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A traceroute implementation using TCP packets PR: 36177 Submitted by: Jeff Wheat <jeff@cetlink.net>
17 lines
967 B
Text
17 lines
967 B
Text
tcptraceroute is a traceroute implementation using TCP packets.
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The more traditional traceroute(8) sends out either UDP or ICMP ECHO packets
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with a TTL of one, and increments the TTL until the destination has been
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reached. By printing the gateways that generate ICMP time exceeded messages
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along the way, it is able to determine the path packets are taking to reach
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the destination.
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The problem is that with the widespread use of firewalls on the modern
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Internet, many of the packets that traceroute(8) sends out end up being
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filtered, making it impossible to completely trace the path to the destination.
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However, in many cases, these firewalls will permit inbound TCP packets to
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specific ports that hosts sitting behind the firewall are listening for
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connections on. By sending out TCP SYN packets instead of UDP or ICMP ECHO
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packets, tcptraceroute is able to bypass the most common firewall filters.
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WWW: http://michael.toren.net/code/tcptraceroute/
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