0.0.0/0 via ISP 172.16.0.0/16 Via RouterB 3 RouterA RouterB 6 4 Summarized Update: 172.16.0.0/16 7 5 Internet ISP Media Description: Use graphic from powerpoint

EIGRP: IPv4 Automatic Summarization Rick Graziani Cabrillo College graziani@cabrillo.edu

EIGRP: IPv4 Manual Summarization Rick Graziani Cabrillo College graziani@cabrillo.edu

Manual Route Summarization EIGRP manual summary routes used with or without auto-summary EIGRP is a classless routing protocol - includes the subnet mask in the routing updates Manual summarization can include supernet routes. A supernet is an aggregation of multiple major classful network addresses EIGRP manual summarization is configured on a specific EIGRP interface: ip summary-address eigrp as-number network-address subnet-mask

Loopback’s Added for Demonstration R3(config)# interface loopback 2 R3(config-if)# ip add 192.168.2.1 255.255.255.0 R3(config-if)# exit R3(config)# interface loopback 3 R3(config-if)# ip add 192.168.3.1 255.255.255.0 R3(config)# router eigrp 1 R3(config-router)# network 192.168.2.0 R3(config-router)# network 192.168.3.0

Additional Routes Verified on R1 and R2 R1# show ip route <Output omitted> D 192.168.1.0/24 [90/2170112] via 192.168.10.6, 00:47:39, Serial0/0/1 D 192.168.2.0/24 [90/2297856] via 192.168.10.6, 00:08:09, Serial0/0/1 D 192.168.3.0/24 [90/2297856] via 192.168.10.6, 00:08:04, Serial0/0/1 R2# show ip route <Output omitted> D 192.168.1.0/24 [90/3012096] via 192.168.10.10, 00:47:58, Serial0/0/1 D 192.168.2.0/24 [90/3139840] via 192.168.10.10, 00:08:28, Serial0/0/1 D 192.168.3.0/24 [90/3139840] via 192.168.10.10, 00:08:23, Serial0/0/1 Media Description: Use graphic from powerpoint

Calculating a Summary Route Use the same method is used to determine summary static routes: Write out the networks to be summarized in binary. To find the subnet mask for summarization, start with the far left bit. Working from left to right, find all the bits that match consecutively. ip summary-address eigrp 1 192.168.0.0 255.255.252.0 Media Description: Use graphic from E2-9.5.3.1, “R3 Summary route” button as modified in powerpoint

Calculating a Summary Route 192.168.0.0/22 192.168.0.0/22 Calculating a Summary Route R3(config)# interface serial 0/0/0 R3(config-if)# ip summary-address eigrp 1 192.168.0.0 255.255.252.0 R3(config)# interface serial 0/0/1 Media Description: Use graphic from E2-9.5.3.1, “R3 Summary route” button as modified in powerpoint

Verifying Summary Route Received on R1 and R2 Note: A Null Summary Route is added to R3’s routing table (not shown here). 192.168.0.0/22 192.168.0.0/22 Verifying Summary Route Received on R1 and R2 R1# show ip route <Output omitted> D 192.168.0.0/22 [90/2170112] via 192.168.10.6, 01:53:19, Serial0/0/1 R1# R2# show ip route <Output omitted> D 192.168.0.0/22 [90/3012096] via 192.168.10.10, 01:53:33, Serial0/0/1 R2# Media Description: Use graphic from powerpoint

EIGRP: IPv4 Manual Summarization Rick Graziani Cabrillo College graziani@cabrillo.edu

EIGRP: IPv6 Manual Summarization Rick Graziani Cabrillo College graziani@cabrillo.edu

EIGRP for IPv6 Topology

Configure Loopbacks and enable EIGRP for IPv6 on each interface R3(config)# interface loopback 11 R3(config-if)# ipv6 address 2001:db8:acad:1::1/64 R3(config-if)# ipv6 eigrp 2 R3(config-if)# exit R3(config)# interface loopback 12 R3(config-if)# ipv6 address 2001:db8:acad:2::1/64 R3(config)# interface loopback 13 R3(config-if)# ipv6 address 2001:db8:acad:3::1/64 R3(config)# interface loopback 14 R3(config-if)# ipv6 address 2001:db8:acad:4::1/64

