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RIP V2 quetion

biggishbiggish Member Posts: 29 ■□□□□□□□□□
in CCNA & CCENT
Just need to ask this.
I have a home lab with a 1760 router and a 1721 router. They are connected back-to-back. The 1721 receives and dispalys routes learnt from the 1760, and sends regular updates as configured, but the 1760 router doesn't receive routing updates, but sends updates.
As a result, the 1760 doesn't add the routes learnt from the 1721.
Can anyone help me figure out why?

R1_1760#show ip route
Codes: C - connected, S - static, 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
i - IS-IS, su - IS-IS summary, 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
S 192.168.1.0/24 [1/0] via 192.168.100.15
192.168.100.0/26 is subnetted, 2 subnets
C 192.168.100.0 is directly connected, FastEthernet0/0
C 192.168.100.192 is directly connected, Serial0/0






1721#show ip route
Codes: C - connected, S - static, 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
i - IS-IS, su - IS-IS summary, 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
S 192.168.1.0/24 [1/0] via 192.168.100.130
192.168.100.0/26 is subnetted, 3 subnets
R 192.168.100.0 [120/1] via 192.168.100.200, 00:00:17, Serial0
C 192.168.100.128 is directly connected, FastEthernet0
C 192.168.100.192 is directly connected, Serial0
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    NetworkVeteranNetworkVeteran Member Posts: 2,338 ■■■■■■■■□□
    (a) The 1721... sends regular updates... but (b) the 1760 router doesn't receive routing updates
    I'm quite skeptical of both statements. Can you show the debug output to prove them?

    After verifying the above, assuming you were correct, the link between the 1721 and 1760 appears to be unidrectional. You can use ping between the directly connected interfaces to verify, and the fix would involve replacing a cable or transceiver.
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    biggishbiggish Member Posts: 29 ■□□□□□□□□□
    1760#debug ip rip
    RIP protocol debugging is on
    IvanR1_1760#
    May 16 20:54:14.603: RIP: sending v2 update to 224.0.0.9 via Serial0/0 (192.168.100.200)
    May 16 20:54:14.603: RIP: build update entries
    May 16 20:54:14.603: 192.168.100.0/26 via 0.0.0.0, metric 1, tag 0
    May 16 20:54:18.698: RIP: sending v2 update to 224.0.0.9 via FastEthernet0/0 (192.168.100.60)
    May 16 20:54:18.698: RIP: build update entries
    May 16 20:54:18.698: 192.168.100.192/26 via 0.0.0.0, metric 1, tag 0
    May 16 20:54:43.727: RIP: sending v2 update to 224.0.0.9 via Serial0/0 (192.168.100.200)
    May 16 20:54:43.727: RIP: build update entries
    May 16 20:54:43.727: 192.168.100.0/26 via 0.0.0.0, metric 1, tag 0
    May 16 20:54:48.447: RIP: sending v2 update to 224.0.0.9 via FastEthernet0/0 (192.168.100.60)
    May 16 20:54:48.447: RIP: build update entries
    May 16 20:54:48.447: 192.168.100.192/26 via 0.0.0.0, metric 1, tag 0
    May 16 20:55:12.554: RIP: sending v2 update to 224.0.0.9 via Serial0/0 (192.168.100.200)
    May 16 20:55:12.554: RIP: build update entries
    May 16 20:55:12.554: 192.168.100.0/26 via 0.0.0.0, metric 1, tag 0
    May 16 20:55:15.551: RIP: sending v2 update to 224.0.0.9 via FastEthernet0/0 (192.168.100.60)
    May 16 20:55:15.551: RIP: build update entries
    May 16 20:55:15.551: 192.168.100.192/26 via 0.0.0.0, metric 1, tag 0
    May 16 20:55:41.746: RIP: sending v2 update to 224.0.0.9 via Serial0/0 (192.168.100.200)
    May 16 20:55:41.746: RIP: build update entries
    May 16 20:55:41.746: 192.168.100.0/26 via 0.0.0.0, metric 1, tag 0
    May 16 20:55:43.729: RIP: sending v2 update to 224.0.0.9 via FastEthernet0/0 (192.168.100.60)
    May 16 20:55:43.729: RIP: build update entries
    May 16 20:55:43.729: 192.168.100.192/26 via 0.0.0.0, metric 1, tag 0
    May 16 20:56:09.804: RIP: sending v2 update to 224.0.0.9 via Serial0/0 (192.168.100.200)
    May 16 20:56:09.804: RIP: build update entries
    May 16 20:56:09.804: 192.168.100.0/26 via 0.0.0.0, metric 1, tag 0
    May 16 20:56:13.474: RIP: sending v2 update to 224.0.0.9 via FastEthernet0/0 (192.168.100.60)
    May 16 20:56:13.474: RIP: build update entries
    May 16 20:56:13.474: 192.168.100.192/26 via 0.0.0.0, metric 1, tag 0
    May 16 20:56:36.640: RIP: sending v2 update to 224.0.0.9 via Serial0/0 (192.168.100.200)
    May 16 20:56:36.640: RIP: build update entries
    May 16 20:56:36.640: 192.168.100.0/26 via 0.0.0.0, metric 1, tag 0
    May 16 20:56:43.034: RIP: sending v2 update to 224.0.0.9 via FastEthernet0/0 (192.168.100.60)
    May 16 20:56:43.034: RIP: build update entries
    May 16 20:56:43.034: 192.168.100.192/26 via 0.0.0.0, metric 1, tag 0
    May 16 20:57:05.331: RIP: sending v2 update to 224.0.0.9 via Serial0/0 (192.168.100.200)

