SG uses password CISCO for OSPF authentication? Do you know where it comes from? Or it's just arbitrarily chosen?
Arbitrarily selected for this case!
Good luck with your studies!
Okay. I thought I was missing something.
Is it necessary to specifiy a password? It appears as though a null key is used. The task didn't specify one, so I didn't use one. My verification output is the same as the SG with no key configured on either side:
Rack8R6#sh ip ospf int f0/1.26
Neighbor Count is 1, Adjacent neighbor count is 1
Adjacent with neighbor 184.108.40.206 (Backup Designated Router)
Suppress hello for 0 neighbor(s)
Simple password authentication enabled
When I configure a key on R6, this follows:
(No Key on R2)
*Jan 5 15:41:36.848: OSPF: Rcv pkt from 220.127.116.11, FastEthernet0/0.26 : Mismatch Authentication Key - Clear Text
("CISCO" key on R6)
*Jan 5 16:09:13.520: OSPF: Rcv pkt from 18.104.22.168, FastEthernet0/1.26 : Mismatch Authentication Key - Clear Text
I enabled simple password authentication on the interfaces without specifying an authentication-key on either end, and the neighbor relationship authenticated and came up. Does OSPF use a null key or something in these situations?
interface FastEthernet0/0.26 encapsulation dot1Q 26 ip address 22.214.171.124 255.255.255.0 no ip proxy-arp ip pim sparse-dense-mode ip multicast helper-map broadcast 126.96.36.199 105 ip ospf authentication glbp 1 ip 188.8.131.52 glbp 1 preemptend
Rack1R2#sh ip ospf int f0/0.26FastEthernet0/0.26 is up, line protocol is up Internet Address 184.108.40.206/24, Area 0 Process ID 1, Router ID 220.127.116.11, Network Type BROADCAST, Cost: 1 Transmit Delay is 1 sec, State DR, Priority 1 Designated Router (ID) 18.104.22.168, Interface address 22.214.171.124 Backup Designated router (ID) 126.96.36.199, Interface address 188.8.131.52 Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5 oob-resync timeout 40 Hello due in 00:00:09 Supports Link-local Signaling (LLS) Index 3/3, flood queue length 0 Next 0x0(0)/0x0(0) Last flood scan length is 4, maximum is 16 Last flood scan time is 0 msec, maximum is 4 msec Neighbor Count is 1, Adjacent neighbor count is 1 Adjacent with neighbor 184.108.40.206 (Backup Designated Router) Suppress hello for 0 neighbor(s) Simple password authentication enabled
Does OSPF use a null key or something in these situations?
Yes. According to the output of Wireshark below, OSPF uses simplepassword authentication along with a null password as mentioned in the Auth Data field.
Open Shortest Path First
OSPF Version: 2
Message Type: Hello Packet (1)
Packet Length: 44
Source OSPF Router: 220.127.116.11 (18.104.22.168)
Area ID: 0.0.0.0 (Backbone)
Packet Checksum: 0xe495 [correct]
Auth Type: Simple password
Auth Data: <------------------- Null value
OSPF Hello Packet
OSPF LLS Data Block
Just my 2 cents.