Manual Route Summarization EIGRP manual summarization can also be configured on IPv6. Configured on a specific EIGRP interface: ipv6 summary-address eigrp as-number prefix/prefix-length

Identify Where the Addresses Differ Media Description: Use the media from E2-6.3.2.1-A

Convert the Section from Hex to Binary Media Description: Use the media from E2-6.3.2.1-A

Count the # of Left-Most Matching Bits Add Zero Bits Media Description: Use the media from E2-6.3.2.1-A

Convert the Binary Section Back to Hex 2001:0DB8:ACAD:0000::/61 or 2001:0DB8:ACAD:0::/61 2001:0DB8:ACAD::/61 Media Description: Use the media from E2-6.3.2.1-A

Configuration and Verification of EIGRP for IPv6 Manual Summary Route A Null Summary Route is added to R3’s routing table. 2001:db8:acad::/61 Configuration and Verification of EIGRP for IPv6 Manual Summary Route 2001:db8:acad::/61 R3(config)# interface serial 0/0/0 R3(config-if)# ipv6 summary-address eigrp 2 2001:db8:acad::/61 R3(config-if)# exit R3(config)# interface serial 0/0/1 R3(config-if)# end R3# show ipv6 route D 2001:DB8:ACAD::/61 [5/128256] via Null0, directly connected <Output omitted> Media Description: Use graphic from powerpoint

Verification of EIGRP for IPv6 Manual Summary Route 2001:db8:acad::/61 2001:db8:acad::/61 Verification of EIGRP for IPv6 Manual Summary Route R1# show ipv6 route | include 2001:DB8:ACAD: D 2001:DB8:ACAD::/61 [90/2297856] R1# Media Description: Use graphic from powerpoint

EIGRP: IPv6 Manual Summarization Rick Graziani Cabrillo College graziani@cabrillo.edu

EIGRP: Propagating a Default Route Rick Graziani Cabrillo College graziani@cabrillo.edu

EIGRP for IPv4: Default Route to ISP

Propagating a Default Route Default Static Route Propagating a Default Route Redistribute static Redistribute static R2(config)# ip route 0.0.0.0 0.0.0.0 209.165.200.254 R2(config)# router eigrp 1 R2(config-router)# redistribute static To create a default static route: ip route 0.0.0.0 0.0.0.0 next-hop | interface To propagate the default route into the EIGRP AS, use the: redistribute static router configuration command. Note: EIGRP also supports propagating the default route using the ip default-network network-number global configuration command, but not recommended.

R2’s Default Static Route Redistribute static Redistribute static R2’s Default Static Route R2# show ip route | include 0.0.0.0 Gateway of last resort is 0.0.0.0 to network 0.0.0.0 S* 0.0.0.0/0 via 209.165.200.254, 00:25:23, Serial0/1/0 R2# show ip protocols *** IP Routing is NSF aware *** Routing Protocol is "eigrp 1" Outgoing update filter list for all interfaces is not set Incoming update filter list for all interfaces is not set Default networks flagged in outgoing updates Default networks accepted from incoming updates Redistributing: static EIGRP-IPv4 Protocol for AS(1) <Output omitted> Media Description: Use graphic from powerpoint

Verifying Default Route on R1 and R3 Default Static Route Redistribute static Redistribute static Verifying Default Route on R1 and R3 R1# show ip route | include 0.0.0.0 Gateway of last resort is 192.168.10.6 to network 0.0.0.0 D*EX 0.0.0.0/0 [170/3651840] via 192.168.10.6, 00:25:23, Serial0/0/1 R1# R3# show ip route | include 0.0.0.0 Gateway of last resort is 192.168.10.9 to network 0.0.0.0 D*EX 0.0.0.0/0 [170/3139840] via 192.168.10.9, 00:27:17, Serial0/0/1 R3# Media Description: Use graphic from powerpoint

