RE: [Syslog] Discuss - UDP Checksum

[Chris Lonvick <clonvick at cisco.com>]

Hi,

I don't think that addresses the IESG concerns as well as Juergen's 
proposal.

I'd like to wrap this up.  I don't think that there's any disagreement 
that we need something like this.  Would anyone with any other thoughts 
please send them in.  David and I will determine consensus tomorrow.  :-)

Thanks,
Chris

On Tue, 10 Jul 2007, Anton Okmyanskiy (aokmians) wrote:

> I agree with Juergen and Rainer that we could use less specification
> here since it is a different layer.  How about we replace both
> paragraphs with this:
>
> "Syslog senders are RECOMMENDED to use UDP checksums when sending
> messages over IPv4. Proper UDP checksum insertion and verification is
> already required by IPv6 RFC 1883."
>
> Let's be silent on what the receiver has to do since it may not have any
> control.  I think if we put something like "Syslog receivers MAY accept
> syslog message with invalid or zero checksums", it would directly
> contradict IPv6 RFC, which says:
>
> "IPv6 receivers must discard UDP packets containing a zero checksum, and
> should log the error."
>
> Anton.
>
> > -----Original Message-----
> > From: Juergen Schoenwaelder
> > [mailto:j.schoenwaelder at jacobs-university.de]
> > Sent: Thursday, July 05, 2007 4:16 PM
> > To: Chris Lonvick (clonvick)
> > Cc: syslog at ietf.org
> > Subject: Re: [Syslog] Discuss - UDP Checksum
> >
> > On Thu, Jul 05, 2007 at 02:14:06PM -0700, Chris Lonvick wrote:
> >
> > > How about the following:
> > >
> > >    syslog senders MUST NOT disable UDP checksums.  syslog
> > senders SHOULD
> > >    use UDP checksums when sending messages over IPv4.
> > syslog senders MUST
> > >    use UDP checksums when sending messages over IPv6.
> >
> > The last sentence is a bit like requiring that the IPv6
> > implementation your code happens to run on MUST be correct
> > (and I have no clue how to turn this requirement into syslog code).
> >
> > >    syslog receivers should be lenient in what they receive.  IPv4
> > >    receivers SHOULD check the UDP checksums.  They SHOULD accept a
> > >    syslog message with a zero checksum.  They MAY discard messages
> > >    with invalid checksums, or they MAY accept them and
> > attempt to process
> > >    them.  IPv6 receivers MUST check the UDP checksums and
> > MUST discard UDP
> > >    packets containing a zero checksum.
> >
> > I am not sure the MAY discard or MAY accept sentence is needed.
> >
> > My proposal would be:
> >
> >     syslog senders MUST NOT disable UDP checksums.  IPv4 syslog
> >     senders SHOULD use UDP checksums when sending messages. Note that
> >     RFC 2460 [RFC2460] mandates the use of UDP checksums when sending
> >     UDP datagrams over IPv6.
> >
> >     syslog receivers MUST NOT disable UDP checksum checks. IPv4 syslog
> >     receivers SHOULD check UDP checksums and they SHOULD accept a
> >     syslog message with a zero checksum. Note that RFC 2460 [RFC2460]
> >     mandates the use of checksums for UDP over IPv6.
> >
> > By simply refering to the IPv6 requirement for UDP checksums,
> > we avoid making this also a syslog requirement. I think we
> > should not use MUST language for something that can only be
> > implemented correctly below the syslog software layer.
> >
> > [Enough hair splitting for today. ;-]
> >
> > /js
> >
> > --
> > Juergen Schoenwaelder           Jacobs University Bremen gGmbH
> > Phone: +49 421 200 3587         Campus Ring 1, 28759 Bremen, Germany
> > Fax:   +49 421 200 3103         <http://www.jacobs-university.de/>
> >
> > _______________________________________________
> > Syslog mailing list
> > Syslog at lists.ietf.org
> > https://www1.ietf.org/mailman/listinfo/syslog

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