OPTIONS
    Original: Paul Vixie, 28Mar92
    Revised: $Id: OPTIONS,v 8.5 1995/12/29 21:08:13 vixie Exp $

Options available in this version of BIND are controlled by conf/options.h,
rather than by $(DEFS) in the Makefile.  The options are:

DEBUG (origin: U C Berkeley)
	enables the -d command line option, and allows SIGUSR1 to increment
and SIGUSR2 to clear the internal variable "debug", which in turn controls
hundreds of fprintf()'s out to /usr/tmp/named.run.
	you probably want this.  it makes the binary bigger but not slower (or
at least not much slower), but SIGUSR[12] are the only way you'll track down
misconfigured name servers that hose you down with billions of bogus requests.
	you may need this, it is on by default.

ALLOW_T_UNSPEC (origin: MIT Project Athena)
	enables the "unspec" RR type for ancient Athena software that does not
know about TXT RR's.
	you probably do not care about this, it is off by default.

ALLOW_UPDATES (origin: Mike Schwartz, University of Washington)
	enables "dynamic updates", described in "doc/DynamicUpdate".  this lets
you update named's in-memory database on the fly if you have the right client.
there is absolutely no security around this; if you enable it, anyone who can
reach your server can update your database.
	this code doesn't compile any more and will be removed shortly.

INVQ (origin: U C Berkeley, with #ifdef's by Paul Vixie)
	enables "inverse queries", which in all of the internet only one
client ever uses: ancient nslookup.  if you build named with INVQ defined,
you get the time-honored behaviour of supporting this whole class of queries
for no real purpose other than to waste a few hundred kilobytes of your
memory and about 3% of named's total CPU time.  if you build with INVQ
undefined, old nslookups will not be able to reach your server in their
startup phase, and you will have to use the "server" command after it fails
over to some other server, or use "nslookup - 0" to get in from the shell.
	you probably do not want this.

DSTORAGE (origin: U C Berkeley, with #ifdef's by Paul Vixie)
	enables a malloc-debugger that checks for overruns on both ends of
each allocated block of memory.  used when debugging since C has no bounds
or type checking.
	you probably do not want this, it is off by default.

DMALLOC (origin: Paul Vixie of Digital)
	enables a malloc-debugger that traces all allocated blocks of memory
such that SIGIOT's output (see STATS option) includes a list of all mallocs
in the program, how many times each has been called, how many blocks of memory
allocated by that malloc are not yet free, and how many bytes they use up.
under each one will be a list of each free/realloc that has deallocated a block
of that malloc's memory, and how many times it has done so.
	this is extremely helpful for finding memory leaks.  as such, you
probably do not want this unless you are debugging named.
	you probably do not need this, it is off by default.

XFRNETS (origin: Paul Vixie of Digital)
	enables the "xfrnets" command in named.boot.  this has the same
syntax as "forwarders" and "sortlist" -- that is, a list of dotted quads.
each one is a network (16.0.0.0 and 130.180.0.0 are examples) or a host.
if you put any xfrnets commands into your named.boot, then zone transfers
will only be honored if they come from inside one of the specified
networks.  this is very useful if you want to keep people outside from
being able to trivially map your entire network, but it doesn't stop them
from iterating so it's more annoying than secure.
	this feature was once called "tcplist" out of ignorance on my part,
but with advice from phil almquist i decided to rename it "xfrnets" and make
it only control zone transfers -- previously it controlled all TCP connections
which made certain TCP-only resolvers unable to use our servers.  the "tcplist"
syntax still works; it is a synonym for "xfrnets".
	it is also nice if you want to keep the outside world from making your
nameserver fork and swap trying to do unauthorized zone transfers. if you have 
large zone files or use BIND for TXT records you will find this useful.
	you probably want this, it is on by default.

PID_FIX (origin: Don Lewis of Harris)
	tells named that if it starts up but can't keep going because another
nameserver is already running (and sitting on the server port), it should
put the /etc/named.pid (/var/run/named.pid) file back the way it found it.
	you probably want this, it is on by default.

FWD_LOOP (origin: Don Lewis of Harris)
	tells named that if you list any of your own IP addresses in a
"forwarders" command in your named.boot file, you should be scolded.
	you probably want this, it is on by default.

