If you are using putty with serial port. To access rommon mode press
Ctrl + Shift + Break or Pause.
And if you are using Terra Term with serial port press
Alt + B
Configure aux 0 for reverse telnet.
conf term
line aux 0
modem InOut
transport input all
exit
!
How to find line number for aux 0
R01#show line
Tty Line Typ Tx/Rx A Modem Roty AccO AccI Uses Noise Overruns Int
0 0 CTY - - - - - 0 0 0/0 -
* 1 1 AUX 9600/9600 - inout - - - 0 0 0/0 -
* 514 514 VTY - - - - 50 1 0 0/0 -
515 515 VTY - - - - 50 0 0 0/0 -
!
Now that found line number for aux 0 is line number 1.
IP address of the router 2000 + line number 1
Is telnet 10.1.1.1 2001
R01#telnet 10.1.1.1 2001
Trying 10.1.1.1, 2001 ...
% Connection refused by remote host
R01#clear line 1
[confirm]
[OK]
R01#telnet 10.1.1.1 2001
Trying 10.1.1.1, 2001 ... Open
User Access Verification
Username: admin
Password:
PPPOE#
PPPOE#
PPPOE#
Then what to do with reverse telnet how to access rommon mode ?
( Ctrl + Shift + 6 ) release and then press B
System Bootstrap, Version 12.4(13r)T11, RELEASE SOFTWARE (fc1)
Technical Support: http://www.cisco.com/techsupport
Copyright (c) 2009 by cisco Systems, Inc.
Initializing memory for ECC
.
c2811 platform with 262144 Kbytes of main memory
Main memory is configured to 64 bit mode with ECC enabled
Upgrade ROMMON initialized
PC = 0xbfcd0d54, Cause = 0x2000, Status Reg = 0x3040a803
monitor: command "boot" aborted due to user interrupt
rommon 1 >
rommon 1 >
rommon 1 >
rommon 1 > confreg 0x2142
You must reset or power cycle for new config to take effect
rommon 2 > reset
After reset.
Router>en
Router#copy start running-config
Destination filename [running-config]?
2991 bytes copied in 12.400 secs (241 bytes/sec)
PPPOE#
PPPOE#conf term
Enter configuration commands, one per line. End with CNTL/Z.
PPPOE(config)#config 0x2102
PPPOE(config)#end
PPPOE#
*Apr 30 04:55:47.419: %SYS-5-CONFIG_I: Configured from console by console
PPPOE#show version
Configuration register is 0x2142 (will be 0x2102 at next reload)
PPPOE#
Then to exit reverse telnet.
( Ctrl + Shift + 6) release and then press X
https://supportforums.cisco.com/discussion/11390416/how-do-you-send-break-putty-cisco-2600-terminal-server
http://www.cisco.com/c/en/us/td/docs/ios/termserv/configuration/guide/15-mt/tsv-15-MT-book/tsv_dialin_term_svcs.html
https://networklessons.com/network-services/cisco-terminal-server-configuration-example/
http://ciscofaq.blogspot.com/2005/05/how-to-i-reverse-telnet-out-my-aux.html
https://supportforums.cisco.com/discussion/10680346/me-3400-password-recovery