I was asked to troubleshoot a problem in IMSciences network, actually they were unable to connect to Islamabad HEC office (Vedio Confencing) and they also need to send the vedio trafic and voice traffic using one interface on router (3800-series) so after some research i have done with the problem and sloved for it. Actually i done with some VLAN configuration, Define some static Routes, enable routing, use sub interfaces and i was successfull to ping the destination.
Then the person who called me for the problem solution told me about the mistake of MS student who is working there as a internee while recovering password. IMSciences lost their startup configurations and face trouble both by the institute and the student as they get disconnected from the network, now they were unable to do the configuration, any how they ship the router back to PTCL for configurations.
So here i am going to tell you about the step that you must take care of while recovering your router password.
1: Boot your router and interrupt the boot sequence by performing a break sequence using Ctrl+Break key combination.
2: Change the configuration register to turn on bit 6 (0x2142)
rommon> confreg 0x2142
You must reset or power cycle for new config to take effect
3: Reload the router, type reset
The router will reload and ask if you want to enter setup mode, so your answer will be NO
4: Enter Privileged mode
Router > enable
NOTE: Now this is the step where you to take care many people just change the password and copy the configuration to startup configuration and here they make a mistake as you over-write the whole (original) configurations. so the correct sequence is:
5: Copy the startup-configuration to running-configuration
Router # copy startup-config running-config
6: change the password
Router # config terminal
Router (config) # enable secret cisco
7: Reset the configuration register to the default value
Router (config) # config-register 0x2102
8: save your configurations
Router # copy running-config startup-config
9: Relaod your router