NO_GLUE (origin: Don Lewis of Harris, and Andrew Partan of UUNET)
	tells named-xfer that incoming zone transfers should be checked
for "glue" that comes from a zone outside the zone being transfered, and
comment this garbage out in the zone file so that when named reads in the
zone file after named-xfer exits, the garbage will not be entered into the
memory-resident database.
	also tells named that when it is performing an outgoing zone
transfer, it should not send any of these "glue" records.
	you definitely want this, it is on by default.

BOGUSNS (origin: Piet Beertema of EUNet)
	enables the "bogusns" command in named.boot.  this has the same
syntax as forwarders and sortlist.  any NS RR's that come in whose addresses
are on the list of "bogusns" addresses will be ignored.  this is the last
resort when someone is bogusly advertising themselves as a root server.
	just in case, though you won't use it often.
	you probably want this, it is on by default.

QRYLOG (origin: Bryan Beecher of UMich)
	enables "query logging", such that SIGWINCH toggles tracing of all
incoming queries.  the trace is sent to syslog, and is huge, but when you
need this you will need it bad and it does not slow named down or make it
larger.
	If you define QRYLOG you may also start up named in query logging
mode by using the -q flag.  If you do so you will probably want to analyze
the logs produced, the dnsstats and lamers scrips (in the contrib/umich
and contrib/lamers directories) will do it for you.
	you probably want this, it is on by default.

LOGFAC (origin: various people)
	If you start up named with the -q flag you will be logging
large amounts of data, and probably will not want them logged to the
default logging facility, which is LOG_DAEMON.  You will want to
redefine LOGFAC, presumably to LOC_LOCALn (0 <= n <= 7).  Remember to
modify /etc/syslog.conf appropriately.
	This only works on a system with a modern syslogd.
	as such, it is on by default.

YPKLUDGE (origin: Piet Beertema of EUNet)
	certain versions of NIS/YP are capable of using the DNS for names
that cannot be found in the YP servers.  of these, certain versions can't
tell the difference between a dotted quad and a domain name, and they send
queries to the DNS for dotted quads as if they were domain names.  if your
named does not do anything special with these queries, they will end up
getting forwarded to other servers, effectively hosing all of you down with
endless useless network traffic.  YPKLUDGE enables some checking in named
that lets it catch these bogus queries and send back immediate errors.
	If you run "ypserv -i" you definitely want this, as a malconfigured
NIS server can cause DNS "flood" queries otherwise. Trust me.
	this is off by default.

TRACEROOT (origin: pma@cnd.hp.com and Bryan Beecher of UMich)
	enables some checking in named for bogus root nameservers.  This
code has been in use at U-M for years, so it is pretty well tested, plus we
have never been burned by the "bogus root NS scares" that have plagued the
DNS off and on.
	this feature people will very much want to use, it is on by default.

LOCALDOM (origin: Berkeley)
	if set, the "domain" directive is recognized in the named.boot file.
this causes us to retry queries with the specified domain appended to the
name if the first lookup fails.  this is a very bad idea since a given name
server will often be used by clients in more than one domain -- a name server
should _not_ make any presumptions as to the "home domain" of a requestor.
	you almost certainly do not want this, it is off by default.

SLAVE_FORWARD (origin: pma@sdd.hp.com)
	if set, "slave" servers behave in an arguably more-correct way.  this
is an experimental addition to BIND 4.9 that causes slaves to time out queries
in 60/N seconds where N is the number of forwarders defined.  previously a
query would time out almost immediately, which caused a lot of unnecessary
network traffic.
	you probably want this, it is on by default.

FORCED_RELOAD (origin: pma@sdd.hp.com)
	if set, then when a HUP signal is received, all secondary zones are
scheduled for serial-number comparison with the primaries.  this has the effect
that if you HUP your server, it will refresh any zones which have changed,
even if those zones' refresh times have not been reached.
	you probably want this, it is on by default.

WANT_PIDFILE (origin: berkeley, parameterized by arc@sgi)
	if set, a file called named.pid will be created in /etc or /var/run
when the name server has started.  this file can be used to send signals to
BIND, as in "kill -HUP `cat /etc/named.pid`".
	unless you are only on an SGI (where killall(1M) makes the pid file 
unnecessary); 
	you probably want this, it is on by default.