EIGRP for IPv6: Default Route

R2 IPv6 Static Default Route Configuration and Propagation Default Static Route Redistribute static Redistribute static R2 IPv6 Static Default Route Configuration and Propagation R2(config)# ipv6 route ::/0 2001:db8:feed:a002::2 R2(config)# ipv6 router eigrp 2 R2(config-router)# redistribute static Verifying Default Route on R1 and R3 R1# show ipv6 route Codes: C - ... EX - EIGRP external EX ::/0 [170/3523840] via FE80::3, Serial0/0/1 Media Description: Use graphic from powerpoint

Alternative method using a summary route Default Static Route Alternative method using a summary route Summary Route Summary Route R2(config)# ipv6 route ::/0 2001:db8:feed:a002::2 R2(config)# interface serial 0/1/0 R2(config-if)# ipv6 summary-address eigrp 2 ::/0 R2(config)# ip route 0.0.0.0 0.0.0.0 209.165.200.254 R2(config)# interface serial 0/1/0 R2(config-if)# ip summary-address eigrp 1 0.0.0.0 0.0.0.0 Media Description: Use graphic from powerpoint

EIGRP: Propagating a Default Route Rick Graziani Cabrillo College graziani@cabrillo.edu

EIGRP: Bandwidth Utilization Rick Graziani Cabrillo College graziani@cabrillo.edu

EIGRP ip bandwith-percent By default, EIGRP is set to use up to 50% of the bandwidth of an interface to exchange routing information. The ip bandwidth-percent eigrp command or the ipv6 bandwidth-percent eigrp command can be configured to control the amount of bandwidth available to EIGRP. This is not the same as the bandwidth command. However, this command relies on the value set by the bandwidth command.

Configuring Bandwidth Utilization with EIGRP for IPv4 R1(config)# interface serial 0/0/0 R1(config-if)# bandwidth 64 R1(config-if)# ip bandwidth-percent eigrp 1 40 R1(config-if)# R2(config)# interface serial 0/0/0 R2(config-if)# bandwidth 64 R2(config-if)# ip bandwidth-percent eigrp 1 40 R2(config-if)# Media Description: Use graphic from powerpoint

Configuring Bandwidth Utilization with EIGRP for IPv6 64 kb/s Configuring Bandwidth Utilization with EIGRP for IPv6 R1(config)# interface serial 0/0/0 R1(config-if)# ipv6 bandwidth-percent eigrp 2 40 R1(config-if)# R2(config)# interface serial 0/0/0 R2(config-if)# ipv6 bandwidth-percent eigrp 2 40 R2(config-if)# Media Description: Use graphic from powerpoint

EIGRP: Bandwidth Utilization Rick Graziani Cabrillo College graziani@cabrillo.edu

EIGRP: Hello and Hold Timers Rick Graziani Cabrillo College graziani@cabrillo.edu

Configuring Hello Intervals and Hold Times Router(config-if)# ip hello-interval eigrp as-number seconds Router(config-if)# ip hold-time eigrp as-number seconds Hello intervals and hold times do not have to match with other EIGRP routers to establish adjacencies. We will see later, OSPF’s Hello and other timers do need to match between neighbors. Range from 1 to 65,535 If you change the hello interval, make sure that you also change the hold time to a value greater than the hello interval. Otherwise, neighbor adjacency will go down after the hold time expires and before the next hello interval. Hello intervals and hold times are configurable on a per-interface basis and do not have to match with other EIGRP routers to establish adjacencies. We will see later, OSPF’s Hello and other timers do need to match. The seconds value for both hello and holdtime intervals can range from 1 to 65,535 If you change the hello interval, make sure that you also change the hold time to a value equal to or greater than the hello interval. Otherwise, neighbor adjacency will go down after the hold time expires and before the next hello interval.

