+
+@cindex DNS cache
+@cindex caching of DNS lookups
+@item --dns-cache=off
+Turn off caching of DNS lookups. Normally, Wget remembers the addresses
+it looked up from DNS so it doesn't have to repeatedly contact the DNS
+server for the same (typically small) set of addresses it retrieves
+from. This cache exists in memory only; a new Wget run will contact DNS
+again.
+
+However, in some cases it is not desirable to cache host names, even for
+the duration of a short-running application like Wget. For example,
+some HTTP servers are hosted on machines with dynamically allocated IP
+addresses that change from time to time. Their DNS entries are updated
+along with each change. When Wget's download from such a host gets
+interrupted by IP address change, Wget retries the download, but (due to
+DNS caching) it contacts the old address. With the DNS cache turned
+off, Wget will repeat the DNS lookup for every connect and will thus get
+the correct dynamic address every time---at the cost of additional DNS
+lookups where they're probably not needed.
+
+If you don't understand the above description, you probably won't need
+this option.
+
+@cindex file names, restrict
+@cindex Windows file names
+@item --restrict-file-names=@var{mode}
+Change which characters found in remote URLs may show up in local file
+names generated from those URLs. Characters that are @dfn{restricted}
+by this option are escaped, i.e. replaced with @samp{%HH}, where
+@samp{HH} is the hexadecimal number that corresponds to the restricted
+character.
+
+By default, Wget escapes the characters that are not valid as part of
+file names on your operating system, as well as control characters that
+are typically unprintable. This option is useful for changing these
+defaults, either because you are downloading to a non-native partition,
+or because you want to disable escaping of the control characters.
+
+When mode is set to ``unix'', Wget escapes the character @samp{/} and
+the control characters in the ranges 0--31 and 128--159. This is the
+default on Unix-like OS'es.
+
+When mode is seto to ``windows'', Wget escapes the characters @samp{\},
+@samp{|}, @samp{/}, @samp{:}, @samp{?}, @samp{"}, @samp{*}, @samp{<},
+@samp{>}, and the control characters in the ranges 0--31 and 128--159.
+In addition to this, Wget in Windows mode uses @samp{+} instead of
+@samp{:} to separate host and port in local file names, and uses
+@samp{@@} instead of @samp{?} to separate the query portion of the file
+name from the rest. Therefore, a URL that would be saved as
+@samp{www.xemacs.org:4300/search.pl?input=blah} in Unix mode would be
+saved as @samp{www.xemacs.org+4300/search.pl@@input=blah} in Windows
+mode. This mode is the default on Windows.
+
+If you append @samp{,nocontrol} to the mode, as in
+@samp{unix,nocontrol}, escaping of the control characters is also
+switched off. You can use @samp{--restrict-file-names=nocontrol} to
+turn off escaping of control characters without affecting the choice of
+the OS to use as file name restriction mode.