A lab that worked on Wednesday, didn't work on Thursday, or on Friday but worked on another platform.
I started working on DMVPN with OSPF as the Routing protocol, and that too didn't work in one platform but did work on another.
The Video:
Day 5
!Hub int tun 0 ip add 10.123.234.1 255.255.255.0 tunnel source Gi0/0 tunnel mode gre multipoint no shut !Spoke int tun 0 ip add 10.123.234.2 255.255.255.0 tunnel source Gi0/0 tunnel destination 10.123.234.1 no shut ! Broke R2#sho int tun 0 Tunnel0 is up, line protocol is down Hardware is Tunnel Internet address is 10.123.234.2/24 MTU 17916 bytes, BW 100 Kbit/sec, DLY 50000 usec, reliability 255/255, txload 1/255, rxload 1/255 Encapsulation TUNNEL, loopback not set Keepalive not set Tunnel linestate evaluation down - no output interface Tunnel source 172.17.100.2 (GigabitEthernet0/0), destination 10.123.234.1 Tunnel Subblocks: src-track: Tunnel0 source tracking subblock associated with GigabitEthernet0/0 Set of tunnels with source GigabitEthernet0/0, 1 member (includes iterators), on interface <OK> Tunnel protocol/transport GRE/IP Key disabled, sequencing disabled Checksumming of packets disabled Tunnel TTL 255, Fast tunneling enabled Tunnel transport MTU 1476 bytes Tunnel transmit bandwidth 8000 (kbps) Tunnel receive bandwidth 8000 (kbps) Last input never, output never, output hang never Lesson Learned: I made the error of incorrectly defining the tunnel destination. I defined it as the remote tunnel interface when actually I needed to use the public NBMA address. Fixed:
R2#sho int tun 0
Tunnel0 is up, line protocol is up
Hardware is Tunnel
Internet address is 10.123.234.2/24
MTU 17916 bytes, BW 100 Kbit/sec, DLY 50000 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation TUNNEL, loopback not set
Keepalive not set
Tunnel linestate evaluation up
Tunnel source 172.17.100.2 (GigabitEthernet0/0), destination 172.17.100.1
Tunnel Subblocks:
src-track:
Tunnel0 source tracking subblock associated with GigabitEthernet0/0
Set of tunnels with source GigabitEthernet0/0, 1 member (includes iterators), on interface <OK>
Tunnel protocol/transport GRE/IP
Key disabled, sequencing disabled
Checksumming of packets disabled
Tunnel TTL 255, Fast tunneling enabled
Tunnel transport MTU 1476 bytes
Tunnel transmit bandwidth 8000 (kbps)
Tunnel receive bandwidth 8000 (kbps)
Last input never, output never, output hang never
Explanation: The tunnel interface linestate stays down until it has a valid exit interface and route to the remote tunnel destination.
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In the output below you can see "Keepalive not set". Tunnel keepalives are not set by default. You can configure keepalives under the tunnel interface. You can do this be specifying just the keyword "keepalive" and press enter. This will give you the default value of keepalives sent every 10 seconds and will retry 3 times before considering the tunnel down. Conversely you can specify the keepalive values( example 5 seconds) the retry values can also be set but if they are excluded will default to 3 retries.
R4#sho int tun 0
Tunnel0 is up, line protocol is up
Hardware is Tunnel
Internet address is 10.123.234.4/24
MTU 17916 bytes, BW 100 Kbit/sec, DLY 50000 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation TUNNEL, loopback not set
Keepalive not set
[ ... output omitted ... ]
Keepalive with default values
R3(config-if)#keepalive ?
<0-32767> Keepalive period (default 10 seconds)
<cr>
R3(config-if)#keepalive
R3(config-if)#
R3(config-if)#do sho int tun 0
Tunnel0 is up, line protocol is up
Hardware is Tunnel
Internet address is 10.123.234.3/24
MTU 17916 bytes, BW 100 Kbit/sec, DLY 50000 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation TUNNEL, loopback not set
Keepalive set (10 sec), retries 3
[ ... output omitted ... ]
Keepalive with defined values
R4(config)#int tun 0R4(config-if)#keepalive 5 R4(config-if)#end R4# R4#sho int tun 0 Tunnel0 is up, line protocol is up Hardware is Tunnel Internet address is 10.123.234.4/24 MTU 17916 bytes, BW 100 Kbit/sec, DLY 50000 usec, reliability 255/255, txload 1/255, rxload 1/255 Encapsulation TUNNEL, loopback not set Keepalive set (5 sec), retries 3
[ ... output omitted ... ]
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