OSPF not working

[Alex Hall]

I have two routers connected with serial interfaces and to begin with I was unable to ping either router, anyway I want to configure OSPF 100 with the routers on area 0 the current configs are

Router 1:

Building configuration...

Current configuration : 1077 bytes

!

version 12.4

no service timestamps log datetime msec

no service timestamps debug datetime msec

no service password-encryption

!

hostname HQ

!

!

!

enable secret 5 $1$mERr$Kf7LJHoCqrlN7frh/vXzO1

enable password ttf1234

!

!

!

!

!

!

ip cef

no ipv6 cef

!

!

!

username ttfadmin privilege 15 secret 5 $1$mERr$sGPHml/Zec.vL6mmhKJAd0

!

!

!

!

!

!

!

!

no ip domain-lookup

!

!

spanning-tree mode pvst

!

!

!

!

!

!

interface FastEthernet0/0

no ip address

duplex auto

speed auto

shutdown

!

interface FastEthernet0/1

no ip address

duplex auto

speed auto

shutdown

!

interface Serial0/0/0

ip address 10.10.10.2 255.255.255.252

ip ospf 100 area 0

!

interface Serial0/0/1

ip address 10.20.20.2 255.255.255.252

ip ospf 100 area 0

clock rate 64000

!

interface Vlan1

no ip address

shutdown

!

router ospf 100

log-adjacency-changes

network 10.10.10.0 0.0.0.3 area 0

network 10.20.20.0 0.0.0.3 area 0

neighbor 10.10.10.1

neighbor 10.20.20.1

!

ip classless

!

ip flow-export version 9

!

!

!

!

!

!

!

!

line con 0

!

line aux 0

!

line vty 0 4

password ttf12345

login local

!

!

!

end

Router 2:

Building configuration...

Current configuration : 1044 bytes

!

version 12.4

no service timestamps log datetime msec

no service timestamps debug datetime msec

no service password-encryption

!

hostname Adelaide

!

!

!

enable secret 5 $1$mERr$KZJUS7CY9GPgCalBziSwO1

enable password ttf123456

!

!

!

!

!

!

ip cef

no ipv6 cef

!

!

!

username ttfadmin privilege 15 secret 5 $1$mERr$sGPHml/Zec.vL6mmhKJAd0

!

!

!

!

!

!

!

!

!

!

spanning-tree mode pvst

!

!

!

!

!

!

interface FastEthernet0/0

no ip address

duplex auto

speed auto

shutdown

!

interface FastEthernet0/1

ip address 192.168.1.1 255.255.255.0

ip ospf 100 area 0

duplex auto

speed auto

!

interface Serial0/0/0

ip address 10.10.10.1 255.255.255.252

ip ospf 100 area 0

!

interface Serial0/0/1

no ip address

clock rate 2000000

shutdown

!

interface Vlan1

no ip address

shutdown

!

router ospf 100

log-adjacency-changes

network 192.168.1.0 0.0.0.255 area 0

network 10.10.10.0 0.0.0.3 area 0

neighbor 10.20.20.2

!

ip classless

!

ip flow-export version 9

!

!

!

!

!

!

!

!

line con 0

!

line aux 0

!

line vty 0 4

password ttf1234567

login

!

!

!

end

------------------------

Router 1 also has another router it's connected to but it's just a mirror of router 2, I'm not sure what I've done wrong, can someone provide some help, please excuse the ignorance I'm new to this.

Thanks in advance.

[Mark Malone]

Hi
are the serial interfaces up/up ? show interface sx/x , you dont need the neighbor commands or shouldn't require these either under the interfaces ip ospf 100 area 0 as you have set the subnets under the process , have you set the clock rate on the DCE side too i dont see it under either 10 range network interface ?

most connections are ethernet now if your practicing this for a LAB , serial is nearly gone too slow nowaday


https://www.cisco.com/c/en/us/support/docs/ip/open-shortest-path-first-ospf/13687-15.html#conf1

[Alex Hall]

Hey mate both interfaces are up yes

[Georg Pauwen]

Hello,

I was labbing this up in GNS3 while Mark provided the answer, so my apologies if I am being redundant. Either way, the below should be sufficient to establish a FULL adjacency:

Router 1:

interface Serial0/0/0
ip address 10.10.10.2 255.255.255.252
clock rate 64000

!

router ospf 100
network 10.10.10.0 0.0.0.3 area 0

Router 2:

interface Serial0/0/0
ip address 10.10.10.1 255.255.255.252
!
router ospf 100
network 10.10.10.0 0.0.0.3 area 0

[Alex Hall]

Hi mate I reconfigured the routers to match yours and I'm still not getting a ping, I'm really stuff for this, I'll include the updated configs below. Cheers.