DOTTED_SERIAL (origin: berkeley; parameterized by vixie)
	if set, allows a somewhat arcane n.m syntax in the serial number
field of an SOA.  this is officially deprecated for 4.9; you should use
straight integer values and find an encoding that does not depend on 
scaled-integer pseudodecimals.  i suggest YYYYMMDDnn where YYYY is the
four-digit year, MM is the two-digit month, DD is the two-digit day-of-month,
and nn is a daily version number in case you change your serial number more
than once in a day.  this encoding will overflow in the year 4294 gregorian.
	you almost certainly do not want this, but if you have old zone files
lying around and you don't want to think your way through converting their
serial numbers, this deprecated behaviour is available.
	graciously, it is on by default.

SENSIBLE_DOTS (origin: kagotani@cs.titech.ac.jp; parameterized by vixie)
	if set, changes the semantics of an "n.m" serial number from
		n*10^(3+int(0.9+log10(m))) + m
to
		n*10000+m
	if you are using DOTTED_SERIAL in spite of its deprecated status,
and you are interested in a more predictable and sensible interpretation of
dotted numbers, then you probably want this.
	it is off by default.

VALIDATE (origin: USC/ISI)
	enables a validation procedure to provide some security in an
otherwise insecure environment. Any RRs are accepted from a server only if
the server is authoritative over that domain. We consider a server
authoritative (for validation purposes) for even the sub-domains that it has
delegated to others. RRs are validated against the data we have in cache
already. Invalid records are neither cached nor returned.
	it is off by default because it is hopeless, and the code will all
be ripped out of BIND in the near future.

NCACHE (origin: USC/ISI)
	enables negative caching. We cache only authoritative NXDOMAIN or
authoritative NOERROR with zero RR count. Non-authoritative NXDOMAIN answers
now contain NS records in the authority section. Non-authoritative NOERROR
responses have no authority or additional records to differentiate them from
referrals. They are cached for NTTL secs (currently 10 minutes) and are timed
out when the ttl expires.
	you probably want this, it is on by default.

RESOLVSORT (origin: marka@syd.dms.csiro.au)
	enable sorting of addresses returned by gethostbyname. Sorting order
is specified by address/netmask pairs. This enables a host to override the
sortlist specified in the nameserver.
	you probably want this, it is on by default.

STUBS (origin: marka@syd.dms.csiro.au)
	enable transfer and loading of NS records only for a zone.
still experimental. it won't hurt to enable it, but it may not work perfectly 
so using it could lead to some confusion.  
	you probably don't care, it is on by default.

SUNSECURITY (origin: rossc@ucc.su.oz.au)
  	enable checking of PTR records in gethostbyaddr() to detect
spoofing.  Forced on SunOS 4 shared library as rlogin etc. depend on this.
	you should probably not set this by hand.

SECURE_ZONES (origin: gshapiro@guest.wpi.edu)
	enables support for secure zones.  This restricts access to
information in the zone according to the information found in the
secure_zone TXT RR found in the zone.  If none is found, the zone is
world-readable.  For information on the format of the secure_zone TXT
RR, see the Name Server Operations Guide for BIND.
	you probably want this, it is on by default.

ROUND_ROBIN (origin: Marshall Rose of TPC.INT)
	if set, causes the databuf list in a namebuf to be rotated by one
slot after each access to it.  this has the effect that if multiple RR's
of a given type are present, they will be given in "round robin" order 
instead of always being given in the same order.
	you probably want this, it is on by default.

ADDAUTH (origin: marka@syd.dms.csiro.au)
	if set, cause NS and glue A records to be returned with authoritative
answers.  this causes slightly larger replies but less DNS traffic overall.
	unless you have Mac's with an older version of Mac/TCP;
	you probably want this, it is on by default.

RFC1535 (origin: paul@vix.com)
	if set, the resolver's default "search" list will be just the entire
"domain" name rather than the sliding window it had before 4.9.2.  this will
make the default search list shorter, so folks who are saying "domain a.b.c"
and relying on the implicit "search a.b.c a.b c" will miss "a.b" and "c".
	this option is on for compatibility with RFC 1535.  
	you should NOT turn it off, it is on by default.

