Solved: Re: EIGRP neighbor UP, routes showing but ping working only on one direction! - Page 2

mazzz · ‎10-10-2018

Hi guys,

I have my two Cisco L3 switches connected via a L2 link on which I activated EIGRP 10 and the neighborship is up.

vlan 50 : 172.17.192.128/25 --------[L3_SW_2] Fa0/24====L2====Fa1/0/48 [L3_SW_1] -------- vlan 50 : 172.17.192.0/25

The interco subnet of the L2 link is : 192.168.1.200/30

From L3_SW_2, I am able to ping an IP of the vlan 50 behind L3_SW_L1 : 172.17.192.24.

But the reverse doesn't work (I tried to ping from L3_SW_2 an IP behind SW_1 : 172.17.192.130 which desn't work).

L3_SW_2#sh ip route eigr
.... output omitted ....
Gateway of last resort is 172.17.192.210 to network 0.0.0.0

      172.17.0.0/16 is variably subnetted, 3 subnets, 2 masks
D        172.17.192.0/25
           [90/28416] via 192.168.1.201, 02:00:21, FastEthernet0/24
L3_SW_2#

L3_SW_1#sh ip eigrp neighbors
EIGRP-IPv4 Neighbors for AS(10)
H   Address                 Interface              Hold Uptime   SRTT   RTO Q Seq
                                                   (sec)         (ms)       Cnt Num
0   192.168.1.202           Fa1/0/48                 14 01:57:25    7   100 0 29
L3_SW_2#

L3_SW_2#sh ip eigrp neighbors
EIGRP-IPv4 Neighbors for AS(10)
H   Address                 Interface       Hold Uptime   SRTT   RTO Q Seq
                                            (sec)         (ms)       Cnt Num
0   192.168.1.201           Fa0/24            14 01:58:10    1   200 0 34
L3_SW_2#

L3_SW_2#sh ip arp
Protocol Address          Age (min) Hardware Addr   Type   Interface
Internet 172.17.192.130          1   000c.297e.8f75 ARPA   Vlan50
Internet 172.17.192.140          9   c81f.66d7.c878 ARPA   Vlan50
Internet 172.17.192.200          -   9caf.cad2.c0c4 ARPA   Vlan50
Internet 172.17.192.210        200   4c4e.3539.77c1 ARPA   Vlan50
Internet 192.168.1.201         121   b8be.bf9e.3b44 ARPA   FastEthernet0/24
Internet 192.168.1.202           -   9caf.cad2.c0c1 ARPA   FastEthernet0/24

L3_SW_1#sh ip arp
Protocol Address          Age (min) Hardware Addr   Type   Interface
Internet 10.170.124.121          -   b8be.bf9e.3b42 ARPA   Vlan30
Internet 10.170.124.122         22   0025.90ca.1f62 ARPA   Vlan30
Internet 172.17.192.8          160   0026.b981.a277 ARPA   Vlan50
Internet 172.17.192.9            0   0026.b981.a26f ARPA   Vlan50

L3_SW_1#sh run | s eigrp
router eigrp 10
network 172.17.192.0 0.0.0.127
network 192.168.1.200 0.0.0.3
passive-interface default
no passive-interface FastEthernet1/0/48
no passive-interface Vlan50

L3_SW_2#sh run | s eigrp
router eigrp 10
network 172.17.192.128 0.0.0.127
network 192.168.1.200 0.0.0.3
passive-interface default
no passive-interface FastEthernet0/24
no passive-interface Vlan50

I need your help on this. Please ask me if you need other command outputs.

Thank you,

mazzz · ‎10-10-2018

See Dan,

The problem is not with .8 (VLAN 172.17.192.0/25) on SW_1 but with the VLAN 172.17.192.128/25 which is behind SW_2.
I am able to ping .8 / .9 and other IPs from SW2 via the L2 link (VLAN 50 172.17.192.0/25 is behind SW1) but,
... I am not able to ping the 172.17.192.130 from SW1 via L2 link (VLAN 50172.17.192.128/25) is bheind SW2.

A traceroute to IP 172.17.192.130 from SW1 dies at the EIGRP neighboring address (192.168.1.202) on SW2:
It looks like it desn't know the route to 172.17.192.130 which is completely false (see the topology far below):

L3_SW_1#traceroute 172.17.192.130
Type escape sequence to abort.
Tracing the route to 172.17.192.130
VRF info: (vrf in name/id, vrf out name/id)
1 192.168.1.202 0 msec 9 msec 8 msec
2 * * *
3 * * *
4 * * *

L3_SW_2#sh ip eigrp topology
EIGRP-IPv4 Topology Table for AS(10)/ID(192.168.1.202)
Codes: P - Passive, A - Active, U - Update, Q - Query, R - Reply,
r - reply Status, s - sia Status

P 172.17.192.128/25, 1 successors, FD is 2816
via Connected, Vlan50
P 192.168.1.200/30, 1 successors, FD is 28160
via Connected, FastEthernet0/24
P 172.17.192.0/25, 1 successors, FD is 28416
via 192.168.1.201 (28416/2816), FastEthernet0/24