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Practical Exercise 3-1 Solution

Use the following steps to configure a modem on the AUX port for EXEC dial-in connectivity:

Step 1. Connect the cable from the router AUX port to the modem.

The AUX port on a Cisco router is either RJ-45 or DB-25. If the AUX port is RJ-45, use a flat-satin rolled RJ-45-RJ-45 cable (part number CAB-500RJ=), which is usually provided with every Cisco router for console connections. You also need an RJ-45-to-DB-25 adapter marked "MODEM" (part number CAB-25AS-MMOD) to connect the rolled cable to the DB-25 port on the modem, as shown in Figure 3-5.

Figure 3-5. Connecting the Rolled Cable to the DB-25 Port on the Modem

If your router has a DB-25 AUX port, use a straight-through DB-25Female-DB25Male RS-232 cable to connect the modem to the router.

Step 2. Use the show line command to determine the AUX port's async interface. Although most routers have the AUX port as line 1, access servers have the AUX port interface after the TTY lines. For example, if your router has 16 async/modem lines, the AUX port is line 17. Configure the AUX port based on the show line outputs. Example 3-10 verifies that the AUX port configuration is on interface line 65.

Example 3-10. show line Command Output

R1#show line
   Tty Typ     Tx/Rx    A Modem  Roty AccO AccI   Uses   Noise  Overruns   Int
*    0 CTY              -    -      -    -    -      0       0     0/0       -
    65 AUX   9600/9600  -    -      -    -    -      0       1     0/0       -
    66 vty              -    -      -    -    -      0       0     0/0       -
    67 vty              -    -      -    -    -      0       0     0/0       -
    68 vty              -    -      -    -    -      0       0     0/0       -
    69 vty              -    -      -    -    -      0       0     0/0       -
    70 vty              -    -      -    -    -      0       0     0/0       -

Step 3. Use the commands shown in Example 3-11 to configure the router AUX line.

Example 3-11. Line Configuration

R1(config)#line 65
R1(config-line)#modem inout
R1(config-line)#speed 115200
R1(config-line)#transport input all
R1(config-line)#flowcontrol hardware
R1(config-line)#login
R1(config-line)#password cisco

Step 4. Reverse-Telnet to the modem and configure the appropriate initialization string, as shown in Example 3-12.

Example 3-12. Modem Configuration via Reverse Telnet

R1#telnet 172.22.53.145 2065
Trying 172.22.53.145, 2065 ... Open
at
OK
at&f1s0=1
OK
at&w
OK
R1#disconnect 1
Closing connection to 172.22.53.145 [confirm]
R1#

Step 5. Use an analog phone to verify that the phone line is active and functioning. Then connect the analog phone line to the modem.

Step 6. Test the modem connection by initiating an EXEC modem call to the router from another device (for example, a PC). Use a terminal emulation program on the PC, such as Hyperterminal, and access the PC's modem through one of the COM ports. Once you have connected to the PC's modem through the COM port, initiate the dial to the router.

Step 7. As soon as the connection is established, the dial-in client is prompted for a password. Enter the correct password. This password must match the one configured on the AUX port line.

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