TCP Keepalive


A well-known science laboratory specialized in researching “portal” technology has a small network running OSPF. One of their terminals is used by a scientist to reach a central server. However every time router Alive crashes it’s impossible to re-connect to the central server. Besides a scientist you are also a network engineer, let’s see if you can portal yourself out of this one…


  • All IP addresses have been preconfigured for you.
  • OSPF has been configured for connectivity.
  • Configuge router Terminal so it detects dead TCP connections and closes them.
  • You can test this by using telnet on router Server to router Terminal and shutting the F1/0 interface on router Alive afterwards to simulate a dead connection.




TCP Keepalive

Video Solution:

Configuration Files

You need to register to download the GNS3 topology file. (Registration is free!)

Once you are logged in you will find the configuration files right here.

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Written by René Molenaar - CCIE #41726

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About the Author: Rene Molenaar

René - CCIE #41726 is the creator of where he shares CCNA, CCNP and CCIE R&S labs. He also blogs about networking on

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