Some Questions on OSPF 5

[Tony414]

Hello,
I am going to implement OSPF on our network. Not a big network, a total of only 5 1700 routers. Can anywone give me some common mistakes that people might make when implementing it? If there is evey any. Can someone give me a quick example? Lets just say I have 2 routers. Router A and Router B. One thing I'm not sure of is the area setting. Thanks in advance for the help.

Tony

 

[Tony414]

I have it on 4 of the 5 routers...

 

[jneiberger]

Can you post an example of your OSPF configs?

Also, just for reference, can you go to one of your Town Hall routers and do a "show ip ospf adj"? I just want to see if your router's OSPF processes are speaking to one another.

 

[jneiberger]

Oops...the show command should be "show ip ospf neighbor". If you want to debug neighbor relationships, you use the adjacency keyword.

 

[Tony414]

Ha! That's ok. Here is the outcome.. Is this worse?

TownHall>sh ip ospf nei

Neighbor ID Pri State Dead Time Address Interface
172.16.51.2 0 FULL/ - 00:00:35 172.16.51.2 Serial0

 

[jneiberger]

Yeah, something isn't working. Each Town Hall router should have three neighbors. Yours only has one. That probably means that something is misconfigured. Can you post the interface configs and OSPF configs from a Town Hall router and its three neighbors?

 

[Tony414]

Here ya go! Sorry for the delay

Townhall

!
version 12.3
service timestamps debug uptime
service timestamps log uptime
service password-encryption
!
hostname TownHall
!
boot system flash flash:c1700-y-mz.123-1a.bin
enable password 7 14051D1E180138663020626771
!
ip subnet-zero
!
!
no ip domain lookup
!
!
!
!
!
interface FastEthernet0
description connected to TownHall LAN
ip address 10.81.0.1 255.255.0.0
speed 100
full-duplex
!
interface Serial0
description connected to HighSchool
ip address 172.16.51.1 255.255.255.252
no ip unreachables
encapsulation ppp
ip route-cache flow
service-module t1 clock source internal
service-module t1 remote-alarm-enable
service-module t1 fdl ansi
!
interface Serial1
description connected to PoliceDept
ip address 172.16.51.5 255.255.255.252
encapsulation ppp
ip route-cache flow
service-module t1 clock source internal
service-module t1 remote-alarm-enable
service-module t1 fdl ansi
!
router ospf 1
log-adjacency-changes
network 172.16.51.1 0.0.0.0 area 0
network 172.16.51.5 0.0.0.0 area 0
default-information originate always
!
ip classless
ip route 0.0.0.0 0.0.0.0 172.16.51.2 permanent
ip route 10.91.0.0 255.255.0.0 172.16.51.6 permanent
ip route 10.101.0.0 255.255.0.0 10.81.0.5 permanent
ip route 10.111.0.0 255.255.0.0 10.81.0.5 permanent
ip route 10.121.0.0 255.255.0.0 10.81.0.6 permanent
ip http server
!
WELCOME TO THE TOWNHALL ROUTER!
!
line con 0
exec-timeout 0 0
password 7 0958411E170D161E075D5679
login
line aux 0
line vty 0 2
password 7 131118050504052627757A60
login
line vty 3 4
login
!
no scheduler allocate
!
end

TownHall2


!
version 12.3
service timestamps debug uptime
service timestamps log uptime
service password-encryption
!
hostname TownHall2
!
boot system flash flash:c1700-y-mz.123-1a.bin
enable password 7 044904131B245E031D1157464058
!
ip subnet-zero
ip rcmd rsh-enable
ip rcmd remote-host tony414 10.81.0.16 tony414 enable
!
!
no ip domain lookup
!
!
!
!
!
interface FastEthernet0
description connected to TownHall LAN
ip address 10.81.0.5 255.255.0.0
speed 100
full-duplex
!
interface Serial0
description connected to PublicWorks
ip address 172.16.51.9 255.255.255.252
encapsulation ppp
no fair-queue
service-module t1 clock source internal
service-module t1 remote-alarm-enable
service-module t1 fdl ansi
!
interface Serial1
description connected to ParkRec
ip address 172.16.51.13 255.255.255.252
encapsulation ppp
service-module t1 clock source internal
service-module t1 remote-alarm-enable
service-module t1 fdl ansi
!
router ospf 1
log-adjacency-changes
network 172.16.51.9 0.0.0.0 area 0
network 172.16.51.13 0.0.0.0 area 0
!
ip classless
ip route 0.0.0.0 0.0.0.0 10.81.0.1 permanent
ip route 10.101.0.0 255.255.0.0 172.16.51.10 permanent
ip route 10.111.0.0 255.255.0.0 172.16.51.14 permanent
ip http server
!
snmp-server community router-public123 RO
snmp-server community router-guilford123 RW
snmp-server location 31 Park St. 2nd Floor Closet
snmp-server contact Tony Santarcangelo,203-453-8466,santat@ci.guilford.ct.us
snmp-server enable traps tty
banner motd Unauthorized use or access will be prosecuted to the fullest extent of the law!