    The above is from 1760

    1721#debug ip rip
    RIP protocol debugging is on
    IvanR2_1721#terminal monitor
    IvanR2_1721#
    000370: May 16 21:02:55.690 UTC: RIP: received v2 update from 192.168.100.200 on
    Serial0
    000371: May 16 21:02:55.690 UTC: 192.168.100.0/26 via 0.0.0.0 in 1 hops
    000372: May 16 21:03:12.482 UTC: RIP: sending v2 update to 224.0.0.9 via Serial0
    (192.168.100.199)
    000373: May 16 21:03:12.482 UTC: RIP: build update entries - suppressing null up
    date
    000374: May 16 21:03:21.950 UTC: RIP: received v2 update from 192.168.100.200 on
    Serial0
    000375: May 16 21:03:21.950 UTC: 192.168.100.0/26 via 0.0.0.0 in 1 hops
    000376: May 16 21:03:38.018 UTC: RIP: sending v2 update to 224.0.0.9 via Serial0
    (192.168.100.199)
    000377: May 16 21:03:38.018 UTC: RIP: build update entries - suppressing null up
    date
    000378: May 16 21:03:51.802 UTC: RIP: received v2 update from 192.168.100.200 on
    Serial0
    000379: May 16 21:03:51.802 UTC: 192.168.100.0/26 via 0.0.0.0 in 1 hops

    This from 1721.
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    NetworkVeteranNetworkVeteran Member Posts: 2,338 ■■■■■■■■□□
    That is what I expected. Your 1721 is in fact not sending any updates. Now, I encourage you to look again at your 1721's RIP configuration and database, so you will understand why it has nothing interesting to send.
    biggish wrote: »
    1721#debug ip rip
    RIP protocol debugging is on
    IvanR2_1721#terminal monitor
    IvanR2_1721#
    000370: May 16 21:02:55.690 UTC: RIP: received v2 update from 192.168.100.200 on
    Serial0
    000371: May 16 21:02:55.690 UTC: 192.168.100.0/26 via 0.0.0.0 in 1 hops
    000372: May 16 21:03:12.482 UTC: RIP: sending v2 update to 224.0.0.9 via Serial0
    (192.168.100.199)
    000373: May 16 21:03:12.482 UTC: RIP: build update entries - suppressing null up
    date
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    biggishbiggish Member Posts: 29 ■□□□□□□□□□
    Thanks for that.
    I changed the cable, and everything is working fine now

    Thanks
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