Configuring EIGRP for IPv4 Hello and Hold Timers R1(config)# interface serial 0/0/0 R1(config-if)# ip hello-interval eigrp 1 60 R1(config-if)# ip hold-time eigrp 1 180 R2(config)# interface serial 0/0/0 R2(config-if)# ip hello-interval eigrp 1 60 R2(config-if)# ip hold-time eigrp 1 180 Media Description: Use graphic from powerpoint Use Table from E2-9.1.5.1

Configuring EIGRP for IPv6 Hello and Hold Timers R1(config)# inter serial 0/0/0 R1(config-if)# ipv6 hello-interval eigrp 2 60 R1(config-if)# ipv6 hold-time eigrp 2 180 R2(config)# inter serial 0/0/0 R2(config-if)# ipv6 hello-interval eigrp 2 60 R2(config-if)# ipv6 hold-time eigrp 2 180 Media Description: Use graphic from powerpoint

EIGRP: Hello and Hold Timers Rick Graziani Cabrillo College graziani@cabrillo.edu

EIGRP: Load Balancing Rick Graziani Cabrillo College graziani@cabrillo.edu

Referred to as “equal-cost load balancing”. R3# show ip protocols *** IP Routing is NSF aware *** Routing Protocol is "eigrp 1" <Output omitted> Distance: internal 90 external 170 Maximum path: 4 Maximum hopcount 100 Maximum metric variance 1 Automatic Summarization: disabled Address Summarization: 192.168.0.0/22 for Se0/0/0, Se0/0/1 Summarizing 3 components with metric 2816 Routes with a metric equal to the minimum metric are installed in the routing table. Referred to as “equal-cost load balancing”. All IP routing protocols on Cisco routers can perform equal-cost load balancing. The maximum-paths maximum-path command can be used to allow up to 6 equal-cost paths. Default is 4. Setting the maximum-path option to 1 disables load balancing. Media Description: Use graphic from powerpoint

R3 has equal cost paths to 172. 16. 3 R3 has equal cost paths to 172.16.3.0/30 because 64 kb/s is the slowest bandwidth used for the metric. R3# show ip route eigrp <Output omitted> Gateway of last resort is 192.168.10.9 to network 0.0.0.0 D*EX 0.0.0.0/0 [170/3139840] via 192.168.10.9, 00:14:24, Serial0/0/1 172.16.0.0/16 is variably subnetted, 3 subnets, 2 masks D 172.16.1.0/24 [90/2170112] via 192.168.10.5, 00:14:28, Serial0/0/0 D 172.16.2.0/24 [90/3012096] via 192.168.10.9, 00:14:24, Serial0/0/1 D 172.16.3.0/30 [90/41024000] via 192.168.10.9, 00:14:24, Serial0/0/1 [90/41024000] via 192.168.10.5, 00:14:24, Serial0/0/0 D 192.168.0.0/22 is a summary, 00:14:40, Null0 Media Description: Use graphic from powerpoint

R3’s IPv6 Routing Table R3# show ipv6 route eigrp <Output omitted> EX ::/0 [170/3011840] via FE80::2, Serial0/0/1 D 2001:DB8:ACAD::/48 [5/128256] via Null0, directly connected D 2001:DB8:CAFE:1::/64 [90/2170112] via FE80::1, Serial0/0/0 D 2001:DB8:CAFE:2::/64 [90/3012096] D 2001:DB8:CAFE:A001::/64 [90/41024000] R3# Media Description: Use graphic from powerpoint

EIGRP: Load Balancing Rick Graziani Cabrillo College graziani@cabrillo.edu

EIGRP: Authentication Rick Graziani Cabrillo College graziani@cabrillo.edu

Router Authentication Many routing protocols support authentication. This means that a router authenticates the source of each routing update packet that it receives. Without authentication, an attacker could introduce different or conflicting route information to corrupt the router resulting in a DoS attack. Neighbor router authentication (also called route authentication) can be configured such that routers only participate in routing based on predefined passwords. By default, no authentication is used for routing protocol packets. When neighbor router authentication has been configured on a router, the router authenticates the source of each routing update packet that it receives, which is accomplished by the exchange of an authentication key (also called a password) that is known to both the sending and the receiving router. There are two types of authentication: simple password authentication (also called plain text authentication) and MD5 authentication. Simple password authentication is supported by Integrated System-Integrated System (IS-IS), Open Shortest Path First (OSPF), and Routing Information Protocol version 2 (RIPv2). MD5 authentication is supported by OSPF, RIPv2, Border Gateway Protocol (BGP), and EIGRP. NOTE: Authentication for EIGRP, OSPF, and BGP is covered in this course.

