mirror of
https://gitlab.isc.org/isc-projects/bind9
synced 2025-08-31 14:35:26 +00:00
reviewed and edited; removed lwres intro material
that is better covered in lwres(3)
This commit is contained in:
Andreas Gustafsson
@@ -14,7 +14,7 @@
|
||||
.\" NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION
|
||||
.\" WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
|
||||
.\"
|
||||
.\" $Id: lwresd.8,v 1.3 2000/07/12 19:39:49 tale Exp $
|
||||
.\" $Id: lwresd.8,v 1.4 2000/07/17 17:49:25 gson Exp $
|
||||
.\"
|
||||
.Dd Jun 30, 2000
|
||||
.Dt LWRESD 8
|
||||
@@ -36,22 +36,15 @@
|
||||
.Op Fl u Ar user-id
|
||||
.Sh DESCRIPTION
|
||||
.Nm lwresd
|
||||
is the daemon for processes that use the BIND 9 lightweight resolver
|
||||
library.
|
||||
The daemon is actually a DNS name server,
|
||||
.Nm named ,
|
||||
though when it operates as the lightweight resolver server
|
||||
.Nm lwresd ,
|
||||
it is functionally and logically distinct from an actual name server.
|
||||
It does not handle conventional DNS lookups in the wire format defined
|
||||
in RFC1035 or listen for queries on the default name server port number.
|
||||
.Nm lwresd
|
||||
only handles requests that are in the canonical
|
||||
format for the lightweight resolver protocol.
|
||||
is the daemon providing name lookup services to clients that use
|
||||
the BIND 9 lightweight resolver library.
|
||||
It is essentially a stripped-down, caching-only name server that
|
||||
answers queries using the BIND 9 lightweight resolver protocol
|
||||
rather than the DNS protocol.
|
||||
.Pp
|
||||
When listening for lightweight resolver queries,
|
||||
.Nm lwresd
|
||||
uses a UDP port on the IPv4 loopback interface, 127.0.0.1.
|
||||
listens for resolver queries on a UDP port on the IPv4 loopback
|
||||
interface, 127.0.0.1.
|
||||
This means that
|
||||
.Nm lwresd
|
||||
can only be used by processes running on the local machine.
|
||||
@@ -67,40 +60,21 @@ encodes the answers from the name servers in the lightweight
|
||||
resolver format and returns them to the client that made the original
|
||||
request.
|
||||
.Pp
|
||||
The lightweight resolver daemon is comparable to a forwarding name server
|
||||
except that it receives requests in the lightweight resolver format
|
||||
rather than conventional DNS queries.
|
||||
It reads
|
||||
If
|
||||
.Pa /etc/resolv.conf
|
||||
and uses the
|
||||
contains any
|
||||
.Sy nameserver
|
||||
entries to determine which IP addresses to use when making DNS
|
||||
lookups.
|
||||
If no
|
||||
.Pa /etc/resolv.conf
|
||||
is present,
|
||||
entries,
|
||||
.Nm lwresd
|
||||
uses its built-in list of root name servers.
|
||||
In this mode of operation,
|
||||
sends recursive DNS queries to those servers. This
|
||||
is similar to the use of forwarders in a chaching name
|
||||
server. If no
|
||||
.Sy nameserver
|
||||
entries are present, or if forwarding fails,
|
||||
.Nm lwresd
|
||||
analogous to a caching-only name server, albeit one that does not
|
||||
receive conventional DNS queries.
|
||||
.Pp
|
||||
The lightweight resolver simplifies the task of looking up hostnames
|
||||
or IP addresses in the DNS.
|
||||
Clients construct simple questions like \*qwhat is the hostname for
|
||||
the following address?\*q or \*qwhat are the addresses of hostname
|
||||
.Dv host.example.com?\*q and send them to
|
||||
.Nm lwresd .
|
||||
This saves them from a number of possible complications and perhaps
|
||||
having to make many DNS queries to resolve the hostname or IP address.
|
||||
Without the lightweight resolver, clients would be expected to deal
|
||||
with the complexities of
|
||||
processing the DNS resource records used for IPv6 addresses, dealing
|
||||
with DNAME records and deciphering DNSSEC.
|
||||
Instead of directly handling those complications, clients can make
|
||||
.Nm lwresd
|
||||
do the work for them.
|
||||
resolves the queries autonomously starting at the
|
||||
root name servers, using a compiled-in list of root
|
||||
servers hints.
|
||||
.Pp
|
||||
The options to
|
||||
.Nm lwresd
|
||||
@@ -122,23 +96,25 @@ run
|
||||
.Nm lwresd
|
||||
in the foreground.
|
||||
.It Fl g
|
||||
also runs the lightweight resolver daemon in the foreground, but
|
||||
logs to
|
||||
run
|
||||
.Nm lwresd
|
||||
in the foreground and force all logging to
|
||||
.Dv stderr .
|
||||
.It Fl i
|
||||
write the daemon's process id to
|
||||
.Ar pid-file
|
||||
instead of the default pathname.
|
||||
.It Fl n
|
||||
create threads that use
|
||||
create
|
||||
.Ar #cpus
|
||||
CPUs if the hardware and software permits this.
|
||||
When
|
||||
.Ar #cpus
|
||||
is set to zero,
|
||||
worker threads to take advantage of multiple CPUs.
|
||||
If no option is given,
|
||||
.Nm lwresd
|
||||
will try to determine the number of CPUs present and use 1 if this
|
||||
attempt fails.
|
||||
will try to determine the number of CPUs present and create
|
||||
one thread per CPU. If
|
||||
.Nm lwresd
|
||||
is unable to determine the number of CPUs, a single worker thread
|
||||
is created.
