DNRD(8) Domain Name Relay Daemon DNRD(8)NAMEdnrd - proxy name server
SYNOPSISdnrd [-a localaddress | --address=localaddress] [-b | --load-balance]
[-B BLACKLIST | --blacklist=BLACKLIST]
[-c (off|[low:]high) | --cache=(off|[low:]high)]
[-d LEVEL | --debug=LEVEL] [-h | --help] [-i | --ignore]
[-k | --kill] [-l | --log] [-m (off|FILE) | --master=(off|FILE)]
[-M N | --max-sock=N] [-r N | --retry=N]
[-R DIR | --dnrd-root=DIR]
[-s ipaddr(:domain) | --server=ipaddr(:domain)]
[-S N[+] | --stats=N[+]] [-t N | --timeout=N]
[-u userid | --uid=userid] [-v | --version]
DESCRIPTIONdnrd is a proxying nameserver. It forwards DNS queries to the
appropriate nameserver, but can also act as the primary nameserver for
a subnet behind a firewall. Proxying is configured on the command line
using the -s option. By default, dnrd will act as the primary
nameserver for hosts found in /usr/local/etc/dnrd/master and queries to
hostnames listed in /usr/local/etc/dnrd/blacklist will be answered with
a "host not found".
OPTIONS-a
--address
Bind only to the interface with the specified address. By
default dnrd binds to everything.
-b
--load-balance
Turn on load balancing. All forward servers (specified with -s)
after this option will load balance in a round robin scheme. By
default, dnrd will use the next server in the list if the first
times out. As soon as the first is reactivated, it will be used
again. With -b option, dnrd will use next active server as soon
a request is served. If a server times out it will be
deactivated and will not be used until it comes back. As soon it
is reactivated it will join the list.
Note that if there are no servers specified with -s after the
-b, this will do nothing at all.
-B BLACKLIST
--blacklist=BLACKLIST
Blacklist all hostnames listed in the file BLACKLIST. Queries to
hosts listed in this file will be answered with "host not
found". The file BLACKLIST is specified relative to the DNRD
chroot directory (defaults to /usr/local/etc/dnrd). By default
dnrd will look for a file named "blacklist".
-c (off|[low:]high)
--cache=(off|[low:]high)
This option can be used to either turn off caching of DNS
responses, or to change the high and low watermarks. With the
high/low water mark option, cached entries are purged when the
number of responses reaches the high-water mark, and they will
be purged until the number of cached responses reaches the
low-water mark, purging the oldest first. By default, caching is
on, with low and high water-marks of 800 and 1000 respectively.
-d LEVEL
--debug=LEVEL
This turns on debugging level LEVEL. The dnrd process will not
fork into the background and print out debugging information in
the current console. Supported debug levels are 1-4 The higher
level, the more debug info is printed.
The -l option can be used to force dnrd to run in the background
and log debug info to syslog.
Sending signal SIGUSR1 will toggle the debug level between level
0 (no debugging) and level 3.
-h
--help Prints usage information
-i
--ignore
Ignore cache for deactivated servers. If a forward DNS server
times out and gets deactivated, all cache entries for this
server are ignored. This helps avoid network timeout delays when
dnrd serves a offline/dialup network.
-k
--kill Kills the currently running dnrd process.
-l
--log Send all messages to syslog. dnrd uses the deamon facility. If
used with the -d flag, this option will cause dnrd to fork and
run in the background, logging all debugging messages to syslog.
-m (off|FILE)
--master=(off|FILE)
dnrd can act as the primary name server for a number of hosts.
By default, it will read in /usr/local/etc/dnrd/master to
determine how this is done. This option specifies another file
than /usr/local/etc/dnrd/master or turns off all primary server
functionality. Sending dnrd signal -HUP will make dnrd try to
re-read the master file unless this is option is set to "off".
Therefore, the master file have to be within the dnrd-root. the
file is specified relative to dnrd-root.
-M N
--max-sock=N
Set the maximum allowed open sockets. Default is 200.
-r N
--retry=N
Set the retry interval time. When a forward DNS server times out
it is deactivated. (use the -t option to set the timeout value)
dnrd will try to send a request for localhost every N seconds.
As soon there are a respose from a deactivated server, it is
reactivated. The default value is 10 seconds. Setting this to
zero will make dnrd to never deactivate a server.
-R DIR
--dnrd-root=DIR
Set the dnrd-root to DIR. dnrd will chroot to this directory at
startup so all files, masterfile and blacklist, must be here.
This option overrides the environment variable DNRD_ROOT.
Default dnrd-root is /usr/local/etc/dnrd.
-s ipaddr(:domain)
--server=ipaddr(:domain)
Add a forward DNS server. If -s is used multiple times, the
first is the primary DNS server and the rest are backup servers.
If the primary DNS server times out, it is deactivated and the
next specified server (that is active) is used until the
previous gets reactivated.
The domain option allows dnrd to determine which DNS server
should get the query based on the domain name in the query. This
is useful when you have an internet connection and a vpn
connection to work, for instance. Several servers with the same
domain might be specified and then will they work as backup
servers.
If the -b option is specified, then all servers specified after
the -b option are load balanced per domain.
-S N[+]
--stats=N[+]
Print statistics about cache hits, cache misses and timeouts to
syslog every N seconds. If + is specified, the counters will
not be reset after the print.
-t N
--timeout=N
Set the timeout value for forward DNS servers. If a server don't
respond to a query within N seconds it is deactivated. The
default value is 12
Setting this to zero will make dnrd to never deactivate a server
because of timeouts. However, a server might be deactivated if
sendto fails.
-u userid
--userid=userid
Set the UID that dnrd will run as. By default, dnrd tries to
switches to uid dnrd after starting up.
-v
--version
Prints out the version number.
BUGS
The TTL's are not respected for the cache.
FILES
/usr/local/etc/dnrd/master
This file is used to configure dnrd as a primary nameserver.
/usr/local/etc/dnrd/blacklist
Hosts listed in this file are blacklisted.
/var/run/dnrd.pid
The currently-running dnrd process' pid is placed into this file. It is
needed to allow new dnrd processes to find and kill the currently
running process.
AUTHOR
The original version of dnrd was written by Brad Garcia garsh@home.com.
Other contributors are listed in the HISTORY file included with the
source code.
DNRD v2.20 Domain Name Relay Daemon DNRD(8)
