Nov
28
2008
0

traceroute Fails with -F (do not fragment bit) Argument

With traceroute-1.4a12-XX  the -F argument is used to avoid intra-switch fragmentation. From traceroute(8) manpage:

       ...
       -F     Set the "don’t fragment" bit.
       ...

When ‘-F’  is specified the traceroute fails to get connected. Even with localhost: (more…)

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Nov
28
2008
0

Extra Data Received on Transport in Urgent Mode (MSG_OOB)

While transmitting data in Urgent Mode  at the socket layer:

  • Urgent mode is initiated using send(…, MSG_OOB),
  • Current outgoing queue is longer than MTU
  • Several packets are sent out with the URG flag set.

The Urgent Pointer field in the TCP header is not updated correctly. Instead, it stays the same. (more…)

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Written by in: kernel,linux,network | Tweet This

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