|
||||
.It Fl P
|
||||
send DNS lookups to port number
|
||||
.Ar query-port#
|
||||
|
||||
@@ -14,7 +14,7 @@
|
||||
.\" NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION
|
||||
.\" WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
|
||||
.\"
|
||||
.\" $Id: lwresd.8,v 1.3 2000/07/12 19:39:49 tale Exp $
|
||||
.\" $Id: lwresd.8,v 1.4 2000/07/17 17:49:25 gson Exp $
|
||||
.\"
|
||||
.Dd Jun 30, 2000
|
||||
.Dt LWRESD 8
|
||||
@@ -36,22 +36,15 @@
|
||||
.Op Fl u Ar user-id
|
||||
.Sh DESCRIPTION
|
||||
.Nm lwresd
|
||||
is the daemon for processes that use the BIND 9 lightweight resolver
|
||||
library.
|
||||
The daemon is actually a DNS name server,
|
||||
.Nm named ,
|
||||
though when it operates as the lightweight resolver server
|
||||
.Nm lwresd ,
|
||||
it is functionally and logically distinct from an actual name server.
|
||||
It does not handle conventional DNS lookups in the wire format defined
|
||||
in RFC1035 or listen for queries on the default name server port number.
|
||||
.Nm lwresd
|
||||
only handles requests that are in the canonical
|
||||
format for the lightweight resolver protocol.
|
||||
is the daemon providing name lookup services to clients that use
|
||||
the BIND 9 lightweight resolver library.
|
||||
It is essentially a stripped-down, caching-only name server that
|
||||
answers queries using the BIND 9 lightweight resolver protocol
|
||||
rather than the DNS protocol.
|
||||
.Pp
|
||||
When listening for lightweight resolver queries,
|
||||
.Nm lwresd
|
||||
uses a UDP port on the IPv4 loopback interface, 127.0.0.1.
|
||||
listens for resolver queries on a UDP port on the IPv4 loopback
|
||||
interface, 127.0.0.1.
|
||||
This means that
|
||||
.Nm lwresd
|
||||
can only be used by processes running on the local machine.
|
||||
@@ -67,40 +60,21 @@ encodes the answers from the name servers in the lightweight
|
||||
resolver format and returns them to the client that made the original
|
||||
request.
|
||||
.Pp
|
||||
The lightweight resolver daemon is comparable to a forwarding name server
|
||||
except that it receives requests in the lightweight resolver format
|
||||
rather than conventional DNS queries.
|
||||
It reads
|
||||
If
|
||||
.Pa /etc/resolv.conf
|
||||
and uses the
|
||||
contains any
|
||||
.Sy nameserver
|
||||
entries to determine which IP addresses to use when making DNS
|
||||
lookups.
|
||||
If no
|
||||
.Pa /etc/resolv.conf
|
||||
is present,
|
||||
entries,
|
||||
.Nm lwresd
|
||||
uses its built-in list of root name servers.
|
||||
In this mode of operation,
|
||||
sends recursive DNS queries to those servers. This
|
||||
is similar to the use of forwarders in a chaching name
|
||||
server. If no
|
||||
.Sy nameserver
|
||||
entries are present, or if forwarding fails,
|
||||
.Nm lwresd
|
||||
analogous to a caching-only name server, albeit one that does not
|
||||
receive conventional DNS queries.
|
||||
.Pp
|
||||
The lightweight resolver simplifies the task of looking up hostnames
|
||||
or IP addresses in the DNS.
|
||||
Clients construct simple questions like \*qwhat is the hostname for
|
||||
the following address?\*q or \*qwhat are the addresses of hostname
|
||||
.Dv host.example.com?\*q and send them to
|
||||
.Nm lwresd .
|
||||
This saves them from a number of possible complications and perhaps
|
||||
having to make many DNS queries to resolve the hostname or IP address.
|
||||
Without the lightweight resolver, clients would be expected to deal
|
||||
with the complexities of
|
||||
processing the DNS resource records used for IPv6 addresses, dealing
|
||||
with DNAME records and deciphering DNSSEC.
|
||||
Instead of directly handling those complications, clients can make
|
||||
.Nm lwresd
|
||||
do the work for them.
|
||||
resolves the queries autonomously starting at the
|
||||
root name servers, using a compiled-in list of root
|
||||
servers hints.
|
||||
.Pp
|
||||
The options to
|
||||
.Nm lwresd
|
||||
@@ -122,23 +96,25 @@ run
|
||||
.Nm lwresd
|
||||
in the foreground.
|
||||
.It Fl g
|
||||
also runs the lightweight resolver daemon in the foreground, but
|
||||
logs to
|
||||
run
|
||||
.Nm lwresd
|
||||
in the foreground and force all logging to
|
||||
.Dv stderr .
|
||||
.It Fl i
|
||||
write the daemon's process id to
|
||||
.Ar pid-file
|
||||
instead of the default pathname.
|
||||
.It Fl n
|
||||
create threads that use
|
||||
create
|
||||
.Ar #cpus
|
||||
CPUs if the hardware and software permits this.
|
||||
When
|
||||
.Ar #cpus
|
||||
is set to zero,
|
||||
worker threads to take advantage of multiple CPUs.
|
||||
If no option is given,
|
||||
.Nm lwresd
|
||||
will try to determine the number of CPUs present and use 1 if this
|
||||
attempt fails.
|
||||
will try to determine the number of CPUs present and create
|
||||
one thread per CPU. If
|
||||
.Nm lwresd
|
||||
is unable to determine the number of CPUs, a single worker thread
|
||||
is created.
|
||||
.It Fl P
|
||||
send DNS lookups to port number
|
||||
.Ar query-port#
|
||||
|
||||
Reference in New Issue
Block a user