Messages in this thread | | | Date | Sun, 22 Jun 2008 11:19:40 +0300 | From | "Christian P. Schmidt" <> | Subject | Sending UDP packets to port 0 |
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Hi all,
I know that the kernel forbids sending UDP packets to port 0. Is there a specific reason for this?
I'm asking because I regularly need to access a device that asks for tftp files using port 0 as source. To use these devices I'm using a kernel with removed port 0 checks.
I read RFC 768, and it does not explicitly forbid the use of port 0 as far as I can see. It only says that if unused, 0 is to be inserted.
RFC 1350 (TFTP) even states explicitly: The transfer identifiers (TID's) used by TFTP are passed to the Datagram layer to be used as ports; therefore they must be between 0 and 65,535.
In my understanding, and apparently that of the authors of the appliance's tftp client implementation, this marks port 0 as valid.
Please CC: me on any replies as I am not subscribed to the list.
Regards, Chris
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