Path: utzoo!attcan!uunet!hsi!stevens
From: stevens@hsi.UUCP (Richard Stevens)
Newsgroups: comp.protocols.tcp-ip
Subject: Re: UDP checksums
Keywords: UDP checksum sun
Message-ID: <1812@hsi86.hsi.UUCP>
Date: 17 Jul 90 10:21:55 GMT
References: <5@wotk.UUCP> <1990Jul17.003242.1556@ultra.com>
Reply-To: stevens@hsi.com (Richard Stevens)
Organization: 3M Health Information Systems, Wallingford, CT.
Lines: 23

In article <1990Jul17.003242.1556@ultra.com> beau@ultra.com (Beau James writes:
>
>UDP checksums must be enabled on both sending and receiving
>machines before the software will compute and verify the
>checksum.

Newer systems should start conforming to the Host Requirements RFC (1122),
meaning the receiver has to honor a checksum that was set by the sender:

         4.1.3.4  UDP Checksums

            A host MUST implement the facility to generate and validate
            UDP checksums.  An application MAY optionally be able to
            control whether a UDP checksum will be generated, but it
            MUST default to checksumming on.

            If a UDP datagram is received with a checksum that is non-
            zero and invalid, UDP MUST silently discard the datagram.
            An application MAY optionally be able to control whether UDP
            datagrams without checksums should be discarded or passed to
            the application.

/Richard Stevens