All of lore.kernel.org
 help / color / mirror / Atom feed
From: "Christian P. Schmidt" <schmidt@digadd.de>
To: linux-kernel@vger.kernel.org
Subject: Sending UDP packets to port 0
Date: Sun, 22 Jun 2008 11:19:40 +0300	[thread overview]
Message-ID: <485E0B1C.7030105@digadd.de> (raw)

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

             reply	other threads:[~2008-06-22  8:55 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-06-22  8:19 Christian P. Schmidt [this message]
2008-06-22  9:11 ` Sending UDP packets to port 0 Jan Engelhardt
     [not found] <aHtAJ-8bW-11@gated-at.bofh.it>
2008-06-22 10:02 ` Alan Jenkins

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=485E0B1C.7030105@digadd.de \
    --to=schmidt@digadd.de \
    --cc=linux-kernel@vger.kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.