Windows Error codes

  When you have enter a site and it shows site unable with an error code. You can make out that the problem is by referring to these error codes.

 
400 - Bad Request - You probably typed in a URL wrong, the server has no clue what you're looking for, or you aren't allowed to have access. Usually, it's a matter of the URL being typing in wrong. Maybe you mixed upper and lowercase letters or something.

401 - Unauthorized Request - you tried to get to something on the web server you're not allowed to play with. In other words, you ain't on the party list.

403 - Forbidden - You can't access the page. You may not have access (it may require a password), or it may be blocked from your domain.

404 - Not Found - The page you were trying to look at was not found on the server. This is probably the most common error you'll come across. What has probably happened is that the web page you were going to has been removed or re-named.

500 - Internal error - Usually caused by a CGI error. You fill out a form, but the script used to process it is not working properly.

503 - Service Unavailable - The server may be overloaded, down, or have other similar problems. Try later

Examining Network Address Translation (NAT)

Topology Diagram

Download Packet Tracer File

Objectives 

• Examine NAT processes as traffic traverses a NAT border router.

Background / Preparation

In this activity, you will use Packet Tracer Simulation mode to examine the contents of the IP header as traffic crosses the NAT border router.

Step 1: Prepare the network for Simulation mode.

Verify that the network is ready to send and receive traffic. All the link lights should be green. If some link lights are still amber, you can switch between Simulation and Realtime mode several times to force the lights to turn green faster. Switch to Simulation mode before going to the next step.

Step 2: Send an HTTP request from an inside host to an outside web server.

a. Click Customer PC. Click the Desktop tab and then Web Browser. In the URL field, type the web address for the ISP server (www.ispserver.com). Make sure that you are in Simulation mode, and then click Go.

b. In the event list, notice that Customer PC queues a DNS request and sends out an ARP request. You can view the contents of the ARP request by either clicking on the packet in the topology or clicking on the packet color under Info in the Event List window.

c. In the PDU Information at Device: Customer PC window, which IP address is Customer PC attempting to find a MAC address for?

d. In the Event List window, click Capture/Forward twice. Which device answers the ARP request from Customer PC? Which MAC address is placed inside the ARP reply?

e. In the Event List window, click Capture/Forward twice. Customer PC accepts the ARP replay and then builds another packet. What is the protocol for this new packet? If you click Outbound PDU Details for this packet, you can see the details of the protocol.

f. In the Event List window, click Capture/Forward twice. Click the packet at the www.customerserver.com server. Then click the Outbound PDU Details tab. Scroll down to the bottom to see the Application Layer data. What is the IP address for the ISP server?

g. In the Event List window, click Capture/Forward twice. Customer PC now formulates another ARP request. Why?

h. In the Event List window, click Capture/Forward 10 times until Customer PC formulates an HTTP request packet. Customer PC finally has enough information to request a web page from the ISP server.

i. In the Event List window, click Capture/Forward three times. Click the packet at Customer Router to examine the contents. Customer Router is a NAT border router. What is the inside local address and the inside global address for Customer PC?

j. In the Event List window, click Capture/Forward seven times until the HTTP reply reaches Customer Router. Examine the contents of the HTTP reply and notice that the inside local and global addresses have changed again as the packet is forwarded on to Customer PC.

Step 3: Send an HTTP request from an outside host to an inside web server.

Customer Server provides web services to the public (outside addresses) through the domain name www.customerserver.com. Follow a process similar to Step 2 to observe an HTTP request on ISP Workstation.

a. Click ISP Workstation. Click the Desktop tab, and then Web Browser. In the URL field, type the Customer Server web address (www.customerserver.com). Make sure that you are in Simulation mode, and then click Go.

b. You can either click Auto Capture/Play or Capture/Forward to step through each stage of the process. The same ARP and DNS processes occur before the ISP Workstation can formulate an HTTP request.

c. When the HTTP request arrives at Customer Router, check the packet contents. What is the inside local address? What is the inside global address?

Exploring Different LAN Switch Options

Download Packet Tracer File

Objectives

•    Determine the cable types to use to connect all devices to the switch.
•    Add appropriate modules to switches and routers.
•    Connect the devices to the switch using the appropriate cable types.

Background / Preparation

The results of a site survey for an ISP customer indicate that the customer needs to upgrade the LAN to include a new standalone switch. The network has an existing router (Router0) and a Linksys 300N router. It is necessary to determine which interfaces are needed on the new switch to provide connectivity to the router, the Linksys device, and the customer PCs. The customer wants to use copper cabling.
Note: Links created with the switch may take a minute to change from amber to green. Switch between Simulation mode and Realtime mode to speed up this process.

