There are a lot of Cisco router
errors out there. Way too many, right?

Quick fix

The service configuration error „%Error opening tftp” occurs during initial hardware bootup through Cisco IOS software.

To solve the problem, issue the no service config global command:

Router#config terminal

Enter configuration commands, one per line. 

Router(config)#no service config

Router(config)#exit

Router#copy running-config startup-config

The error message will not come up again at the next bootup of the Cisco router.

Best solution:

https://www.cisco.com/c/en/us/support/docs/routers/10000-series-routers/49683-serviceconfig-error-msgs.html

Quick fix

ASA interface overrun errors occur when a packet is received on the network interface, but cannot be stored due to a lack of capacity. The error can be caused both on a software and on a hardware level.

1. Check if the Adaptive Security Appliance (ASA) experiences CPU hogs that cause the problem. Try to reduce CPU hogs.
2. Determine if the ASA is oversubscribed due to the traffic profile of the interface traffic rates.
3. Check if the problem is caused by intermittent traffic bursts. If this is the case, implement flow control to the ASA interface.

Best solution:

Click here.

Quick fix

There are several problems that can cause the Cisco router to get stuck in ROMmon mode. Most commonly, the error is caused during the boot process.

1. If your router gets stuck in ROMmon mode during the boot process, examine the value of the configuration register by entering the confreg command.
2. Change the value of the configuration register as shown below to stop the router to go into the ROMmon mode after reloading.
   
   
   

   rommon 2 > confreg
       Configuration Summary
   enabled are: 
   load rom after netboot fails
   console baud: 9600
   boot: the ROM Monitor
   do you wish to change the configuration? y/n [n]: y
   enable "diagnostic mode"? y/n [n]: 
   enable "use net in IP bcast address"? y/n [n]: 
   disable "load rom after netboot fails"? y/n [n]: 
   enable "use all zero broadcast"? y/n [n]: 
   enable "break/abort has effect"? y/n [n]: 
   enable "ignore system config info"? y/n [n]: 
   change console baud rate? y/n [n]: 
   change the boot characteristics? y/n [n]: y
   enter to boot:
    0 = ROM Monitor
    1 = the boot helper image
    2-15 = boot system
       [0]: 2
       Configuration Summary
   enabled are:
   load rom after netboot fails
   console baud: 9600
   boot: image specified by the boot system commands
       or default to: cisco2-C2600
   do you wish to change the configuration? y/n [n]: n
   You must reset or power cycle for new config to take effect.
   rommon 3> reset

Best solution:

https://www.routerfreak.com/router-stuck-rommon-mode/

Quick fix

If you encounter Cisco router error code 448, you receive the message “Dialog (%1) aborted and was deleted”. Error 448 is not a routing error, but occurs when the customer leg disconnected for the call at the routing client.

1. Go to the program menu and select ICM Admin Workstation > Schema Help > Contents > ICM Master Help Option > Help Option.
2. Select your router’s name and click on ICM error. Wait for the error popup window to appear. Scroll through the error message.
3. Apply patches through SR2 or hotfix 162 for ICM 4.6.2 to adjust the way error code 448 is used for abandoning calls. Check your router to make sure that the problem is solved.

Best solution:

https://www.myblog2u.com/resolve-cisco-error-code-448/