This directive is only useful for Apache httpd proxy servers within
intranets. The NoProxy directive specifies a
list of subnets, IP addresses, hosts and/or domains, separated by
spaces. A request to a host which matches one or more of these is
always served directly, without forwarding to the configured
ProxyRemote proxy server(s).
- Domain
-
A Domain is a partially qualified DNS domain name, preceded
by a period. It represents a list of hosts which logically belong to the
same DNS domain or zone (i.e., the suffixes of the hostnames are
all ending in Domain).
Examples
.com .example.org.
To distinguish Domains from Hostnames (both syntactically and semantically; a DNS domain can
have a DNS A record, too!), Domains are always written with a
leading period.
Note
Domain name comparisons are done without regard to the case, and
Domains are always assumed to be anchored in the root of the
DNS tree; therefore, the two domains .ExAmple.com and
.example.com. (note the trailing period) are considered
equal. Since a domain comparison does not involve a DNS lookup, it is much
more efficient than subnet comparison.
- SubNet
-
A SubNet is a partially qualified internet address in
numeric (dotted quad) form, optionally followed by a slash and the netmask,
specified as the number of significant bits in the SubNet. It is
used to represent a subnet of hosts which can be reached over a common
network interface. In the absence of the explicit net mask it is assumed
that omitted (or zero valued) trailing digits specify the mask. (In this
case, the netmask can only be multiples of 8 bits wide.) Examples:
-
192.168 or 192.168.0.0
- the subnet 192.168.0.0 with an implied netmask of 16 valid bits
(sometimes used in the netmask form
255.255.0.0 )
-
192.168.112.0/21
- the subnet
192.168.112.0/21 with a netmask of 21
valid bits (also used in the form 255.255.248.0 )
As a degenerate case, a SubNet with 32 valid bits is the
equivalent to an IPAddr, while a SubNet with zero
valid bits (e.g., 0.0.0.0/0) is the same as the constant
_Default_, matching any IP address.
- IPAddr
-
A IPAddr represents a fully qualified internet address in
numeric (dotted quad) form. Usually, this address represents a host, but
there need not necessarily be a DNS domain name connected with the
address.
Example
192.168.123.7
Note
An IPAddr does not need to be resolved by the DNS system, so
it can result in more effective apache performance.
- Hostname
-
A Hostname is a fully qualified DNS domain name which can
be resolved to one or more IPAddrs via the
DNS domain name service. It represents a logical host (in contrast to
Domains, see above) and must be resolvable
to at least one IPAddr (or often to a list
of hosts with different IPAddrs).
Examples
prep.ai.example.edu
www.example.org
Note
In many situations, it is more effective to specify an IPAddr in place of a Hostname since a
DNS lookup can be avoided. Name resolution in Apache httpd can take a remarkable
deal of time when the connection to the name server uses a slow PPP
link.
Hostname comparisons are done without regard to the case,
and Hostnames are always assumed to be anchored in the root
of the DNS tree; therefore, the two hosts WWW.ExAmple.com
and www.example.com. (note the trailing period) are
considered equal.