Step 1: Determine the required connectivity options.

a. Click Router0. Using the information in the Physical Device View window on the Physical tab, determine what type of interface is available on the router to connect to the new switch.

Hint: Place the mouse pointer on the interface to display the interface type. Click on the interface type to display a description of the interface.
b. Which interface is available on the router to connect to the new switch? What type of cable is required?

c. Click the Linksys 300N. Using the picture on the Physical tab, determine what type of cable is necessary to connect to the new switch.

d. Which interface is available on the Linksys 300N to connect to the new switch? What type of cable is required?

Step 2: Configure the new switch with the required options.

a. Click Switch0.
b. On the Physical tab, explore each switch module available under the Modules option.
c. Choose the appropriate interfaces to connect to Router0 and the Linksys 300N router.
d. Choose the appropriate interfaces to connect to the existing PCs.
e. Power down the switch using the power button in the Physical Device View window on the Physical tab.
f. Choose the appropriate modules for the switch. Add the four necessary interfaces to the switch.
g. Power up the switch using the power button shown in the Physical Device View window on the Physical tab.
h. Click the Config tab. Select each interface and ensure that the On box is checked.

Step 3: Connect the router to the switch.

a. Using the appropriate cable, connect the router port to the first available switch port. Click the Config tab on the router. Select the interface and ensure that the On box is checked. 

 

b. Verify connectivity. A green light appears on each end of the link if the cabling is correct.

Step 4: Connect the Linksys 300N to the switch.

a. Using the appropriate cable, connect the Linksys 300N to the second available port on the new switch.
b. Verify connectivity. A green light appears on each end of the link if the cabling is correct.

Step 5: Connect the PCs to the switch.

a. Using the appropriate cable, connect the existing PCs to the new switch.
b. Verify connectivity. A green light appears on each end of the links if the cabling is correct.
c. Click the Check Results button at the bottom of this instruction window to check your work.

CCNA Activities - Interpreting Ping and Traceroute Output

Topology Diagram

 Download Topology File

Objectives

• Distinguish the difference between successful and unsuccessful ping attempts.
• Distinguish the difference between successful and unsuccessful traceroute attempts.

Background / Preparation
In this activity, you will test end-to-end connectivity using ping and traceroute. At the end of this activity, you will be able to distinguish the difference between successful and unsuccessful ping and traceroute attempts.
Note: Before beginning this activity, make sure that the network is converged. To converge the network quickly, switch between Simulation mode and Real-time mode until all the link lights turn green.

Step 1: Test connectivity using ping from a host computer and a router.
a. Click N-Host, click the Desktop tab, and then click Command Prompt. From the Command Prompt window, ping the Cisco server at www.cisco.com.
Packet Tracer PC Command Line 1.0
PC>ping www.cisco.com
Pinging 64.100.1.185 with 32 bytes of data:

Request timed out.
Reply from 64.100.1.185: bytes=32 time=185ms TTL=123
Reply from 64.100.1.185: bytes=32 time=281ms TTL=123
Reply from 64.100.1.185: bytes=32 time=287ms TTL=123

Ping statistics for 64.100.1.185:
    Packets: Sent = 4, Received = 3, Lost = 1 (25% loss),
Approximate round trip times in milli-seconds:
    Minimum = 185ms, Maximum = 287ms, Average = 251ms

PC>

b. From the output, you can see that N-Host was able to obtain an IP address for the Cisco server. The IP address was obtained using (DNS). Also notice that the first ping failed. This failure is most likely due to lack of ARP convergence between the source and destination. If you repeat the ping, you will notice that all pings succeed.

c. From the Command Prompt window on N-Host, ping E-Host at 192.168.4.10. The pings fail. If you do not want to wait for all four unsuccessful ping attempts, press Ctrl+C to abort the command, as shown below.

PC>ping 192.168.4.10
Pinging 192.168.4.10 with 32 bytes of data:
Request timed out.
Request timed out.

Ping statistics for 192.168.4.10:
Packets: Sent = 3, Received = 0, Lost = 3 (100% loss),
Control-C
^C
PC>

d. Click the N-Branch router, and then click the CLI tab. Press Enter to get the router prompt. From the router prompt, pings the Cisco server at www.cisco.com.

