09-22-2023
09:51 PM
- last edited on
09-25-2023
01:47 AM
by
Translator
Hello everyone,
So, I'm having issues with OSPF. I had it working, but after I logged out of the packet tracer, it decided it did not work anymore. It keeps getting stuck in the exstart/dr state. I don't know if this could be a packet tracer issue or if I'm missing something important; however, it was working the night before, and I did save it, but now I don't have communication between the multilayer switch and the router.
Neighbor ID Pri State Dead Time Address Interface
10.210.61.1 1 EXSTART/DR 00:00:38 10.210.61.2 GigabitEthernet0/0
Here is my config for my router
Building configuration...
Current configuration : 1400 bytes
!
version 15.1
no service timestamps log datetime msec
no service timestamps debug datetime msec
service password xxx
!
hostname Router
!
!
!
enable secret xxx
!
!
!
!
!
aaa new-model
!
aaa authentication login default local group tacacs+
!
!
!
!
!
!
!
ip cef
no ipv6 cef
!
!
!
username testuser secret xxx
!
!
license udi pid CISCO1941/K9 sn xxx
!
!
!
!
!
!
!
!
!
!
!
spanning-tree mode pvst
!
!
!
!
!
!
interface GigabitEthernet0/0
ip address 10.210.61.1 255.255.255.192
ip ospf 1 area 0
duplex auto
speed auto
!
interface GigabitEthernet0/1
no ip address
duplex auto
speed auto
!
interface GigabitEthernet0/1.10
encapsulation dot1Q 10
no ip address
shutdown
!
interface Vlan1
no ip address
shutdown
!
router ospf 1
router-id 10.210.61.1
log-adjacency-changes
network 10.210.61.192 0.0.0.63 area 0
network 10.210.61.128 0.0.0.63 area 0
network 10.210.61.64 0.0.0.63 area 0
!
ip classless
config for multi-layer switch
no service timestamps log datetime msec
no service timestamps debug datetime msec
no service password xxx
!
hostname Switch
!
!
!
!
ip dhcp pool vlan10
network 10.210.61.64 255.255.255.192
default-router 10.210.61.65
ip dhcp pool vlan20
network 10.210.61.128 255.255.255.192
default-router 10.210.61.129
ip dhcp pool vlan30
network 10.210.61.192 255.255.255.192
default-router 10.210.61.193
!
!
!
no ip cef
ip routing
!
no ipv6 cef
!
!
!
!
!
!
!
!
!
!
!
!
!
!
spanning-tree mode pvst
!
!
!
!
!
!
interface GigabitEthernet1/0/1
switchport mode trunk
!
interface GigabitEthernet1/0/2
switchport mode trunk
!
interface GigabitEthernet1/0/3
no switchport
ip address 10.210.61.2 255.255.255.192
ip ospf 1 area 0
duplex auto
speed auto
!
interface GigabitEthernet1/0/4
!
interface GigabitEthernet1/0/5
!
interface GigabitEthernet1/0/6
!
interface GigabitEthernet1/0/7
!
interface GigabitEthernet1/0/8
!
interface GigabitEthernet1/0/9
!
interface GigabitEthernet1/0/10
!
interface GigabitEthernet1/0/11
!
interface GigabitEthernet1/0/12
!
interface GigabitEthernet1/0/13
!
interface GigabitEthernet1/0/14
!
interface GigabitEthernet1/0/15
!
interface GigabitEthernet1/0/16
!
interface GigabitEthernet1/0/17
!
interface GigabitEthernet1/0/18
!
interface GigabitEthernet1/0/19
!
interface GigabitEthernet1/0/20
!
interface GigabitEthernet1/0/21
!
interface GigabitEthernet1/0/22
!
interface GigabitEthernet1/0/23
!
interface GigabitEthernet1/0/24
!
interface GigabitEthernet1/1/1
!
interface GigabitEthernet1/1/2
!
interface GigabitEthernet1/1/3
!
interface GigabitEthernet1/1/4
!
interface Vlan1
no ip address
shutdown
!
interface Vlan10
mac-address 00d0.5885.2301
ip address 10.210.61.65 255.255.255.192
!
interface Vlan20
mac-address 00d0.5885.2302
ip address 10.210.61.129 255.255.255.192
!
interface Vlan30
mac-address 00d0.5885.2303
ip address 10.210.61.193 255.255.255.192
!
router ospf 1
router-id 10.210.61.1
log-adjacency-changes
network 10.210.61.192 0.0.0.63 area 0
network 10.210.61.128 0.0.0.63 area 0
network 10.210.61.64 0.0.0.63 area 0
!
ip classless
!
ip flow-export version 9
!
Solved! Go to Solution.
09-22-2023
11:49 PM
- last edited on
09-25-2023
01:12 AM
by
Translator
Hello @BoomBastic1234626283,
On you multi layer Switch modify the
router-id
on the OSPF process. Router and this Sw has got the same
router-id.
