Stopping Spam
by Alan Schwartz and Simson Garfinkel 


Most of the unconfirmed errors have been suggested by readers.  They have 
not yet been approved or disproved by the author or editor and represent 
solely the opinion of the reader.

If you have technical questions or error reports, you can send them to
booktech@oreilly.com.  Please specify the printing date of your copy.


This page was updated April 9, 2001.


Here's a key to the markup:

        [page-number]: serious technical mistake
        {page-number}: minor technical mistake
        <page-number>: important language/formatting problem
        (page-number): language change or minor formatting problem
        ?page-number?: reader question or request for clarification


UNCONFIRMED errors and comments from readers:


{20}  Section about Christmas "virus";
The technical definition of a "computer virus" includes the condition that a 
virus should be able to replicate itself. The Christmas worm did not self-
replicate, and is thus technically a "worm," not a "virus."


{43}  In the third line from the bottom, the term "dotted octet" is incorrect. 
The term probably intended here is "dotted quad." An IP address contains four 
octets (sic) but they are not, by themselves, "dotted" (and in any case, 
calling an IP address "an ... octet" is definitely incorrect).


[81]  The Procmail example should use locking; i.e., you should change the :0 
on the first recipe to :0:.

You should use locking always when saving to a file.

For a bit of a treatment of this topic, please refer to the Procmail FAQ at
http://www.iki.fi/era/procmail/mini-faq.html.


[83]  Counting from the top of the page, including empty lines, the Procmail 
example contains the following errors:

line 3: Missing dollar sign prevents $MYNAME from being expanded. Change to:

	* $ ! ^From +$MYNAME

line 5: (Should perhaps also specify -z.)

line 7: Should always use locking when writing to a file; additionally, should 
probably wait for exit status, and ignore any write errors. Thus, change line 
to:

	:0wi:

line 12: (Perhaps you should use $\FILTER_PASSWD instead, in case the password 
would happen to contain regular expression special characters.)

line 14: Should always use locking when writing to a file; add a second colon 
after the c.

line 16: (Should perhaps ignore errors when writing. Add i flag and maybe w 
flag; i.e., change :0 to :0wi).

line 21: (Multiple echos could be substituted with a multiline string instead,
although getting newlines into that is tricky.)


{157}  The hiss.han.de mailing list has not been operational for a long time. 
Some other sites accept spam samples, but do not share their corpus of spam 
with others. I am unaware of any serious heir to the han.de list.


{181}  September 19 item;
The text implies that the ping command is explained in Chapter 7, but I could 
find no such explanation in that chapter.

For what it's worth, the Index has no mention of ping at all.