Table of contents
Lesson 9 - CCNA Fast Track (June, 2025). We left off at page 163. It ends at the top of pg 186.
0. CCNA Exam Questions
- There are alternative ways to hash/encrypt passwords where
0= Unencrypted secret,5= MDS Hashed secret,8PBKDF2 Hashed Secret,9SCRYPT Hashed secret
13 SSH : Secure SHell
13.3 Setting up hostname and domain names !
- Recall, this is our topology:
- Method 1: Please perform the following on R1
conf t username user1 secret pass1 line vty 0 4 login local transport input ssh end - Let’s break it down a bit…
username user1 secret pass1= username and passwordline vty 0 4vty: Multiple entries into Router user mode, referring to diagram pt. 2 from page 18login local: login w/ local user info (i.e. user1 pass1)transport input ssh: limits only ssh to enter the 5 vtysm and limits virtual terminals to accept SSH connections only
- Remarks:
- Cisco IOS ssh servers requires username based auth, hence need username-password pair (i.e. user1, pass1)
- Method 2: Bash or encrypt the password
- Here are the possible methods to setup your secrets
Router1(config)# username user1 secret ? 0 specifies a UNENCRYPTED secret will follow 5 specifies a MDS Hashed secret will follow 8 specifies a PBKDF2 Hashed Secret will follow 9 specifies a SCRYPT Hashed secret will follow - On R2, privilage mode
ssh -l user1 192.168.1.1(i.e. Trying to access R1 from R2 via ssh) and enter the password and it should work :D
14. IPv6
14.1 Overview
- IPv6 = latest verion of IP (= Internet Protocol)
- IPv6 is 128 bits long (vs IPv4 which is 32 bits long)
- 128 buts is more than enough for global unique IP addresses (since number of IPv6 address is 2^128 = 340 undecillion addresses)
14.2 IPv6 Addressing Representation
- IPv6 has 32 hexadecimal digits
- Recall our calcip.com 4 hexes * 8 groups = 32 hex digits (note 1 hex = 4 bit)
Lab 5: NAT, SSH, ACL
Simulation
Simulation 42
Topology:
Tasks:
- Overall layout, all physical cabling is in place. R2 and R3 are inaccessible. Config OSPF routing for the network and ensure R1 has joined area 0 WITHOUT using network statements!
- Task 1:
- Need to configure OSPF on R1 iwth process ID and router ID only as the following…
- Using process ID 33
- Use e0/1 IP as the router ID
- Solution:
- on R1:
en sh run - This will help get the router ID and all the ip address of the connected interfaces!
- Returns the following output
interface Loopback 0 ip address 10.11.11.11 255.255.255.255 ! interface Ethernet0/0 ip address 10.0.22.1 255.255.255.252 duplex auto ! interface Ethernet0/1 ip address 10.0.33.1 255.255.255.248 duplex auto ! interface Ethernet0/2 no ip address duplex auto !- This means that the IP address for the int e0/1 is
10.0.33.1. So we should configure ospf on that IP ! Note:ospf 33the process ID is then 33 - Continuing on R1
en config t router ospf 33 router-id 10.0.33.1 end copy run startNote: page 155 is for OSPF unification and page 159 is for clearing OSPF process
- on R1:
- Need to configure OSPF on R1 iwth process ID and router ID only as the following…
- Task 2: Need to configure 2 things…
- One, configure R1 to establish neighbor adjacencies with R2 and R3. DO NOT USE the network statements under the OSPF process
- Two, Config R1 to ALWAYS be the DR for area 0!
- Solution:
- on R1
en config t int e0/0 ip ospf 33 area 0 ip ospf priority 255 int e0/1 ip ospf 33 area 0 ip ospf priority 255 end copy run start
- on R1
- Explanation: the
255is merely to make R1 the DR always since it is the highest priority (default is 1). Hence R2 and R3 will be BDR and DROTHER respectively.255is the max priority value!
Simulation 31
- Topology:
Device Interface IP Address R1 Loopback 0 10.1.1.1/32 R2 Loopback 0 10.2.2.2/32 R3 Loopback 0 10.3.3.3/32 SW101 Loopback 0 10.101.1.1/32 SW101 VLAN 101 10.101.101.101/24 - Tasks:
- Task 1: Refer to the diagram. Configure OSPF area 0 with process ID 1 on R1, R2 and R3 and SW101. Use a single command under the OSPD process to achieve this.
- Solution: Perform all the following on R1, R2, R3 and SW101
en config t router ospf 1 network 10.0.0.0 0.255.255.255 area 0 end copy run start- Explanation: Note that all IP starts with 10.x.x.x, hence we can use the wildcard mask of 0.255.255.255 to off set it. Hence
router ospf 1+network 10.0.0.0 0.255.255.255 area 0
- Task 2: Configure SW 101 so that it’s always gonna be the DR for the VLAN 101 network. Note, there should be no BDR. Two things to be careful about.
- First, don’t use the neighbor command under the OSPF process to achieve this. (i.e.
ospfhas been banned) - Second, no config changes can be performed on SW 101 (no touching SW 101)
- Solution: Perform on R1, R2 and R3 using priority, with ints facing SW101
- For R1
en config t int e0/2 ip ospf priority 0 end copy run start - For R2
en config t int e0/1 ip ospf priority 0 end copy run start - For R3
en config t int e0/0 ip ospf priority 0 end copy run start
- For R1
- Explanation:
- Doing
ip ospf priority 0on all R1, R2 and R3 facing SW101 will ensure SW101 is always the DR since it has the highest priority (default is 1). Therefore eliminating the need to configure DR and BDR.pirority 0means it cannot be elected as DR or BDR = giving up on DR and BDR chances. - Had neighbor command been allowed, we could have configured SW101 as DR directly using neighbor command under OSPF process.
- Recall in page 155 where we can do things like
sh ip ospf int g0/0orsh ip ospf neighborto verify the DR and BDR status. For refernce click here
- Doing
- First, don’t use the neighbor command under the OSPF process to achieve this. (i.e.
- Task 1: Refer to the diagram. Configure OSPF area 0 with process ID 1 on R1, R2 and R3 and SW101. Use a single command under the OSPD process to achieve this.