Network Troubleshooting FAQs

Network Troubleshooting FAQs

 

Question 1

My internet service is out, how can I start troubleshoot?

Steps:

  • Check physical cable connectivity
  • Check IP address released by your DHCP server
  • Unplug and Plug in the cable
  • Trace your default gateway provided by your ISP and see where you end up then inform your ISP in case you reach the gateway and still no internet service.

Question 2

How can I check my internet Speed?

Visit https://www.speedtest.net/ then click “GO”

Question 3

I reach at the firewall when tracing, what should I do?

Steps:

  • Check carefully the rules created
  • Restart the firewall

Question 4

There is a network connection but I can’t browse the internet

Steps:

  • Ping DHCP and DNS servers if they are reachable
  • Check your DHCP server when the cable is tightly connected
  • Check your DNS server when the cable is properly connected

Question 5

I have interconnected manageable switch but unable get internet, what can I do?

Steps:

  • Check internal configurations if the ports are configured to be a trunks or access ports.

Note: Make sure the trunk ports are connected the same and access ports too.

  • Did you configure default gateway on the switch?

Question 6

My wireless access point is slow to connect and accessing to the internet, what should I do?

Steps:

  • Update device firmware
  • Check the number of hosts connected to the device.
  • Restart the device

Question 7

I set up new router in the network but computer connected can’t access the internet

Steps:

  • Check when host can get IP address
  • Check your NAT configurations

Question 8

My Internet is slow, what should I do?

Steps:

  • Connect the cable to the public switch and assign Public IP address to your PC.
  • Visit https://www.speedtest.net/ then click “GO”
  • When subscribed Mbps is below what is shown, contact your ISP
  • When subscribed Mbps is exactly what is shown, check your internal infrastructure.
  • Check the number of people connected to the wireless device, device might be exceeded the number of users.

Question 9

How can I recover password in Cisco Switch Catalyst 3650, 3850, 9300

Steps:

Press “Mode” button as soon as the SYST light starts flashing green and you get switch into “switch:” mode.

  • switch: flash_init
  • switch: SWITCH_IGNORE_STARTUP_CFG=1
  • switch: boot

From Switch> prompt, enter Enable mode (switch#) and then copy startup-config to running-config..

Note:

Don’t use copy running-config startup-config, you will use all configurations.

  • switch# copy startup-config running-config

Fix issue that you have encountered then save configurations.

Now reboot the switch, get back into switch: mode, and fix the boot variable back to Zero

  • switch: flash_init
  • switch: SWITCH_IGNORE_STARTUP_CFG=0
  • switch: boot

Alternatively to going back into the switch: prompt, some software versions also support the configuration command:

  • (config)#no system ignore startupconfig switch all
  • (config)#end

 

TERNET-Router# write mem

Perform a reload and check the switch

Question 10

How ca I reset Password on my cisco router

Steps:

  • Use the Ctrl + Break function to get the router into Rommon as soon as router is power-cycled.
  • Change the config-register variable to 0x2142 so the router will ignore the startup config in NVRAM, and then reboot the router. As shown below

monitor: command “boot” aborted due to user interrupt

Type as below whatever happens after > and # symbols:

  1. rommon 1 > confreg 0x2142

You must reset or power cycle for new config to take effect

  1. rommon 2 > reset

Router will boot without a configurations.  From the Router> prompt, enter Enable mode, and then copy startup config to running config.

Would you like to enter the initial configuration dialog? [yes/no]: no

Press RETURN to get started!

  1. Router>en
  2. Router#copy startup-config running-config

Destination filename [running-config]?

5413 bytes copied in 5.325 secs (1017 bytes/sec)

————————————————————————————————

Note:

Don’t use

Router# copy running-config startup-config

————————————————————————————————–

  1. Router#

 

Now fix the pasword let you failed to login, save the config and reboot… then get router back into Rommon and set config-register to 0x2102

monitor: command “boot” aborted due to user interrupt

  1. rommon 1 > confreg 0x2102

You must reset or power cycle for new config to take effect

  1. rommon 2 > reset

Router will then reboot and load the saved config, and now you will be able to get into the router at this time, because you will have fixed your password that let you failed login.

Question 11

My Cisco Router stuck on ROMMON mode during boot

Steps:

  1. Use console cable to login the device

Change the configure register value to ignore the startup configuration by issuing the confreg command,

  1. rommon 2> confreg 0x2142

reload the router using reset command

  1. rommon 3> reset

After the router boots up, issue the enable command at the Router> prompt.

  1. Router> enable

It will enter in the privilege mode

  1. Router# prompt

To enter config mode, issue the config terminal command. You should now see a Router(config)# prompt.

  1. Router# configure terminal

To change the configure register to recognize the startup configuration, issue the config-register command, as shown below

  1. Router(config)# config-register 0x2102

Copy start-up config to running-config

Router# copy running-config startup-config

Restart router using reload command

  1. Router# reload

The router will now be ready for uses.

 

 

 

 

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