Router 1:

Building configuration...

Current configuration : 995 bytes

!

version 12.4

no service timestamps log datetime msec

no service timestamps debug datetime msec

no service password-encryption

!

hostname HQ

!

!

!

enable secret 5 $1$mERr$Kf7LJHoCqrlN7frh/vXzO1

enable password ttf1234

!

!

!

!

!

!

ip cef

no ipv6 cef

!

!

!

username ttfadmin privilege 15 secret 5 $1$mERr$sGPHml/Zec.vL6mmhKJAd0

!

!

!

!

!

!

!

!

no ip domain-lookup

!

!

spanning-tree mode pvst

!

!

!

!

!

!

interface FastEthernet0/0

no ip address

duplex auto

speed auto

shutdown

!

interface FastEthernet0/1

no ip address

duplex auto

speed auto

shutdown

!

interface Serial0/0/0

ip address 10.10.10.2 255.255.255.252

!

interface Serial0/0/1

ip address 10.20.20.2 255.255.255.252

clock rate 64000

!

interface Vlan1

no ip address

shutdown

!

router ospf 100

log-adjacency-changes

network 10.10.10.0 0.0.0.3 area 0

network 10.20.20.0 0.0.0.3 area 0

!

ip classless

!

ip flow-export version 9

!

!

!

!

!

!

!

!

line con 0

!

line aux 0

!

line vty 0 4

password ttf12345

login local

!

!

!

end

Router 2:

Building configuration...

Current configuration : 945 bytes

!

version 12.4

no service timestamps log datetime msec

no service timestamps debug datetime msec

no service password-encryption

!

hostname Adelaide

!

!

!

enable secret 5 $1$mERr$KZJUS7CY9GPgCalBziSwO1

enable password ttf123456

!

!

!

!

!

!

ip cef

no ipv6 cef

!

!

!

username ttfadmin privilege 15 secret 5 $1$mERr$sGPHml/Zec.vL6mmhKJAd0

!

!

!

!

!

!

!

!

!

!

spanning-tree mode pvst

!

!

!

!

!

!

interface FastEthernet0/0

no ip address

duplex auto

speed auto

shutdown

!

interface FastEthernet0/1

ip address 192.168.1.1 255.255.255.0

duplex auto

speed auto

!

interface Serial0/0/0

ip address 10.10.10.1 255.255.255.252

!

interface Serial0/0/1

no ip address

clock rate 2000000

shutdown

!

interface Vlan1

no ip address

shutdown

!

router ospf 100

log-adjacency-changes

network 10.10.10.0 0.0.0.3 area 0

!

ip classless

!

ip flow-export version 9

!

!

!

!

!

!

!

!

line con 0

!

line aux 0

!

line vty 0 4

password ttf1234567

login

!

!

!

end

Adelaide#show run

Building configuration...

Current configuration : 945 bytes

!

version 12.4

no service timestamps log datetime msec

no service timestamps debug datetime msec

no service password-encryption

!

hostname Adelaide

!

!

!

enable secret 5 $1$mERr$KZJUS7CY9GPgCalBziSwO1

enable password ttf123456

!

!

!

!

!

!

ip cef

no ipv6 cef

!

!

!

username ttfadmin privilege 15 secret 5 $1$mERr$sGPHml/Zec.vL6mmhKJAd0

!

!

!

!

!

!

!

!

!

!

spanning-tree mode pvst

!

!

!

!

!

!

interface FastEthernet0/0

no ip address

duplex auto

speed auto

shutdown

!

interface FastEthernet0/1

ip address 192.168.1.1 255.255.255.0

duplex auto

speed auto

!

interface Serial0/0/0

ip address 10.10.10.1 255.255.255.252

!

interface Serial0/0/1

no ip address

clock rate 2000000

shutdown

!

interface Vlan1

no ip address

shutdown

!

router ospf 100

log-adjacency-changes

network 10.10.10.0 0.0.0.3 area 0

!

ip classless

!

ip flow-export version 9

!

!

!

!

!

!

!

!

line con 0

!

line aux 0

!

line vty 0 4

password ttf1234567

login

!

