Task 7 Testing Asynchronous Shell Connections

This task verifies that the following components are working:

• The physical asynchronous data path

• Basic modem links

• Basic IP functionality to support shell sessions

The Cisco IOS provides a command-line interface (CLI) called the EXEC. The EXEC:

• Can be accessed by dialing in with a modem

• Provides access to terminal-shell services (no PPP) to do the following:

- Modify configuration files

- Change passwords

- Troubleshoot possible problems including modem connections

- Access other network resources by using telnet

During this task, some administrators try to make complex services function such as PPP-based Web browsing. Do not jump ahead. Many other elements still need to be configured (for example, PPP and IPCP). The asynchronous-shell test ensures that the EXEC's login prompt can be accessed by a client modem. Taking a layered approach to building a network isolates problems and saves you time.

Step 1 Locate a client PC, client modem, and analog line. From the client PC, open a terminal emulation program (such as Hyper Terminal, not Dial-Up Networking) and connect to the client modem. Figure 2-6 shows the network environment for this test.

Figure 2-6 Test Environment

Figure 2-6 Test Environment

Client PC

Client modem

Client PC

Client modem

Default gateway

Default gateway

Cisco AS5300 with integrated modems

Step 2 From a terminal-emulation program, test your RS-232 connection to the client modem. Enter the at command. The modem returns the prompt "OK."

Step 3 Dial the PRI telephone number assigned to the NAS (in this example the number is 5551234). After the modem successfully connects, a connect message appears.


CONNECT 28800 V42bis

Tech Tip Many modems support the a/ command, which recalls the last AT command. The ath command hangs up a modem call. The atdl command dials the last telephone number.

I Testing Asynchronous-Shell Connections

Step 4 Log into the EXEC session:

This is a secured device. Unauthorized use is prohibited by law.

User Access Verification

Username: dude Password:

Step 5 Identify the line where the call landed. The following example shows that line TTY 1 accepted the call. The call has been up and active for 48 seconds.

5300-NAS>show caller

Line con 0 tty 1

User admin dude


Active Time

00:05:33 00:00:48

Idle Time

00:00:00 00:00:22

53 0 0-NAS>show caller user dude

User: dude, line tty 1, service TTY

Active time 00:01:12, Idle time 00:00:46 Timeouts: Absolute Idle Idle

TTY: Line 1

DS0: (slot/unit/channel)=0/0/0

Line: Baud rate (TX/RX) is 115200/115200, no parity, 1 stopbits, 8 databits Status: Ready, Active, No Exit Banner

Capabilities: Hardware Flowcontrol In, Hardware Flowcontrol Out

Modem Callout, Modem RI is CD, Integrated Modem Modem State: Ready

Note The show caller command is added to the Cisco IOS software in Release 11.3 AA and 12.0 T. If your software release does not support this command, use the show user command.

Step 6 Test the IP functionality to support shell sessions. From the NAS, telnet to another device in your network.

53 0 0-NAS>telnet

User Access Verification

Username: admin Password:

58 0 0-NAS>telnet people

Translating "people"...domain server ( [OK] Trying people.cisco.com ( Open

SunOS 5.6

Confirming the Final Running-Config I

login: dude Password:

Last login: Wed Oct 6 08:57:46 from dhcp-aus-163-236

Sun Microsystems Inc. SunOS 5.6 Generic August 1997

/cms/resource/.cmsrc: No such file or directory people%

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