Chapter 1 Cisco SDM Express
Supplementary Help
Enable TCP Keepalives for Outbound Telnet Sessions
Cisco SDM Express enables TCP keepalive messages for both inbound and outbound Telnet sessions whenever possible. Enabling TCP keepalives causes the router to generate periodic keepalive messages, letting it detect and drop broken Telnet connections.
The configuration that will be delivered to the router to enable TCP keepalives for outbound Telnet sessions is as follows:
service
You can undo this fix using the Cisco SDM Security Audit feature. To learn how, see the Security Audit online help in Cisco SDM. For more information, click Cisco Router and Security Device Manager.
Enable Sequence Numbers and Time Stamps on Debugs
Cisco SDM Express enables sequence numbers and time stamps on all debug and log messages whenever possible. Time stamps on debug and log messages indicate the time and date that the message was generated. Sequence numbers indicate the sequence in which messages that have identical time stamps were generated. Knowing the timing and sequence that messages are generated is an important tool in diagnosing potential attacks.
The configuration that will be delivered to the router to enable time stamps and sequence numbers is as follows:
service timestamps debug datetime localtime
Enable IP CEF
Cisco SDM Express enables Cisco Express Forwarding or Distributed Cisco Express Forwarding whenever possible. Because there is no need to build cache entries when traffic starts arriving at new destinations, Cisco Express Forwarding behaves more predictably than other modes when presented with large volumes of traffic addressed to many destinations. Routes configured for Cisco Express Forwarding perform better under SYN attacks than routers using the traditional cache.
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