Instead of
router-id 10.210.61.1
Configure this:
router-id 10.210.61.2
09-23-2023
12:39 AM
- last edited on
09-25-2023
01:35 AM
by
Translator
That's it...both router and Multilayer switch are having same
router-id: 10.210.61.1
router-id
is unique...two devices should not have the same
router-id
. Chage
router-id
in any one of the device (router or Multi-laryer switch)
that solve's the problem....
Thanks
09-23-2023
05:19 AM
- last edited on
09-25-2023
01:18 AM
by
Translator
Glad to read your problem was identified.
If you're learning networking, I have several suggestions.
Change default pvst to rapid pvst.
Change link between switch and router to /30 or /31. For OSPF, configure it as
p2p. (/30 or /31 not required for OSPF p2p.)
Don't use an interface IP for RID unless it's a loopback. If you use loopback for RID consider adding it to OSPF.
Using the (newer) interface OSPF statement negates the need to use an OSPF network statement to pick up interface's IP network; believe you could use it on your SVIs.
Your router doesn't need subinterfaces nor VLAN OSPF network statements.
OSPF network statements do not advertise networks, they pick up matching interface IP addresses for interface's IP network inclusion. I.e. they work like an ACL ACE matching interface IP.
For example for:
ip address 10.210.61.65 255.255.255.192
Besides
network 10.210.61.64 0.0.0.63 area 0
The following would also do the same:
network 10.210.61.65 0.0.0.0 area 0
(The prior is the equivalent of interface statement "ip ospf 1 area 0".)
network 10.210.61.0 0.0.0.255 area 0
network 0.0.0.0 255.255.255.255 area 0
The last two network statements, especially the last, might match multiple interfaces. Either of those would match all your interfaces on your switch.
09-22-2023
11:49 PM
- last edited on
09-25-2023
01:12 AM
by
Translator
Hello @BoomBastic1234626283,
On you multi layer Switch modify the
router-id
on the OSPF process. Router and this Sw has got the same
router-id.
Instead of
router-id 10.210.61.1
Configure this:
router-id 10.210.61.2
09-23-2023
12:39 AM
- last edited on
09-25-2023
01:35 AM
by
Translator
That's it...both router and Multilayer switch are having same
router-id: 10.210.61.1
router-id
is unique...two devices should not have the same
router-id
. Chage
router-id
in any one of the device (router or Multi-laryer switch)
that solve's the problem....
Thanks
09-23-2023
12:49 AM
- last edited on
09-25-2023
01:14 AM
by
Translator
Hello,
post the (zipped) Packet Tracer project
(.pkt) file...
09-23-2023
05:19 AM
- last edited on
09-25-2023
01:18 AM
by
Translator
Glad to read your problem was identified.
If you're learning networking, I have several suggestions.
Change default pvst to rapid pvst.
Change link between switch and router to /30 or /31. For OSPF, configure it as
p2p. (/30 or /31 not required for OSPF p2p.)
Don't use an interface IP for RID unless it's a loopback. If you use loopback for RID consider adding it to OSPF.
Using the (newer) interface OSPF statement negates the need to use an OSPF network statement to pick up interface's IP network; believe you could use it on your SVIs.
Your router doesn't need subinterfaces nor VLAN OSPF network statements.
OSPF network statements do not advertise networks, they pick up matching interface IP addresses for interface's IP network inclusion. I.e. they work like an ACL ACE matching interface IP.
For example for:
ip address 10.210.61.65 255.255.255.192
Besides
network 10.210.61.64 0.0.0.63 area 0
The following would also do the same:
network 10.210.61.65 0.0.0.0 area 0
(The prior is the equivalent of interface statement "ip ospf 1 area 0".)
network 10.210.61.0 0.0.0.255 area 0
network 0.0.0.0 255.255.255.255 area 0
The last two network statements, especially the last, might match multiple interfaces. Either of those would match all your interfaces on your switch.
09-23-2023
05:31 AM
- last edited on
09-25-2023
01:33 AM
by
Translator
You use dhcp pool and ospf
When you close one of l3 device have
router ID
and then when you open again the dhcp assign different IP make other devices have same IP and use same
router ID
. That what I think if I am right.
Clear
ip ospf
process and check if it solve issue then it sure it
router ID
issue
09-23-2023 06:13 AM
Huh?
Could you further explain how DHCP relates/influences the hard coded, same, OSPF RID (10.210.61.1) on both the router and L3 switch?
Perhaps you have mind the defined pools don't explicitly exclude gateway IP being used?
If you do, though, the adjacency issue is on a network without a DHCP pool.
So, cannot see a direct impact but it would be a good suggestion to mention explicitly excluding gateway IPs.
Another possibly good suggestion, which I intended to add in my prior reply, but then forgot, would be to make the SVIs passive interfaces.
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