EIGRP MD5 Authentication EIGRP supports MD5 authentication. Router authenticates the source of each routing update packet that it receives. Configure a “key” (password) and key-id; each participating neighbor must have same key configured. EIGRP neighbor authentication (also called neighbor router authentication or route authentication) can be configured such that routers can participate in routing based on predefined passwords. By default, no authentication is used for EIGRP packets. EIGRP can be configured to use MD5 authentication. When neighbor authentication has been configured on a router, the router authenticates the source of each routing update packet that it receives. For EIGRP MD5 authentication, an authenticating key (sometimes referred to as a password) and a key-id must be configured on both the sending and the receiving router.

EIGRP MD5 Authentication Example R3 needs to send an update to R1. Routing Updates Authenticated Compare Signatures Signatures Match! R3 processes the routing update (data) and key using MD5 to compute a hash signature. The update is sent to R1 and includes the signature. R3 repeats the MD5 process using its own key and the received data.

Step 1: Create a Keychain Router(config)# key chain name-of-chain Router(config-keychain)# key key-id Router(config-keychain-key)# key-string key-string-text Before authentication is enabled, create a keychain and key. Multiple keys can be configured. Specify the key ID using a range of keys (0 to 2,147,483,647). Recommended to use the same key number on all routers. Enable EIGRP authentication on an interface and identify the keychain and key to use. Specify the keychain that should be used for authentication. The keychain and the routing update are processed using the MD5 algorithm to produce a unique signature. Step 2: Configure EIGRP Authentication Using Keychain and Key Router(config)# interface type number Router(config-if)# ip authentication mode eigrp as-number md5 Router(config-if)# ip authentication key-chain eigrp as-number name-of-chain Media Description: Use graphic from powerpoint

Similar configuration for R3. Configuring EIGRP MD5 Authentication on R1 Similar configuration for R3. R1(config)# key chain EIGRP_KEY R1(config-keychain)# key 1 R1(config-keychain-key)# key-string cisco123 R1(config-keychain-key)# exit R1(config-keychain)# exit R1(config)# interface serial 0/0/0 R1(config-if)# ip authentication mode eigrp 1 md5 R1(config-if)# ip authentication key-chain eigrp 1 EIGRP_KEY R1(config-if)# exit R1(config)# interface serial 0/0/1 R2(config)# key chain EIGRP_KEY R2(config-keychain)# key 1 R2(config-keychain-key)# key-string cisco123 R2(config-keychain-key)# exit R2(config-keychain)# exit R2(config)# interface serial 0/0/0 R2(config-if)# ip authentication mode eigrp 1 md5 R2(config-if)# ip authentication key-chain eigrp 1 EIGRP_KEY R2(config-if)# exit R2(config)# interface serial 0/0/1 Media Description: Use graphic from powerpoint

Configuring EIGRP for IPv6 MD5 Authentication on R1 R1(config)# key chain EIGRP_IPV6_KEY R1(config-keychain)# key 1 R1(config-keychain-key)# key-string cisco123 R1(config-keychain-key)# exit R1(config-keychain)# exit R1(config)# interface serial 0/0/0 R1(config-if)# ipv6 authentication mode eigrp 2 md5 R1(config-if)# ipv6 authentication key-chain eigrp 2 EIGRP_IPV6_KEY R1(config-if)# exit R1(config)# interface serial 0/0/1 R1(config-if)# Media Description: Use graphic from powerpoint

Verify EIGRP MD5 Authentication on R1 R1# show ip eigrp neighbors EIGRP-IPv4 Neighbors for AS(1) H Address Interface Hold Uptime SRTT RTO Q Seq (sec) (ms) Cnt Num 1 172.16.3.2 Se0/0/0 140 03:28:12 96 2340 0 23 0 192.168.10.6 Se0/0/1 14 03:28:27 49 294 0 24 R2# show ip eigrp neighbors EIGRP-IPv4 Neighbors for AS(1) H Address Interface Hold Uptime SRTT RTO Q Seq (sec) (ms) Cnt Num 1 172.16.3.1 Se0/0/0 136 00:22:50 1046 5000 0 32 0 192.168.10.10 Se0/0/1 10 07:51:37 62 372 0 35 R3# show ip eigrp neighbors EIGRP-IPv4 Neighbors for AS(1) H Address Interface Hold Uptime SRTT RTO Q Seq (sec) (ms) Cnt Num 0 192.168.10.5 Se0/0/0 14 00:21:26 1297 5000 0 33 1 192.168.10.9 Se0/0/1 14 07:51:50 43 258 0 36 Media Description: Use graphic from powerpoint

