09-27-2008 12:13 PM - edited 03-06-2019 01:38 AM
What is the function and purpose of configuring OSPF characteristics under 2 vlan interface in an HSRP set up (OSPF timers, MD5 mssage digest key, etc), but not allowing the vlan interfaces to establish an adjacency with each other? The vlan interfaces are not exchanging Hellos -- passive interfaces.
See config:
ROUTER 1:
!
interface Vlan523
ip address 19.82.110.130 255.255.255.192
ip access-group Virus_LAN_PIM in
ip helper-address 19.91.56.19
no ip redirects
ip pim sparse-dense-mode
ip cgmp
ip ospf message-digest-key 1 md5 0 december96
ip ospf hello-interval 5
ip ospf dead-interval 15
logging event link-status
load-interval 30
arp timeout 300
standby 100 ip 19.82.110.129
standby 100 timers 1 3
standby 100 priority 115
standby 100 preempt delay minimum 15
standby 100 track Serial2/0/0:0 20
service-policy input EdgeMark2
no shutdown
!
router ospf 521
log-adjacency-changes
auto-cost reference-bandwidth 10000
area 200 authentication message-digest
area 200 nssa no-summary
passive-interface default
no passive-interface Serial2/0/0:0
no passive-interface Port-channel37
network 19.82.110.130 0.0.0.0 area 200
==================================================================================
ROUTER 2:
!
interface Vlan523
ip address 19.82.110.131 255.255.255.192
ip access-group Virus_LAN_PIM in
ip helper-address 19.91.56.19
no ip redirects
ip pim sparse-dense-mode
ip cgmp
ip ospf message-digest-key 1 md5 0 december96
ip ospf hello-interval 5
ip ospf dead-interval 15
logging event link-status
load-interval 30
arp timeout 300
standby 100 ip 19.82.110.129
standby 100 timers 1 3
standby 100 priority 115
standby 100 preempt delay minimum 15
standby 100 track Serial2/0/0:0 20
service-policy input EdgeMark2
no shutdown
!
router ospf 521
log-adjacency-changes
auto-cost reference-bandwidth 10000
area 200 authentication message-digest
area 200 nssa no-summary
passive-interface default
no passive-interface Serial2/0/0:0
no passive-interface Port-channel37
network 19.82.110.131 0.0.0.0 area 200
There are NO OSPF adjacencies established between the vlan interfaces on both routers. The interfaces are 'passived-out.' So why all the OSPF interface-level configs on the vlan interfaces?
Thanks
Solved! Go to Solution.
09-27-2008 05:07 PM
Victor
You are correct that with the VLAN interfaces being set passive that configuring the OSPF parameters on the interface is not changing any behaviors. Without knowing a bit more about the environment it is hard to say for sure. But my guess is that there is a standard interface config for this environment, that the standard config uses these parameters, and that the VLAN interfaces were configured with them to conform to the standard.
I would also note that it may be wise to configure the VLAN interfaces with these parameters, especially if I am correct and this represents some standard in configuration. Today the interface is passive. But what if at some future time someone makes them non-passive? Would they remember at that time to add the standard parameters to the interface?
HTH
Ric
09-27-2008 05:07 PM
Victor
You are correct that with the VLAN interfaces being set passive that configuring the OSPF parameters on the interface is not changing any behaviors. Without knowing a bit more about the environment it is hard to say for sure. But my guess is that there is a standard interface config for this environment, that the standard config uses these parameters, and that the VLAN interfaces were configured with them to conform to the standard.
I would also note that it may be wise to configure the VLAN interfaces with these parameters, especially if I am correct and this represents some standard in configuration. Today the interface is passive. But what if at some future time someone makes them non-passive? Would they remember at that time to add the standard parameters to the interface?
HTH
Ric
09-27-2008 05:36 PM
Hey, Rick:
How you doin', bud?
Yes, I agree with your assessment.
I just posted this question to do a sanity check on my thinking. Was ondering if I was issing something....
The operations prsonnel at this client use a configuration tool that automatically generates a script when certain infomation is inputted into. So, I imagine tht they just allow this configuration to remain on the vlan interfaces for uniformity's sake and for future use, perhaps.
Thanks for the info.
Victor
09-28-2008 04:16 AM
Victor
Sanity checks are a good thing :)
I am glad that you agree that my theory seems to fit the situation at this client. Thanks for the rating.
HTH
Rick
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