Tuesday, March 9, 2021

Nexus 9k pair - Two default routes configured?

Hello,

Ran across this recently on a core switch pair of Nexus 9ks configured by a previous vendor. Symptoms where odd ingress speed issues via a Meraki VPN link. Egress is fine so I started to look at the configs and do some testing from each switch.

I do not have current diagrams for this network but its fairly simple -

2 Nexus 93180ex-yc's in a VPC pair NX-OS 7.3

2 Wan connected L2 trunked from 2 4431 ISRs

Meraki MX 100 as the last hop to ether the VPN or out to the net

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10.8.120.254 should be the gateway while 10.8.120.1 is the hsrp VIP for VLAN 120

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I can not remove 10.8.120.1 via no ip route

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Also one switch can ping 8.8.8.8 while the other can't, however, they can both ping 1.1.1.1

VPC Peer-Link config -

sw1# sh run | sec vpc feature vpc vpc domain 150 peer-keepalive destination 172.16.150.2 source 172.16.150.1 peer-gateway layer3 peer-router auto-recovery ip arp synchronize vpc peer-link interface port-channel1 description ***VPC Peer Link*** switchport mode trunk spanning-tree port type network vpc peer-link 

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Here's what I see in the routing table -

sw1# sh ip route IP Route Table for VRF "default" '*' denotes best ucast next-hop '**' denotes best mcast next-hop '[x/y]' denotes [preference/metric] '%<string>' in via output denotes VRF <string> 0.0.0.0/0, ubest/mbest: 2/0 *via 10.8.120.1, [1/0], 1y9w, static *via 10.8.120.254, [1/0], 1y9w, static 10.8.99.0/24, ubest/mbest: 1/0, attached *via 10.8.99.250, Vlan99, [0/0], 1y9w, direct 10.8.99.1/32, ubest/mbest: 1/0, attached *via 10.8.99.1, Vlan99, [0/0], 1y9w, hsrp 10.8.99.250/32, ubest/mbest: 1/0, attached *via 10.8.99.250, Vlan99, [0/0], 1y9w, local 10.8.100.0/23, ubest/mbest: 1/0, attached *via 10.8.101.250, Vlan100, [0/0], 1y9w, direct 10.8.100.1/32, ubest/mbest: 1/0, attached *via 10.8.100.1, Vlan100, [0/0], 1y9w, hsrp 10.8.101.250/32, ubest/mbest: 1/0, attached *via 10.8.101.250, Vlan100, [0/0], 1y9w, local 10.8.102.0/23, ubest/mbest: 1/0, attached *via 10.8.103.250, Vlan102, [0/0], 1y9w, direct 10.8.102.1/32, ubest/mbest: 1/0, attached *via 10.8.102.1, Vlan102, [0/0], 1y9w, hsrp 10.8.103.250/32, ubest/mbest: 1/0, attached *via 10.8.103.250, Vlan102, [0/0], 1y9w, local 10.8.104.0/23, ubest/mbest: 1/0, attached *via 10.8.105.250, Vlan104, [0/0], 1y9w, direct 10.8.104.1/32, ubest/mbest: 1/0, attached *via 10.8.104.1, Vlan104, [0/0], 1y9w, hsrp 10.8.105.250/32, ubest/mbest: 1/0, attached *via 10.8.105.250, Vlan104, [0/0], 1y9w, local 10.8.106.0/23, ubest/mbest: 1/0, attached *via 10.8.107.250, Vlan106, [0/0], 1y9w, direct 10.8.106.1/32, ubest/mbest: 1/0, attached *via 10.8.106.1, Vlan106, [0/0], 1y9w, hsrp 10.8.107.250/32, ubest/mbest: 1/0, attached *via 10.8.107.250, Vlan106, [0/0], 1y9w, local 10.8.108.0/23, ubest/mbest: 1/0, attached *via 10.8.109.250, Vlan108, [0/0], 1y9w, direct 10.8.108.1/32, ubest/mbest: 1/0, attached *via 10.8.108.1, Vlan108, [0/0], 1y9w, hsrp 10.8.109.250/32, ubest/mbest: 1/0, attached *via 10.8.109.250, Vlan108, [0/0], 1y9w, local 10.8.110.0/23, ubest/mbest: 1/0, attached *via 10.8.111.250, Vlan110, [0/0], 1y9w, direct 10.8.110.1/32, ubest/mbest: 1/0, attached *via 10.8.110.1, Vlan110, [0/0], 1y9w, hsrp 10.8.111.250/32, ubest/mbest: 1/0, attached *via 