EIGRP: Authentication Rick Graziani Cabrillo College graziani@cabrillo.edu

EIGRP: Troubleshooting Rick Graziani Cabrillo College graziani@cabrillo.edu

EIGRP Troubleshooting Commands Several commands that are useful when troubleshooting an EIGRP network. show ip eigrp neighbors command verifies that the router recognizes its neighbors. show ip route command verifies that the router learned the route to a remote network through EIGRP. show ip protocols command verifies the EIGRP configured values for various properties of any enabled routing protocols. Similar commands and troubleshooting criteria also apply to EIGRP for IPv6. show ipv6 eigrp neighbors show ipv6 route show ipv6 protocols

Diagnosing EIGRP Connectivity Issues Media Description: Use graphic from ICND2 p. 424

Troubleshooting Neighbor Issues The equivalent command used with EIGRP for IPv6 is: show ipv6 interface brief Troubleshoot EIGRP Neighbor Issues R1# show ip interface brief Interface IP-Address OK? Method Status Protocol GigabitEthernet0/0 172.16.1.1 YES manual up up Serial0/0/0 172.16.3.1 YES manual up up Serial0/0/1 192.168.10.5 YES manual up up R1# ping 172.16.3.2 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 172.16.3.2, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 28/28/28 ms R1# Media Description: Use graphic from powerpoint

Troubleshoot EIGRP Neighbor Issues The equivalent command used with EIGRP for IPv6 is: show ipv6 protocols Troubleshoot EIGRP Neighbor Issues R1# show ip protocols *** IP Routing is NSF aware *** Routing Protocol is "eigrp 1“ R2# show ip protocols *** IP Routing is NSF aware *** Routing Protocol is "eigrp 1“ 31# show ip protocols *** IP Routing is NSF aware *** Routing Protocol is "eigrp 1“ Media Description: Use graphic from powerpoint

Troubleshoot EIGRP Neighbor Issues The equivalent command used with EIGRP for IPv6 is: show ipv6 eigrp interfaces Troubleshoot EIGRP Neighbor Issues R1# show ip eigrp interfaces EIGRP-IPv4 Interfaces for AS(1) Xmit Queue PeerQ Mean Pacing Time Multicast Pending Interface Peers Un/Reliable Un/Reliable SRTT Un/Reliable Flow Timer Routes Gi0/1 0 0/0 0/0 0 0/0 0 0 Se0/0/0 1 0/0 0/0 1295 0/23 6459 0 Se0/0/1 1 0/0 0/0 1044 0/15 5195 0 R1# Media Description: Use graphic from powerpoint

Troubleshoot EIGRP Neighbor Issues The equivalent command used with EIGRP for IPv6 is: show ipv6 protocols Troubleshoot EIGRP Neighbor Issues R1# show ip protocols *** IP Routing is NSF aware *** Routing Protocol is "eigrp 1" <Output omitted> Routing for Networks: 172.16.0.0 192.168.10.0 Passive Interface(s): GigabitEthernet0/0 Routing Information Sources: Gateway Distance Last Update 192.168.10.6 90 00:42:31 172.16.3.2 90 00:42:31 Distance: internal 90 external 170 Media Description: Use graphic from powerpoint

Troubleshoot EIGRP Neighbor Issues R1# show running-config | section eigrp 1 router eigrp 1 network 172.16.0.0 network 192.168.10.0 passive-interface GigabitEthernet0/0 eigrp router-id 1.1.1.1 R1# Media Description: Use graphic from powerpoint

