Course
notes: CISCO Exam 640-801
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Contents Page 3:
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Introduction to IP Addressing |
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Subnetting |
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Configuring IP |
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CDP and Auto Install |
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Backing up and upgrading IOS |
Course
notes taken by Craig Ellis (MCP)
IP Addressing:
When configuring TCP/IP to communicate from a HOST to the router the administrator must always configure:
IP Address - i.e. 192.107.10.2
Subnet mask - i.e. 255.255.255.0
Default gateway - 192.107.10.1 (or use a DHCP server to configure this information automatically)
If you are connecting your network onto the Internet then you will need to contact the InterNIC or your local ISP (Internet Service Provider) for a valid IP address range.
If you are not going to use the Internet on your network, then any IP addressing scheme would be valid.
IP Addressing Classes:
The IP address range has 5 different classes A to E, also required will be the subnet mask address:
|
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IP Address |
Subnet Mask |
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Class A |
1 to 126 |
255.0.0.0 |
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Class B |
128 to 191 |
255.255.0.0 |
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Class C |
192 to 223 |
255.255.255.0 |
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Class D |
224 to 247 |
Multicast / Broadcast |
|
Class E |
248 to 254 |
Reserved |
IP Address 127.0.0.1 is a Loopback address, used to test TCP/IP communications to the host (network card)
MAC Addresses:
IP address to network interface card definitions use the ARP protocol which doesn’t travel through a router, send to a defined gateway address if not on a local network.
This allows you to borrow host bits from an IP subnet mask and make more networks out of the IP address.
i.e. to get a class C subnet of 25 subnets you would borrow the 1st 5 bits of the host class C, IP address 192.0.0.0 255.255.255.0
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128 |
64 |
32 |
16 |
8 |
4 |
2 |
1 |
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/ |
/ |
/ |
/ |
/ |
= 31 subnets (-1 = 30 can't have all bits on as this would be a broadcast)
Next move these bits over to the left hand side:
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128 |
64 |
32 |
16 |
8 |
4 |
2 |
1 |
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/ |
/ |
/ |
/ |
/ |
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|
This leaves a subnet mask = 248 (full address 192.0.0.0 255.255.255.248)
Also leaving 6 hosts on each network (7 -1 hosts as cant have all bits on as this would be a broadcast)
NB All bits as 1 will be a broadcast, all bits as 0 equals this network only.
Example 2: For a 224 subnet mask address the valid host ranges per subnet would be:
|
SUBNET |
HOSTS |
Broadcast Address |
IP bits used in a Byte |
|
32 |
33 to 62 |
63 |
00100000 |
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64 |
65 to 94 |
95 |
01000000 |
|
96 |
97 to 126 |
127 |
01100000 |
|
128 |
129 to 158 |
159 |
10000000 |
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160 |
161 to 190 |
191 |
10100000 |
|
192 |
193 to 223 |
224 |
11000000 |
Login to privileged mode on the router then:
CONFIG T
INT e0 (access Ethernet configuration mode for port 0)
IP ADDRESS 131.107.10.1 255.255.255.0 (IP address and subnet mask)
NO SHUTDOWN (enabled the Ethernet port)
END (Finishes and exits set-up)
SHOW RUN (running configuration) will display and confirm that the Ethernet port is UP
Also try the same with the serial port:
CONFIG T
INT s0 (access serial port 0)
IP ADDRESS 131.107.11.2 255.255.255.0
NO SHUTDOWN (enabled the serial port)
END
Don’t forget to configure your HOST PC using TCP/IP assigning an IP address, for example
Host 131.107.10.2
Subnet mask 255.255.255.0
Gateway 131.107.10.1
Then reboot your PC to enable the change.
On the router type: SHOW CONTROLLERS S 0 (this shows if the router is providing DCE = clock)
CONFIG T
INT s0
CLOCK RATE 56000 (or whatever rate your want to communicate at)
BANDWIDTH 56 (set at 56k, but not required for IP)
SHOW RUN (check running configuration)
Access your other router:
You should have another router in your LAN set-up with the IP address of 131.107.11.1 255.255.255.0
From your 1st router type: TELNET 131.107.11.1
This will allow access to your 2nd router on your LAN, a password maybe required, remember LINE VTY CON 0 set-up.
To exit from telnet access press CTRL SHIFT 6 X (exits router but doesn't close telnet session)
From the 1st router type:
SHOW SESSIONS (check which sessions are open on your router)
RESUME (restarts session connection)
EXIT (quits session)
SHOW PROTOCOLS (will display what protocols are running on the router)
i.e. ethernet0 is up, line protocol is up
Internet address is 131.107.10.1/24 (24 bits used in a subnet mask)
SHOW IP INT (displays all protocols running IP)
SHOW IP ROUTE (displays directly connected interfaces i.e. e0 and s0 also C=directly connected)
Cisco Discovery Protocol is
broadcast every 60 seconds by Cisco routers to find if there are any other
Cisco routers on the network.
Holddown is set to 180 seconds, used
if a router stops communicating and keeps data in router file.
Type SHOW CDP ? (Displays
Entry/Interface/Neighbour)
SHOW CDP ENTRY (show all neighbours
with CDP protocol running)
SHOW CDP NEIGHBOR (show capabilities
of local Cisco router)
SHOW CDP TRAFFIC (show CDP packets
sent across the network)
SHOW CDP (check CDP times of broadcast
and holddown - these can be amended)
Auto Install
Uses CDP to configure routers over
the network
BOOTP (boot protocol request for an
IP address)
HOSTNAME (is resolved through the
network.config file - reverse lookup)
Config. Information is obtained from
the HOSTNAME.CONFIG file
(Needs a DNS server set-up on the
network for hostnames)
NB. Use CDP to build a topology map
of all Cisco routers on your network by telnet into each router and checking
the CDP router configuration.
Backing up IOS to TFTP server
From ROUTER#
COPY FLASH TFTP (*.BIN image to network server)
Copying TFTP IOS to Flash
ROUTER#
Copy TFTP FLASH
(Confirm router non-functionality when reloading data)
(Confirm erasure of flash memory)
Saving router configuration info
ROUTER#
COPY RUNNING-CONFIG STARTUP-CONFIG (copies the running config. to NVRAM memory)
COPY RUNNING-CONFIG TFTP (copy to TFTP server)
(TFTP server name or address required)
(File name also required)
Erase configuration information
ROUTER#
ERASE STARTUP-CONFIG
or WRITE ERASE (this will clear the running config. - make sure you have a backup copy)
Selection
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