Re: [apps-discuss] Trace headers, was Adoption of draft-kucherawy-received-state?

[SM <[e-mail]>]

Hi John,
At 19:55 14-01-2012, John R. Levine wrote:
>If you believe what the RFCs say, there are many more trace headers 
>than those two.  RFC
>  5322 makes a special case of Resent-foo: fields, but they act an 
> awful lot like trace headers.  RFC 5451 says that 
> Authentication-Results "should be treated as a Trace Field."  RFC 
> 5436 says "The 'Auto-Submitted' header field is considered a 'trace 
> field'". RFC 4408 says that "The Received-SPF header field is a 
> trace field."  RFC 5518 says "VBR-Info is a 'trace header field'". 
> That horse left the barn a long time ago. RFC 5537 also lists a 
> bunch of trace fields for usenet, which isn't mail, but it might be 
> a good idea to reserve them to avoid collisions.

The Auto-Submitted header field is defined in RFC 3834.  It 
references RFC 2822 normatively.  RFC 5451 defines 
Authentications-Results and references RFC 5322 normatively.  RFC 
5518 (VBR-Info) references RFC 5322 normatively.  RFC 4408 references 
RFC 2822 normatively.  RFC 5518 likely used the same path as RFC 
5451.  RFC 3834 does not mention Trace Field but RFC 5436 does.

I would say that some of the header fields were defined as "trace 
fields" to restrict the ordering of existing "trace fields header 
lines".  RFC 5322 contains a requirement not to reorder "trace header 
fields".  Most of the header fields can be traced backed to RFC 5322 
as that document defines a syntax for text messages.  Beliefs in RFCs 
could be traced back to the feature sought.

Regards,
-sm