Troubleshooting A Passive Interface The equivalent command used with EIGRP for IPv6 is: show ipv6 protocols Troubleshoot EIGRP Routing Table Issues R2# show ip protocols *** IP Routing is NSF aware *** Routing Protocol is "eigrp 1“ <Output omitted> Routing for Networks: 172.16.0.0 192.168.10.8/30 Passive Interface(s): GigabitEthernet0/0 Routing Information Sources: <output omitted> Make sure passive-interface is on the correct interface or adjacencies will not be formed and routing information will not be distributed. Media Description: Use graphic from powerpoint

Configuring Network to ISP as a Passive Interface R2(config)# router eigrp 1 R2(config-router)# network 209.165.200.0 R2(config-router)# passive-interface serial 0/1/0 R2(config-router)# end R2# show ip eigrp neighbors EIGRP-IPv4 Neighbors for AS(1) H Address Interface Hold Uptime SRTT RTO Q Seq (sec) (ms) Cnt Num 1 172.16.3.1 Se0/0/0 175 01:09:18 80 2340 0 16 0 192.168.10.10 Se0/0/1 11 01:09:33 1037 5000 0 17 Media Description: Use graphic from powerpoint

Verifying Network to ISP is distributed using EIGRP R1# show ip route | include 209.165.200.224 D 209.165.200.224 [90/3651840] via 192.168.10.6, 00:06:02,Ser0/0/1 R1# Media Description: Use graphic from powerpoint

Troubleshooting A Missing Network Statement 10.10.10.0/24 Unreachable from R3 R3# ping 10.10.10.1 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 10.10.10.1, timeout is 2 seconds: ..... Success rate is 0 percent (0/5) R3#

10.10.10.0/24 Unreachable from R3 R1# show ip protocols | begin Routing for Networks Routing for Networks: 172.16.0.0 192.168.10.0 Passive Interface(s): GigabitEthernet0/0 Routing Information Sources: Gateway Distance Last Update 192.168.10.6 90 01:34:19 172.16.3.2 90 01:34:19 Distance: internal 90 external 170 Media Description: Use graphic from powerpoint

R1(config)# router eigrp 1 R1(config-router)# network 10.0.0.0 R3# show ip route | include 10.10.10.0 D 10.10.10.0 [90/2172416] via 192.168.10.5, 00:04:14, Serial0/0/0 R3# R3# ping 10.10.10.1 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 10.10.10.1, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 24/27/28 ms Media Description: Use graphic from powerpoint

Troubleshooting Auto-Summarization The equivalent command used with EIGRP for IPv6 is: show ipv6 route Discontiguous networks - Reachability issues R2# show ip route <Output omitted> 10.0.0.0/8 is subnetted, 1 subnets D 10.0.0.0 [90/3014400] via 192.168.10.10, 00:02:06, Serial0/0/1 [90/3014400] via 172.16.3.1, 00:02:06, Serial0/0/0

R1(config)# router eigrp 1 R1(config-router)# network 10.0.0.0 R1(config-router)# network 172.16.0.0 R1(config-router)# auto-summary R3(config)# router eigrp 1 R3(config-router)# network 10.0.0.0 R3(config-router)# network 192.168.10.0 R3(config-router)# auto-summary

R1# show ip protocols *** IP Routing is NSF aware *** Routing Protocol is "eigrp 1" Automatic Summarization: enabled 10.0.0.0/8 for Se0/0/0 Summarizing 1 component with metric 28160 <Output omitted> R3# show ip protocols *** IP Routing is NSF aware *** Routing Protocol is "eigrp 1" Automatic Summarization: enabled 10.0.0.0/8 for Se0/0/1 Summarizing 1 component with metric 28160 <Output omitted>

R1(config)# router eigrp 1 R1(config-router)# no auto-summary 10.10.10.0/24 10.20.20.0/24 R1(config)# router eigrp 1 R1(config-router)# no auto-summary R3(config)# router eigrp 1 R3(config-router)# no auto-summary R2# show ip route <Output omitted> 10.0.0.0/24 is subnetted, 2 subnets D 10.10.10.0 [90/3014400] via 172.16.3.1, 00:00:27, Serial0/0/0 D 10.20.20.0 [90/3014400] via 192.168.10.10, 00:00:11,Serial0/0/1

EIGRP: Troubleshooting Rick Graziani Cabrillo College graziani@cabrillo.edu