[CentOS] Apparent bug in logwatch's reporting of number of email by sendmail

[ken]

On 03/16/2015 11:25 AM, Blake Hudson wrote:
>
>>>>
>>>> --------------------- sendmail Begin ------------------------
>>>>
>>>>  STATISTICS
>>>>  ----------
>>>>
>>>>  Bytes Transferred:      5241
>>>>  Messages Processed:     2
>>>>  Addressed Recipients:   2
>>>>
>>>>  ---------------------- sendmail End -------------------------
>>>>
>>>> I'd also like to know where/how logwatch is getting the number for
>>>> "Bytes Transferred"; it doesn't seem to correspond to anything.
>>>>
>>>> So, unless I'm missing something, that's two problems.  Does anyone
>>>> see any others...?  or have a plausible explanation for these
>>>> inconsistencies?
>>>>
>>>> tia.
>>>
>>> Ken, the bytes transferred looks to be the size of the first two log
>>> entries (2485 + 2756 = 5241). I'm not sure what logwatch considers
>>> individual messages in its sendmail stats, but a unique message ID does
>>> indicate a unique message. I also want to point out that if your
>>> logwatch is generating an email, this may be counted in the stats also
>>> (how, I'm not sure). If logwatch is running at 4AM, when these emails
>>> are being sent, I could also anticipate some problems, depending on the
>>> timing involved and when log entries are committed to the log. Overall,
>>> I wouldn't be concerned.
>>>
>>> --Blake
>>
>> My major concern is accuracy.  I mean, there's not much sense in using
>> logwatch if what it's telling me is wrong.
>>
>> The fact that logwatch runs at 4am shouldn't be the problem here, as
>> logwatch is culling data from the previous day.  So no conflict there
>> (if that's what you were implying).
>>
>> You're right about the Bytes Transferred number.  "size" is mentioned
>> *three* times in maillog.  It's just another curiosity how logwatch
>> picked the two numbers that it did.  However it did it, obviously it's
>> double-counting, so logwatch is getting that number wrong as well.
>>
> Based on the day of 'Mar 12', I agree with the bytes transferred.
> Logwatch's sendmail component appears to be using the sendmail queue ID
> (vs the message ID) as an identifier for a unique message. Using this
> identifier, I too count 2 messages (t2C82IiB027383 and t2C82Bjr027151).
> Looking at recipients, I also count two: recip at dest and <recip at dest.com>.

If someone knew absolutely nothing about email, then yes, recip at dest and 
<recip at dest.com> might be seen as two recipients.  But sendmail, an 
inert body of code, knows that those are two ways of addressing one and 
the same recipient and indeed sends me just one email, not one to 
recip at dest and another to recip at dest.com.  Logwatch, however, lacks the 
sophistication to understand that these are simply two ways of 
*addressing*, or *referring* to, one and the same recipient.

Similarly, simply because there are two different numerical identifiers, 
both *referring* to one and the same email doesn't mean there are two 
emails.  If there were a third number referring to that one email would 
we then magically have three emails?  I'm wondering, then, what would 
happen in logwatch if an administrator changed sendmail's loglevel to 
something other than the default...?


>
> What criteria to use as a means of identifying a unique message is
> certainly a choice. I can see how some would choose the MUA's message ID
> instead. However, that may be more error prone given that this is not
> guaranteed to be a unique value within a data set. Sendmail's queue ID
> should be unique in a day's data on a single server.
>
> --Blake

I'll leave the criteria selection as well as the logic to interpret that 
up to the logwatch developer(s).  Perhaps sendmail's logging would need 
to be made less ambiguous for logwatch (and other possible diagnostic 
programs).  Whatever fixes the problem is fine with me.

Blake, thanks for playing devil's advocate and pointing out the probable 
sources of unwarranted conflation.  At first I was a bit unsure, but 
after this conversation we can with certainty conclude that, yes, this 
is a bug.