Command Authorization; Protection From Tcp Tiny And Overlapping Fragment Attacks - Dell Force10 C150 Configuration Manual

To delete a TACACS+ server host, use the
freebsd2# telnet 2200:2200:2200:2200:2200::2202
Trying 2200:2200:2200:2200:2200::2202...
Connected to 2200:2200:2200:2200:2200::2202.
Escape character is '^]'.
Login: admin
Password:
FTOS#
FTOS#

Command Authorization

The AAA command authorization feature configures FTOS to send each configuration command to a
TACACS server for authorization before it is added to the running configuration.
By default, the AAA authorization commands configure the system to check both EXEC mode and
CONFIGURATION mode commands. Use the command
only EXEC mode command checking.
If rejected by the AAA server, the command is not added to the running config, and messages similar to
Message 1 are displayed.
Message 1 Configuration Command Rejection
04:07:48: %RPM0-P:CP %SEC-3-SEC_AUTHORIZATION_FAIL: Authorization failure
authorization failed for user (denyall) on vty0 ( 10.11.9.209 )
Protection from TCP Tiny and Overlapping Fragment
Attacks
Tiny and overlapping fragment attack is a class of attack where configured ACL entries—denying TCP
port-specific traffic—can be bypassed, and traffic can be sent to its destination although denied by the
ACL. RFC 1858 and 3128 proposes a countermeasure to the problem. This countermeasure is configured
into the line cards and enabled by default.
SCP and SSH
Secure Shell (SSH) is a protocol for secure remote login and other secure network services over an
insecure network. FTOS is compatible with SSH versions 1.5 and 2, both the client and server modes. SSH
sessions are encrypted and use authentication.
no tacacs-server host
{
hostname
no aaa authorization config-commands
| } command.
ip-address
to enable
Command
Security | 935