It's important to understand how the allow/deny directives are parsed within any given
<Limit> statement. You have three options to specify parse order that give you the ability to override previous deny statements with allow statements, using the order statement
order deny, allow
Using this form lets you, for instance, deny from everywhere, then allow only from a specific domain(s) or host(s), perhaps like this:
<Limit GET> order deny,allow deny from all allow from .corp.adobe.com </Limit>
Likewise, you can override allow statements with deny statements to allow everyone and then deny a few specific domains or hosts like so:
<Limit GET> order allow,deny allow from all deny from .bozo.com </Limit>
You can also treat all connections as denied, unless the host appears in either an allow or deny statement, using the following order option:
<Limit GET> order mutual-failure allow from .metronet.com allow from 130.248 deny from .bozo.com </Limit>
This option is probably the safest, because it won't allow any connections from anywhere, unless they're specifically allowed.
Running our script again now gives the following:
Userid: nobody Group: nogroup Administrator is: [email protected] Running at port: 80 Access filename: .privaccess User Directory: public_html Global Types: text/html .shtml Options for Directory: /usr/local/etc/httpd/cgi-bin Options : None AllowOverride : None Limit: Options for Directory: /usr/local/etc/httpd/htdocs/test1 Options : None AllowOverride : None Limit: GET POST require = valid-user Options for Directory: /usr/local/etc/httpd/htdocs PerlHandler : main::handler AddType : text/html .shtml Options : Indexes SymLinksIfOwnerMatch IncludesNOEXEC AllowOverride : AuthConfig FileInfo Indexes Limit Limit: GET deny = from .bozo.com order = mutual-failure allow = from .metronet.com
But note our
<Limit> directive for
DocumentRoot has not limited retrievals in /cgi-bin. Because the cgi-bin directory isn't beneath
DocumentRoot, it's not affected by the
<Limit> statement. You'll need to explicitly limit anything outside, or above, the directory where you place
<Limit> statements if that is the intent.
Another IP Restriction Mechanism: tcpwrapper
Another alternative, when you wish to restrict/verify connections from particular hosts, is to run a site-wide tool like tcpwrapper. (This will work only if you're starting httpd out of inetd.) You can get tcpwrapper from the COAST archive at
along with plenty of other security tools, papers, and packages. Using tcpwrapper, you can configure certain actions based on the connecting site's domain, or hostname, which are vastly more powerful than the options you have with httpd alone. Many sites out on the open Internet use this tool, and it even ships with a couple of operating systems. If your site has an open pipe to the Internet, it may well be worth investigating this tool.