We are monitoring gre tunnels between our core Juniper SRX Junos firewall and ISP, problem is that -even if the router on the other end is down, tunnel still shows green and up.describe more detail when see the interface status… its always up … but when we go in deep and show interface detail ..its show Gre keepalives adjacency state which show the real status i.e. Down or Up, Screen shot attached of NMS and the configuration for your ready reference.
Please guide further.
DR-WAN-RTR-A> show interfaces terse | match gr-
gr-0/0/0 up up
gr-0/0/0.0 up up inet 172.31.0.XX/30
gr-0/0/0.1 up up inet 172.31.0.XX/30
{master}
RTR-A> show interfaces gr-0/0/0.0 detail
Logical interface gr-0/0/0.0 (Index 401) (SNMP ifIndex 636) (Generation 228)
Flags: Up Point-To-Point SNMP-Traps 0x0 IP-Header 172.31.0.121:172.31.0.122:47:df:64:0000000000000007 Encapsulation: GRE-NULL
Gre keepalives configured: On, Gre keepalives adjacency state: up
Traffic statistics:
Input bytes : 254200311977
Output bytes : 193909078145
Input packets: 1576686792
Output packets: 880040711
Local statistics:
Input bytes : 258920888
Output bytes : 539360136
Input packets: 4608673
Output packets: 6734033
Transit statistics:
Input bytes : 253941391089 121064 bps
Output bytes : 193369718009 86872 bps
Input packets: 1572078119 66 pps
Output packets: 873306678 52 pps
Protocol inet, MTU: 1476, Generation: 287, Route table: 7
Flags: Sendbcast-pkt-to-re
Addresses, Flags: Is-Preferred Is-Primary
Destination: 172.31.0.XX/30, Local: 172.31.0.XX, Broadcast: 172.31.0.XX, Generation: 248
{master}
-RTR-A> show interfaces gr-0/0/0.1 detail
Logical interface gr-0/0/0.1 (Index 400) (SNMP ifIndex 637) (Generation 229)
Flags: Up Point-To-Point SNMP-Traps 0x0 IP-Header 172.31.0.137:172.31.0.138:47:df:64:0000000000000007 Encapsulation: GRE-NULL
Gre keepalives configured: On, Gre keepalives adjacency state: up
Traffic statistics:
Input bytes : 1951865462
Output bytes : 2215152952
Input packets: 9453720
Output packets: 8966679
Local statistics:
Input bytes : 5690860
Output bytes : 8190988
Input packets: 101615
Output packets: 102384
Transit statistics:
Input bytes : 1946174602 0 bps
Output bytes : 2206961964 0 bps
Input packets: 9352105 0 pps
Output packets: 8864295 0 pps
Protocol inet, MTU: 1476, Generation: 289, Route table: 7
Flags: Sendbcast-pkt-to-re
Addresses, Flags: Is-Preferred Is-Primary
Destination: 172.31.0.XX/30, Local: 172.31.0.XX, Broadcast: 172.31.0.XX, Generation: 294
{master}