GEN_AXFR (origin: mark@comp.vuw.ac.nz, tytso@ATHENA.MIT.EDU, gdmr@dcs.ed.ac.uk)
	if set, allows specification of zones in classes other than "IN" in
the named.boot file. Allows an optional "/class" on the "primary" and
"secondary" directives.  Also fixes zone transfers so only data in the class
requested is transfered.
	you probably want this, it is on by default.

DATUMREFCNT (origin: mark andrews)
	you want this.  it will not be optional in future releases.

LAME_DELEGATION (origin: don lewis; reworked by bryan beecher and don lewis)
	this will detect the condition where some other server has told you 
that a given set of servers is authoritative for some domain, and at least 
one of those "delegated" servers disagrees (i.e., answers non-authoritatively).
	you probably want this, it is on by default.

LAME_LOGGING (origin: don lewis)
	enable logging of lame delegations and set the log level
	you may want this, it is on by default.

RETURNSOA (origin: mark andrews)
	This allows negative caching to work. Without this, older
pre-4.9.3 nameservers will not accept -ve cached anwsers.  We actually
store the SOA record from the authority section rather that what was
requested because it is the existence of the NXDOMAIN that matters not
the type of data. The zone of the SOA record is tagged to the end of
the SOA record to allow it to be reconstructed.
	You probably DO NOT WANT THIS, it's experimental and dangerous.
	it is off by default.

CLEANCACHE (origin: mark andrews)
	Bind consumes memory without bound without this option. This
patch allows bind to periodically remove any stale entries in the
cache.  Bind's memory usage should stabilize after approximately 1 day of
operation, as most TTL's are <= 1 day. Without this option stale entries
are only removed when they are looked up.
	You probably want this, it is on by default.

PURGE_ZONE (origin: mark andrews)
	Various junk below a zone tends to hang around and corrupt future
zone data if a zone grows deeper.  PURGE_ZONE will remove all traces of or
data which could be part of zone before loading a new one.
	You probably want this, it is on by default.

STATS (origin: Paul Vixie)
	Named's internal statistics can take a fair amount of memory and
if you aren't interested in looking at these numbers you should disable
the feature. Future versions may require this.
	You probably want this, it is on by default.

RENICE (origin: bp@deins.informatik.uni-dortmund.de)
	if set, the process priority of the AXFR subprocesses is changed to
"normal". If you are planning to raise the priority of the main nameserver
process, you will use this.
	You probably want this, it is on by default.

GETSER_LOGGING (origin: Paul Vixie)
	if set, errors that occur during the fetch of serial numbers for zone
transfer consideration will be syslog()'d.  this can lead to a lot of logging,
but is very helpful if you don't know why a zone isn't transfering.
	You may not want this, but it is on by default.

SHORT_FNAMES (origin: pma@sdd.hp.com)
	on systems whose file names can only be 14 characters long, the temp
files created by named-xfer need to be constructed somewhat differently.  this
should probably become the default since it is harmless.
	you probably don't care one way or the other, it is off by default.

XSTATS (origin: Benoit.Grange@inria.fr)
	if set, the name server keeps more STATS about requests
received, and logs to syslog total counters from time to time. If you
aren't interested in looking at these numbers you should disable the
feature. Requires STATS.
	You may want this, it is on by default.

BIND_NOTIFY (origin: paul@vix.com)
	experimental at this time; an internet draft is circulating.  this
option informs slaves ("secondary" servers in BIND's erroneous terminology)
instantly when the master (primary, or another slave) loads a new zone.  it
works fine and seems to cause no problems with slaves that don't support it,
but it does not implement the current internet draft (it lacks some necessary
delays) and causes a lot of extra syslog traffic, especially at startup.  if
you don't mind running code that will absolutely NOT be compatible with the
eventual standard when the RFC is released, go ahead and turn this on.
	vendors should not enable this in versions shipped to customers.
	You will want this when it becomes compliant, it is off by default.

LOC_RR (origin: ckd@kei.com)
        incorporates support for the LOC RR type, currently in the
internet-draft stage.
        you don't want this yet, it is off by default.

SORT_RESPONSE (legacy)
	should responses be sorted in what the server considers an optimal
order for the client?  this is on by default but it does very little good.

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