Cooling system—Consists of four fans in the Cisco 4000 Series Integrated Services Routers system board. Each PSU has its own fans. Normal Router Startup Sequence. You can generally determine when and where the power supply failed during the startup sequence by checking the status LEDs on the power supply modules.
![]() ContentsIntroduction
This document describes how to recover the enable password and the enable secret passwords. These passwords protect access to privileged EXEC and configuration modes. The enable password password can be recovered, but the enable secret password is encrypted and must be replaced with a new password. Use the procedure described in this document in order to replace the enable secret password.
Note: Refer to Password Recovery Procedure for the Cisco 801, 802, 803, 804, 805, 811, and 813 Series Routers in order to recover a password on the Cisco 801, 802, 803, 804, 805, 811, and 813 Series Routers.
![]() PrerequisitesRequirements
There are no specific requirements for this document.
Components Used
The information in this document is based on these hardware versions:
The information in this document was created from the devices in a specific lab environment. All of the devices used in this document started with a cleared (default) configuration. If your network is live, make sure that you understand the potential impact of any command.
Related Products
Refer to Password Recovery Procedures for information on how to recover passwords for related products.
Conventions
Refer to Cisco Technical Tips Conventions for information on document conventions.
Step-by-Step Procedure
Follow these steps in order to recover your password:
Example of Password Recovery Procedure
This section provides an example of the password recovery procedure. This example was created with a Cisco 2600 Series Router. Even if you do not use a Cisco 2600 Series Router, this output provides an example of what you should experience on your product.
Related InformationContentsIntroduction
A terminal or comm server commonly provides out-of-band access for multiple devices. A terminal server is a router with multiple, low speed, asynchronous ports that are connected to other serial devices, for example, modems or console ports on routers or switches.
The terminal server allows you to use a single point to access the console ports of many devices. A terminal server eliminates the need to configure backup scenarios like modems on auxiliary ports for every device. You can also configure a single modem on the auxiliary port of the terminal server, to provide dial-up service to the other devices when network connectivity fails.
This document shows how to configure a terminal server to access only the console ports on other routers through Reverse Telnet. Reverse Telnet allows you to establish a Telnet connection out on the same device you telnet from, but on a different interface. For more information on Reverse Telnet refer to Establishing a Reverse Telnet Session to a Modem.
PrerequisitesRequirements
There are no specific requirements for this document.
Components Used
This document is not restricted to specific software and hardware versions.
Conventions
For more information on document conventions, refer to the Cisco Technical Tips Conventions.
The information in this document was created from the devices in a specific lab environment. All of the devices used in this document started with a cleared (default) configuration. If your network is live, make sure that you understand the potential impact of any command.
Cabling
The Cisco 2509 - 2512 series routers use a 68-pin connector and breakout cable. This cable (CAB-OCTAL-ASYNC) provides eight RJ-45 rolled cable async ports on each 68-pin connector. You can connect each RJ-45 rolled cable async port to the console port of a device. The 2511 router allows for a maximum of 16 devices to be remotely accessible. In addition, the NM-16A or NM-32A high density async network modules are available for the Cisco 2600 and 3600 series routers to provide the same function. For more information on cabling refer to the Let's Connect:Your Serial Cable Guide and the Cabling Guide for Console and AUX Ports.
Note: The async ports from the 68-pin connector are data terminal equipment (DTE) devices. DTE to DTE devices require a rolled (null modem) cable and DTE to data circuit-terminating equipment (DCE) devices require a straight-through cable. The CAB-OCTAL-ASYNC cable is rolled. Therefore, you can connect each cable directly to the console ports of devices with RJ-45 interfaces. However, if the console port of the device to which you connect is a 25-pin interface (DCE), you must use the RJ-45 to 25-pin adapter marked 'Modem' (to reverse the 'roll') in order to complete the connection.
This table shows the port types for console and auxiliary ports on Cisco routers and switches:
Design Strategy
Configure the terminal server so that you can access the terminal server from anywhere. In order to make the terminal server accessible, assign a registered public Internet address, and locate the server outside the firewall. When you do so, firewall issues do not interrupt your connection. You can always maintain connectivity to the terminal server and access the connected devices. If you are concerned about security, configure access lists to allow access only to the terminal server from certain addresses. For a more robust security solution, you can also configure server-based authentication, authorization, and accounting (AAA) for example, RADIUS or TACACS+. For more information on AAA, refer to Authentication, Authorization, and Accounting (AAA).
You can configure a modem on the auxiliary port of the terminal server for dial backup in the event your primary connection (through the Internet) goes down. Such a modem eliminates the need to configure a dial backup for each device. The terminal server is connected through its async ports to the console ports of the other devices. For more information on how to connect a modem to the AUX port, refer to Modem-Router Connection Guide.
Use the ip default gateway statement, and point to the the next hop router on the Internet. This command enables you to have connectivity to the terminal server through the Internet even if routing is not enabled. For example, the terminal server is in ROM monitor (ROMMON) mode as a result of a bad reboot after a power outage.
Configure
In this section, you are presented with the information to configure the features described in this document.
Note: To find additional information on the commands used in this document, use the Command Lookup Tool (registered customers only) .
Network Diagram
This document uses this network setup:
Configurations
This document uses this configuration:
Note: If you use the 3600 as the access-server, refer to How Async Lines are Numbered in Cisco 3600 Series Routers for line number details.
![]() Command Summary
ip host âUse this command to define the name-to-address mapping of the static host in the host cache. in order to remove the name-to-address mapping, use the no form of this command.
transport inputâUse this command to define the protocols to use when you connect to a specific line of the router.
telnetâUse this EXEC command to log into a host that supports Telnet.
Switch Between Active Sessions
Complete these steps in order to switch between active sessions:
Terminate Active Sessions
Complete these steps to terminate a particular Telnet session:
Verify
This section provides information you can use to confirm your configuration is working properly.
Certain show commands are supported by the Output Interpreter Tool (registered customers only) , which allows you to view an analysis of show command output.
Troubleshoot
This section provides information you can use to troubleshoot your configuration.
Troubleshooting Procedure
Follow these instructions to troubleshoot your configuration.
If you cannot connect to the router of your choice with a name configured in the ip host command check:
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