!

!

end

[Mark Malone · Accepted solution]

Your still missing the clock rate command thats whats required on DCE side

interface Serial0/0/0
ip address 10.10.10.2 255.255.255.252
clock rate 64000

[Alex Hall]

So when i tried to set clock rate on router 1 serial0/0/1 it let's me but for router 2 serial0/0/0 it doesn't allow me saying "This command applies only to DCE interfaces

[paul driver]

Hello

---

@Alex Hall @ wrote
 have two routers connected with serial interfaces and to begin with I was unable to ping either router, anyway I want to configure OSPF 100 with the routers on area 0

---

you have confirmed if this Is this a GNS lab or physical routers, Are these routers directly connected?

It looks like from your configuration your encapsulation is HLDC is that correct?

show interfaces serial0/0/0 | in up| En

sh controllers serial0/0/0 | in DCE|DTE

[Alex Hall]

This is built in packet tracer

[Richard Burts]

Would you post the output of these commands on both routers.

show ip interface brief

show cdp neighbor

HTH

Rick

[Alex Hall]

Cheers for the reply here you go,

Router 2:
Adelaide#show ip interface brief
Interface IP-Address OK? Method Status Protocol
FastEthernet0/0 unassigned YES unset administratively down down
FastEthernet0/1 192.168.1.1 YES manual up up
Serial0/0/0 10.10.10.1 YES manual up up
Serial0/0/1 unassigned YES unset administratively down down
Vlan1 unassigned YES unset administratively down down
Adelaide#show cdp nei
Adelaide#show cdp neighbors
Capability Codes: R - Router, T - Trans Bridge, B - Source Route Bridge
S - Switch, H - Host, I - IGMP, r - Repeater, P - Phone
Device ID Local Intrfce Holdtme Capability Platform Port ID
S1 Fas 0/1 169 S 2960 Fas 0/1
HQ Ser 0/0/0 152 R C1841 Ser 0/0/1

Router 1:

HQ#show ip interface brief
Interface IP-Address OK? Method Status Protocol
FastEthernet0/0 unassigned YES unset administratively down down
FastEthernet0/1 unassigned YES unset administratively down down
Serial0/0/0 10.10.10.2 YES manual up up
Serial0/0/1 10.20.20.2 YES manual up up
Vlan1 unassigned YES unset administratively down down
HQ#show cdp nei
HQ#show cdp neighbors
Capability Codes: R - Router, T - Trans Bridge, B - Source Route Bridge
S - Switch, H - Host, I - IGMP, r - Repeater, P - Phone
Device ID Local Intrfce Holdtme Capability Platform Port ID
Sydney Ser 0/0/0 146 R C1841 Ser 0/0/1
Adelaide Ser 0/0/1 171 R C1841 Ser 0/0/0

[Richard Burts]

The output of show ip interface brief confirms that both interfaces are up/up

Adelaide#show ip interface brief

Serial0/0/0 10.10.10.1 YES manual up up

HQ#show ip interface brief

Serial0/0/0 10.10.10.2 YES manual up up

And the output of show cdp neighbor confirms that they see each other

Adelaide#show cdp nei

HQ Ser 0/0/0 152 R C1841 Ser 0/0/1

HQ#show cdp nei

Adelaide Ser 0/0/1 171 R C1841 Ser 0/0/0

So it looks like it should work. But if you look carefully you will notice that the connection should be s0/0/0 to s0/0/0

Adelaide#show ip interface brief

Serial0/0/0 10.10.10.1 YES manual up up

HQ#show ip interface brief

Serial0/0/0 10.10.10.2 YES manual up up

But if you look carefully you will notice that the connection is actually s0/0/0 to s0/0/1

Adelaide#show cdp nei

HQ Ser 0/0/0 152 R C1841 Ser 0/0/1

HQ#show cdp nei

Adelaide Ser 0/0/1 171 R C1841 Ser 0/0/0

So the issue is that physically the interfaces are cross connected. This is why you can not ping and why OSPF will not form neighbor relationships.

HTH

Rick

[Alex Hall]

SCC HDLC PARSMETER RAM (at 0x68013C00

[Sebastian Fernandez]

Packet tracer is not a very friendly simulation for serial connectivity. This appears more to be PT issue as oppose to actual configuration.

[Alex Hall]

What would you recommend instead, are there any other simulation programs that I can use as I don't have access to physical routers to test.