john heasley wrote:

>A value of zero is a clear
>indication not to check it for UDP.  It seems like little pain to be
>"correct".
>
>I do not know what could be done for IP or TCP checksums.  But, if I'm not
>mistaken, zero is not a valid value for either and might be a good indicator
>that no checksumming was performed.
>  
>
Both IP and TCP checksums MUST be performed.

Zero is not a valid value for UDP, and indicates no checksum.  The field
still must be set to something.  Don't leave uninitialized fields.

-- 
William Allen Simpson
    Key fingerprint =  17 40 5E 67 15 6F 31 26  DD 0D B9 9B 6A 15 2C 32