Linux Server Hacks
by Rob Flickenger

This errata page lists errors outstanding in the most recent printing.

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 February 02, 2006.

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


Confirmed errors:


[27, 28]  List: Makefile.mail, Makefile.push;
All lines in these Makefiles are shifted to the left margin, which won't work for
Makefiles--they need tab indents following a target.

E.g., not:
aliases.db: aliases
newaliases

SHOULD BE:
aliases.db: aliases
<TAB>newaliases


[139-140] In the printing that has [3/03*] on the copyright page,
the chapter start of Chapter 6 is missing (which includes the
beginning of Hack #66).

Here is a PDF of the missing page: 
http://examples.oreilly.com/linuxsvrhack/ch06_chap_start.pdf


(161)  Top paragraph;
"Only quarriers whose IP addresses match ..."
change "quarriers" to "queriers"


[210]  Center of page (VirtualHost configuration snippet);
The ProxyPassReverse directive doesn't (yet) support environment variables.
AUTHOR: This is correct.  Setting an environment variable within a
ProxyPassReverse directive doesn't have the intended effect.  It
doesn't interpolate the variable, completely breaking the reverse
proxy.  Restarting Apache with this directive in place doesn't even
throw any warnings.  Evidently, environment variables are only used
with the following directives:

BrowserMatch
BrowserMatchNoCase
PassEnv
RewriteRule
SetEnv
SetEnvIf
SetEnvIfNoCase
UnsetEnv

This means that any redirects handed out by the back-end servers in the
example don't get rewritten properly.  Comment out the ProxyPassReverse
line, and tell the fine folks at Apache just how useful environment
variables would be in ProxyPassReverse!

As a (horrible) workaround, you can list multiple ProxyPassReverse
lines in a single VirtualHost entry, but this defeats the whole purpose
of an automated proxy.  The rest of the Hack still works unless
back-end servers hand back redirects to themselves.  They should use
external, fully qualified redirects to avoid this problem.