10.8.111.250, Vlan110, [0/0], 1y9w, local 10.8.112.0/23, ubest/mbest: 1/0, attached *via 10.8.113.250, Vlan112, [0/0], 1y9w, direct 10.8.112.1/32, ubest/mbest: 1/0, attached *via 10.8.112.1, Vlan112, [0/0], 1y9w, hsrp 10.8.113.250/32, ubest/mbest: 1/0, attached *via 10.8.113.250, Vlan112, [0/0], 1y9w, local 10.8.118.0/24, ubest/mbest: 1/0, attached *via 10.8.118.250, Vlan118, [0/0], 1y9w, direct 10.8.118.1/32, ubest/mbest: 1/0, attached *via 10.8.118.1, Vlan118, [0/0], 1y9w, hsrp 10.8.118.250/32, ubest/mbest: 1/0, attached *via 10.8.118.250, Vlan118, [0/0], 1y9w, local 10.8.119.0/24, ubest/mbest: 1/0, attached *via 10.8.119.250, Vlan119, [0/0], 1y9w, direct 10.8.119.1/32, ubest/mbest: 1/0, attached *via 10.8.119.1, Vlan119, [0/0], 1y9w, hsrp 10.8.119.250/32, ubest/mbest: 1/0, attached *via 10.8.119.250, Vlan119, [0/0], 1y9w, local 10.8.120.0/24, ubest/mbest: 1/0, attached *via 10.8.120.250, Vlan120, [0/0], 1y9w, direct 10.8.120.1/32, ubest/mbest: 1/0, attached *via 10.8.120.1, Vlan120, [0/0], 1y9w, hsrp 10.8.120.250/32, ubest/mbest: 1/0, attached *via 10.8.120.250, Vlan120, [0/0], 1y9w, local 10.8.121.0/24, ubest/mbest: 1/0, attached *via 10.8.121.250, Vlan121, [0/0], 1y9w, direct 10.8.121.1/32, ubest/mbest: 1/0, attached *via 10.8.121.1, Vlan121, [0/0], 1y9w, hsrp 10.8.121.250/32, ubest/mbest: 1/0, attached *via 10.8.121.250, Vlan121, [0/0], 1y9w, local 10.8.122.0/24, ubest/mbest: 1/0, attached *via 10.8.122.250, Vlan122, [0/0], 1y9w, direct 10.8.122.1/32, ubest/mbest: 1/0, attached *via 10.8.122.1, Vlan122, [0/0], 1y9w, hsrp 10.8.122.250/32, ubest/mbest: 1/0, attached *via 10.8.122.250, Vlan122, [0/0], 1y9w, local 10.8.123.0/24, ubest/mbest: 1/0, attached *via 10.8.123.250, Vlan123, [0/0], 1y9w, direct 10.8.123.1/32, ubest/mbest: 1/0, attached *via 10.8.123.1, Vlan123, [0/0], 1y9w, hsrp 10.8.123.250/32, ubest/mbest: 1/0, attached *via 10.8.123.250, Vlan123, [0/0], 1y9w, local 10.8.124.0/24, ubest/mbest: 1/0, attached *via 10.8.124.250, Vlan124, [0/0], 1y9w, direct 10.8.124.1/32, ubest/mbest: 1/0, attached *via 10.8.124.1, Vlan124, [0/0], 1y9w, hsrp 10.8.124.250/32, ubest/mbest: 1/0, attached *via 10.8.124.250, Vlan124, [0/0], 1y9w, local 10.8.125.0/24, ubest/mbest: 1/0, attached *via 10.8.125.250, Vlan125, [0/0], 1y9w, direct 10.8.125.1/32, ubest/mbest: 1/0, attached *via 10.8.125.1, Vlan125, [0/0], 1y9w, hsrp 10.8.125.250/32, ubest/mbest: 1/0, attached *via 10.8.125.250, Vlan125, [0/0], 1y9w, local 10.8.126.0/23, ubest/mbest: 1/0, attached *via 10.8.127.250, Vlan126, [0/0], 1y9w, direct 10.8.126.1/32, ubest/mbest: 1/0, attached *via 10.8.126.1, Vlan126, [0/0], 16:33:32, hsrp 10.8.127.250/32, ubest/mbest: 1/0, attached *via 10.8.127.250, Vlan126, [0/0], 1y9w, local 10.155.12.40/32, ubest/mbest: 1/0 *via 10.8.120.254, [1/0], 1y9w, static 10.155.12.55/32, ubest/mbest: 1/0 

SW2 is identical

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During some testing yesterday I decided to shut one of the SVI's associated with the WiFi to test routing behavior with just 1 int. Doing that on the Primary caused total disruption in traffic which was unexpected.

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I believe this was caused by a copy/paste of the config from a set of 4500x's as the mgmt vrf had its own GW. I also believe ripping off the config, correcting, and tftping the startup config back might be the only solution here but wanted to get some more opinions before I call TAC.



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