N-Branch>ping www.cisco.com
Translating "www.cisco.com"...domain server (64.100.1.242)
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 64.100.1.185, timeout is 2 seconds:
.!!!!
Success rate is 80 percent (4/5), round-trip min/avg/max = 210/211/213 ms

N-Branch>

e. As you can see, the ping output on a router is different from a PC host. Notice that the N-Branch router resolved the domain name to the same IP address that N-Host used to send its pings. Also notice that the first ping fails, which is indicated by a period (.), and that the next four pings succeed, as shown with an exclamation point (!).

f. From the CLI tab on N-Branch, ping E-Host at 192.168.4.10. Again, the pings fail. To not wait for all the failures,
press Ctrl+C.
N-Branch>ping 192.168.4.10

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 192.168.4.10, timeout is 2 seconds: ...
Success rate is 0 percent (0/4)

N-Branch>

Step 2: Test connectivity using traceroute from a host computer and a router.

a. Click N-Host, click the Desktop tab, and then click Command Prompt. From the Command Prompt window, trace the route to the Cisco server at www.cisco.com.

PC>tracert www.cisco.com

Tracing route to 64.100.1.185 over a maximum of 30 hops:

  1   92 ms     77 ms     86 ms     192.168.1.1
  2   91 ms     164 ms    84 ms     64.100.1.101
  3   135 ms    168 ms    151 ms    64.100.1.6
  4   185 ms    261 ms    161 ms    64.100.1.34
  5   257 ms    280 ms    224 ms    64.100.1.62
  6   310 ms    375 ms    298 ms    64.100.1.185

Trace complete.

PC>

b. The above output shows that you can successfully trace a route all the way to the Cisco server at 64.100.1.185. Each hop in the path is a router responding three times to trace messages from N-Host. The trace continues until the destination for the trace (64.100.1.185) responds three times.

c. From the Command Prompt window on N-Host, trace a route to E-Host at 192.168.4.10. The trace fails, but notice that the tracert command traces up to 30 hops. If you do not want to wait for all 30 attempts to time out, press Ctrl+C.

PC>tracert 192.168.4.10

Tracing route to 192.168.4.10 over a maximum of 30 hops:

  1   103 ms    45 ms     91 ms     192.168.1.1
  2   56 ms     110 ms    125 ms    64.100.1.101
  3   174 ms    195 ms    134 ms    64.100.1.6
  4   246 ms    183 ms    179 ms    64.100.1.34
  5   217 ms    285 ms    226 ms    64.100.1.62
  6   246 ms    276 ms    245 ms    64.100.1.154
  7   *         *         *         Request timed out.
  8   *         *         *         Request timed out.
  9   *         *         *         Request timed out.
  10  

Control-C
^C
PC>

The tracert command can be helpful in finding the potential source of a problem. The last device to respond was 64.100.1.154, so you would start troubleshooting by determining which device is configured with the IP address 64.100.1.154. The source of the problem might not be that device, but the trace has given you a starting point, whereas a ping simply tells you that the destination is either reachable or unreachable.

d. Click the N-Branch router, and then click the CLI tab. Press Enter to get the router prompt. From the router prompt, trace the route to the Cisco server at www.cisco.com.

N-Branch>traceroute www.cisco.com
Translating "www.cisco.com"...domain server (64.100.1.242)
Type escape sequence to abort.
Tracing the route to 64.100.1.185

  1   64.100.1.101    60 msec   32 msec   59 msec  
  2   64.100.1.6      98 msec   65 msec   65 msec  
  3   64.100.1.34     138 msec  147 msec  147 msec 
  4   64.100.1.62     189 msec  148 msec  145 msec 
  5   64.100.1.185    219 msec  229 msec  293 msec 
N-Branch>

As you can see, traceroute output on a router is very similar to the output on a PC host. The only difference is that on a PC host, the IP address is listed after the three millisecond outputs.

e. From the CLI tab on N-Branch, trace the route to E-Host at 192.168.4.10. The trace fails at the same IP address as it failed when tracing from N-Host. Again, you can use Ctrl+C to abort the command.

N-Branch>traceroute 192.168.4.10
Type escape sequence to abort.
Tracing the route to 192.168.4.10

  1   64.100.1.101    41 msec   19 msec   32 msec  
  2   64.100.1.6      33 msec   92 msec   117 msec 
  3   64.100.1.34     98 msec   102 msec  102 msec 
  4   64.100.1.62     166 msec  172 msec  156 msec 
  5   64.100.1.154    157 msec  223 msec  240 msec 
  6   *     *     *    
  7   *     *     *    
  8   *     *     *    
  9  
N-Branch>
Step 3: Practice the ping and trace route commands.

Throughout this course, you will often use ping and traceroute to test connectivity and troubleshoot problems. To practice these commands, ping and trace from W-Host and S-Host to any other destination in the network. You can also ping and trace from N-Branch to other locations.