WELCOME TO THE TOWNHALL ROUTER 2 !

!
line con 0
exec-timeout 0 0
password 7 01070913550307032D1E1F5B4A
login
line aux 0
line vty 0 4
password 7 02120B4C050E0E2D401C584B56
login
!
no scheduler allocate
!
end

HighSchool


!
version 12.2
service timestamps debug uptime
service timestamps log uptime
service password-encryption
!
hostname HighSchool
!
enable password 7 06140034584B1B540D0443595F
!
ip subnet-zero
ip rcmd rsh-enable
ip rcmd remote-host tony414 10.81.0.16 tony414
no ip domain-lookup
!
!
!
!
interface FastEthernet0
description connected to HighSchool LAN
ip address 10.0.0.20 255.255.255.0
speed auto
!
interface Serial0
description connected to TownHall
ip address 172.16.51.2 255.255.255.252
encapsulation ppp
service-module t1 clock source internal
service-module t1 remote-alarm-enable
service-module t1 fdl ansi
!
router ospf 1
log-adjacency-changes
network 172.16.51.2 0.0.0.0 area 0
!
ip classless
ip route 0.0.0.0 0.0.0.0 10.0.0.1
ip route 10.81.0.0 255.255.0.0 172.16.51.1 permanent
ip route 10.91.0.0 255.255.0.0 172.16.51.1 permanent
ip route 10.101.0.0 255.255.0.0 172.16.51.1 permanent
ip route 10.111.0.0 255.255.0.0 172.16.51.1 permanent
ip route 10.121.0.0 255.255.0.0 172.16.51.1 permanent
ip http server
!
WELCOME TO THE HIGHSCHOOL-TOWNHALL ROUTER!

!
line con 0
exec-timeout 0 0
password 7 05030F08295F4D01160A1B43595F
login
line aux 0
line vty 0 2
password 7 011B0F03531805072E4342584B56
login
line vty 3 4
login
!
end

PublicWorks

Current configuration : 1271 bytesll
!
version 12.3
snmp
service timestamps debug uptimed123 RW252
service timestamps log uptimep-server location 31 Park St.
service password-encryption source internal
!
hostname PublicWorks
!
boot system flash flash:c1700-y-mz.123-1a.binntarcangelo,203-453-8466,santat@ci.guilford.c
enable password 7 0316541E120A33015E1E485744
service
!o
ip subnet-zeroi
no ip rcmd domain-loo
interface FastEthernet0
description connected to PuplicWorks LAN17
log
ip address 10.101.0.1 255.255.0.0
line vty 0 4
p
speed auto120B4C050E0
!D
interface Serial072.16.51.1 perman
description connected to TownHall2

ip address 172.16.51.10 255.255.255.252
ip route 10.121
encapsulation ppp

TownHall2#
no fair-queuet
service-module t1 remote-alarm-enable
ip

Curren
service-module t1 fdl ansihool#exit
snmp-server community router-public123 RO
snmp-server community router-guilford123 RW
snmp-server contact Tony Santarcangelo,203-453-8466,santat@ci.guilford.ct.us
snmp-server enable traps tty
banner motd ^CCUnauthorized use or access will be prosecuted to the fullest exte
n
t of the law!

WELCOME TO THE PUBLICWORKS ROUTER!^C
!
line con 0
exec-timeout 0 0
password 7 15021C5D5679
login
line aux 0
line vty 0 4
password 7 071F361D1C5A
login
!
no scheduler allocate
!
end

 

[jneiberger]

In your OSPF configs, you'll need to add network statements for all of your subnets, not just the WAN links. Go through and add your LAN interfaces in your configs and let's see if that looks better.

The network statement in OSPF does two things. It specifies which local networks on a router you want to advertise, but it also specifies on which interfaces you want to run OSPF. You need to add the LAN interfaces into your OSPF config in order to advertise them even though you won't be actually running OSPF over most of them.

