Chapter1 Cisco SDM Express
Supplementary Help
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Cisco SDM Express
OL-7141-04
The configuration that will be delivered to the router to disable ICMP host
unreachable messages is as follows:
int
<all-interfaces>
no ip unreachables
You can undo this fix using the CiscoSD M Security Audit feature. To learn how,
see the Securi ty Audit online h elp in Cisco SDM. For more information, click
CiscoRouter and Security Device Manager.
Disable IP Mask Reply
Cisco SDM Express disables Internet Message Control Protocol (ICMP) mask
reply messages whenever possible. ICMP supports IP traffic by relaying
information about paths, routes, and network conditions. ICMP mask reply
messages are sent when a network device must know the subnet mask for a
particular subnetwork in the internetwork. ICMP mask reply messages are sent to
the device requesting the information by devices that have the requested
information. These messages can be used by an attacker to gai n network mapping
information.
The configuration that will be delivered to the router to disable ICMP mask reply
messages is as follows:
no ip mask-reply
You can undo this fix using the CiscoSD M Security Audit feature. To learn how,
see the Securi ty Audit online h elp in Cisco SDM. For more information, click
CiscoRouter and Security Device Manager.
Set Minimum Password Length to Less Than 6 Characters
Cisco SDM Express configures your router to require a minimum password
length of 6 characters whenever possible. One method attackers use to crack
passwords is to try all possible combinations of characters until the password is
discovered. Longer passwords have exponentially more possible combinations of
characters, making this method of attack much more difficult.
This configuration change will require every password on the router, including the
user, enable, secret, console, AUX, tty, and vty passwords, to be at least 6
characters in length. This configuration change will be made only if the CiscoIOS
version running on your router supports the minimum password length f eature.