Cisco Cisco ASA for Nexus 1000V Series Switch Guia De Resolução De Problemas
Microsoft Windows Dialup Networking (DUN) for this connection.
Once the connection is established, press <Return> in order to obtain the prompt on the ASA.
Once the connection is established, press <Return> in order to obtain the prompt on the ASA.
12.
Console Port Issues
There are several advantages to connecting a modem to the console port of an ASA. However, the
disadvantages are significant.
disadvantages are significant.
Advantages When You Connect a Modem on the Console Port
You can recover passwords remotely. You might still need someone on−site with the ASA to toggle
the power. Aside from that, it is identical to being there with the ASA.
the power. Aside from that, it is identical to being there with the ASA.
•
It is a convenient way to attach a modem to an ASA without async ports. This is beneficial if you
need to access the ASA for configuration or management.
need to access the ASA for configuration or management.
•
Disadvantages When You Connect a Modem on the Console Port
The console port does not support RS232 modem control (Data Set Ready/Data Carrier Detect
(DSR/DCD), Data Terminal Ready (DTR)). Therefore, when the EXEC session terminates (logout),
the modem connection does not drop automatically. The user needs to manually disconnect the
session.
(DSR/DCD), Data Terminal Ready (DTR)). Therefore, when the EXEC session terminates (logout),
the modem connection does not drop automatically. The user needs to manually disconnect the
session.
•
More seriously, if the modem connection does drop, the EXEC session does not automatically reset.
This can present a security hole, in that a subsequent call into that modem is able to access the console
without entering a password. You can make the hole smaller when you set a tight exec−timeout on the
ASA. However, if security is important, use a modem that can provide a password prompt.
This can present a security hole, in that a subsequent call into that modem is able to access the console
without entering a password. You can make the hole smaller when you set a tight exec−timeout on the
ASA. However, if security is important, use a modem that can provide a password prompt.
•
Unlike other async lines, the console port does not support hardware (Clear to Send/Ready to Send
(CTS/RTS) flow control. Cisco recommends that you use no flow control. If data overruns are
encountered, however, you can enable software (XON/XOFF) flow control.
(CTS/RTS) flow control. Cisco recommends that you use no flow control. If data overruns are
encountered, however, you can enable software (XON/XOFF) flow control.
•
The console port lacks reverse Telnet capability. If the modem loses its stored initialization string, the
only remedy is to physically disconnect the modem from the ASA and attach it to another device
(such as a PC) to reinitialize.
only remedy is to physically disconnect the modem from the ASA and attach it to another device
(such as a PC) to reinitialize.
•
You cannot use a console port for dial−on−demand routing because it has no corresponding async
interface.
interface.
•
Miscellaneous
Dip Switches
This table contains a list of the functions of the DIP switches on a US Robotics modem:
ON = Down, OFF = Up
Dip Switch
Description
1
DTR Override
2
Verbal/Numeric Result Codes
3
Result Code Display
4
Command Mode Local Echo Suppression
5
Auto Answer Suppression
6
CD Override