 

[Tony414]

The PublicWorks one is all messed up. I will post it again.

!
version 12.3
service timestamps debug uptime
service timestamps log uptime
service password-encryption
!
hostname PublicWorks
!
boot system flash flash:c1700-y-mz.123-1a.bin
enable password 7 0316541E120A3301
!
ip subnet-zero
no ip rcmd domain-lookup
!
!
!
!
!
!
!
interface FastEthernet0
description connected to PuplicWorks LAN
ip address 10.101.0.1 255.255.0.0
speed auto
!
interface Serial0
description connected to TownHall2
ip address 172.16.51.10 255.255.255.252
encapsulation ppp
no fair-queue
service-module t1 remote-alarm-enable
service-module t1 fdl ansi
!
router ospf 1
log-adjacency-changes
network 172.16.51.10 0.0.0.0 area 0
!
ip classless
ip route 0.0.0.0 0.0.0.0 172.16.51.9 permanent
ip route 10.81.0.0 255.255.0.0 172.16.51.9 permanent
ip http server
!
WELCOME TO THE PUBLICWORKS ROUTER!^C
!
line con 0
exec-timeout 0 0
password 7 15021C5D5679
login
line aux 0
line vty 0 4
password 7 071F361D1C5A
login
!
no scheduler allocate
!
end

 

[Tony414]

So your saying put in there

10.0.0.0
10.101.0.0 etc...

Should I also be putting in all wans as well?

 

[jneiberger]

Yes. On any given router, add a network statement for every interface on that router.

 

[burtsbees]

Townhall need this
router ospf 1
log-adjacency-changes
network 172.16.51.1 0.0.0.0 area 0
network 172.16.51.5 0.0.0.0 area 0
default-information originate always
changed to this
router ospf 1
log-adjacency-changes
network 172.16.51.0 0.0.0.255 area 0
network 10.81.0.0 0.0.255.255 area 0
default-information originate always

and Townhall2 need this
router ospf 1
log-adjacency-changes
network 172.16.51.9 0.0.0.0 area 0
network 172.16.51.13 0.0.0.0 area 0
changed to this
router ospf 1
log-adjacency-changes
network 172.16.51.0 0.0.0.255 area 0
network 10.81.0.0 0.0.255.255 area 0

and Highschool need this
router ospf 1
log-adjacency-changes
network 172.16.51.2 0.0.0.0 area 0
changed to this
router ospf 1
log-adjacency-changes
network 172.16.51.0 0.0.0.255 area 0
network 10.0.0.0 0.0.0.255 area 0
and finally Public Works needs this
well, the output of the sh run from that one came out screwy...just add the connected interface subnets to ospf 1, area 0.

Burt

 

[burtsbees]

Oh---and the default-info orig al added to each ospf 1...

Burt

 

[Tony414]

Each LAN address, correct? Do I need to be putting in the other Serial addresses in there also, or just the ones that are on that router? Which I believe I did already. Sorry, a little confused. I'm normally not this dumb

 

[jneiberger]

Burt, you only want the default-information originate always to be on the router that you want to originate that information. You definitely do not want all of your routers originating a default route.

 

[jneiberger]

Tony,

On each router, add a network statement for each local IP interface. That will be two or three network statements per router. That includes any LAN or WAN links on that router.

As Burt suggested, you could use a different mask for your network statements to reduce the number of statements required. I just was taught by my networking guru to use a specific network statement for each interface. It just makes troubleshooting easier in the long run. You can do it whichever way you feel like doing it.

 

[Tony414]

This is what I'm stuck on. I have 2 routers on the same lan. Should I be putting in the serial ip's of there counter parts and vise versa?

 

[jneiberger]

No. On any given router, only add network statements for its locally connected networks. As I said before, this will result in two or three network statements per router.

 

[Tony414]

Gotch ya!

 

[Tony414]

All added in. The only thing I wasn't sure on was the 10.0.0.20 route. Is this correct?

router ospf 1
log-adjacency-changes
network 10.0.0.0 0.0.255.255 area 0
network 10.101.0.0 0.0.255.255 area 0
network 10.111.0.0 0.0.255.255 area 0
network 172.16.51.1 0.0.0.0 area 0
network 172.16.51.5 0.0.0.0 area 0
default-information originate always

 

[Tony414]

I just thought of something. Should I be going into the interface and configuring ospf, or is it global?