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authorJakob Schlyter <jakob@cvs.openbsd.org>2007-12-09 13:39:46 +0000
committerJakob Schlyter <jakob@cvs.openbsd.org>2007-12-09 13:39:46 +0000
commit1173d5eff8dc423c129f442023419436ee94db23 (patch)
tree57c2bcdc1429b2e80b91a387cd1dc561dab988eb /usr.sbin/bind/FAQ
parente4a92ccc5f8c866478b32a346c71150a2cdf5001 (diff)
resolve conflicts
Diffstat (limited to 'usr.sbin/bind/FAQ')
-rw-r--r--usr.sbin/bind/FAQ822
1 files changed, 464 insertions, 358 deletions
diff --git a/usr.sbin/bind/FAQ b/usr.sbin/bind/FAQ
index ba87de21652..90b3ca04538 100644
--- a/usr.sbin/bind/FAQ
+++ b/usr.sbin/bind/FAQ
@@ -4,97 +4,71 @@ Copyright © 2004-2007 Internet Systems Consortium, Inc. ("ISC")
Copyright © 2000-2003 Internet Software Consortium.
--------------------------------------------------------------------------------
+-----------------------------------------------------------------------
-Q: Why doesn't -u work on Linux 2.2.x when I build with --enable-threads?
+1. Compilation and Installation Questions
-A: Linux threads do not fully implement the Posix threads (pthreads) standard. In
- particular, setuid() operates only on the current thread, not the full process.
- Because of this limitation, BIND 9 cannot use setuid() on Linux as it can on
- all other supported platforms. setuid() cannot be called before creating
- threads, since the server does not start listening on reserved ports until
- after threads have started.
+Q: I'm trying to compile BIND 9, and "make" is failing due to files not
+ being found. Why?
- In the 2.2.18 or 2.3.99-pre3 and newer kernels, the ability to preserve
- capabilities across a setuid() call is present. This allows BIND 9 to call
- setuid() early, while retaining the ability to bind reserved ports. This is a
- Linux-specific hack.
+A: Using a parallel or distributed "make" to build BIND 9 is not
+ supported, and doesn't work. If you are using one of these, use normal
+ make or gmake instead.
- On a 2.2 kernel, BIND 9 does drop many root privileges, so it should be less of
- a security risk than a root process that has not dropped privileges.
+Q: Isn't "make install" supposed to generate a default named.conf?
- If Linux threads ever work correctly, this restriction will go away.
+A: Short Answer: No.
- Configuring BIND9 with the --disable-threads option (the default) causes a
- non-threaded version to be built, which will allow -u to be used.
+ Long Answer: There really isn't a default configuration which fits any
+ site perfectly. There are lots of decisions that need to be made and
+ there is no consensus on what the defaults should be. For example
+ FreeBSD uses /etc/namedb as the location where the configuration files
+ for named are stored. Others use /var/named.
-Q: Why do I get the following errors:
+ What addresses to listen on? For a laptop on the move a lot you may
+ only want to listen on the loop back interfaces.
- general: errno2result.c:109: unexpected error:
- general: unable to convert errno to isc_result: 14: Bad address
- client: UDP client handler shutting down due to fatal receive error: unexpected error
+ Who do you offer recursive service to? Is there are firewall to
+ consider? If so is it stateless or stateful. Are you directly on the
+ Internet? Are you on a private network? Are you on a NAT'd network? The
+ answers to all these questions change how you configure even a caching
+ name server.
-A: This is the result of a Linux kernel bug.
-
- See: http://marc.theaimsgroup.com/?l=linux-netdev&m=113081708031466&w=2
+2. Configuration and Setup Questions
-Q: Why does named log the warning message "no TTL specified - using SOA MINTTL
- instead"?
+Q: Why does named log the warning message "no TTL specified - using SOA
+ MINTTL instead"?
-A: Your zone file is illegal according to RFC1035. It must either have a line
- like:
+A: Your zone file is illegal according to RFC1035. It must either have a
+ line like:
$TTL 86400
- at the beginning, or the first record in it must have a TTL field, like the
- "84600" in this example:
+ at the beginning, or the first record in it must have a TTL field, like
+ the "84600" in this example:
example.com. 86400 IN SOA ns hostmaster ( 1 3600 1800 1814400 3600 )
-Q: Why do I see 5 (or more) copies of named on Linux?
-
-A: Linux threads each show up as a process under ps. The approximate number of
- threads running is n+4, where n is the number of CPUs. Note that the amount of
- memory used is not cumulative; if each process is using 10M of memory, only a
- total of 10M is used.
-
- Newer versions of Linux's ps command hide the individual threads and require -L
- to display them.
-
-Q: Why does BIND 9 log "permission denied" errors accessing its configuration
- files or zones on my Linux system even though it is running as root?
-
-A: On Linux, BIND 9 drops most of its root privileges on startup. This including
- the privilege to open files owned by other users. Therefore, if the server is
- running as root, the configuration files and zone files should also be owned by
- root.
-
-Q: Why do I get errors like "dns_zone_load: zone foo/IN: loading master file bar:
- ran out of space"?
+Q: Why do I get errors like "dns_zone_load: zone foo/IN: loading master
+ file bar: ran out of space"?
-A: This is often caused by TXT records with missing close quotes. Check that all
- TXT records containing quoted strings have both open and close quotes.
-
-Q: How do I produce a usable core file from a multithreaded named on Linux?
-
-A: If the Linux kernel is 2.4.7 or newer, multithreaded core dumps are usable
- (that is, the correct thread is dumped). Otherwise, if using a 2.2 kernel,
- apply the kernel patch found in contrib/linux/coredump-patch and rebuild the
- kernel. This patch will cause multithreaded programs to dump the correct
- thread.
+A: This is often caused by TXT records with missing close quotes. Check
+ that all TXT records containing quoted strings have both open and close
+ quotes.
Q: How do I restrict people from looking up the server version?
-A: Put a "version" option containing something other than the real version in the
- "options" section of named.conf. Note doing this will not prevent attacks and
- may impede people trying to diagnose problems with your server. Also it is
- possible to "fingerprint" nameservers to determine their version.
+A: Put a "version" option containing something other than the real version
+ in the "options" section of named.conf. Note doing this will not
+ prevent attacks and may impede people trying to diagnose problems with
+ your server. Also it is possible to "fingerprint" nameservers to
+ determine their version.
Q: How do I restrict only remote users from looking up the server version?
-A: The following view statement will intercept lookups as the internal view that
- holds the version information will be matched last. The caveats of the previous
- answer still apply, of course.
+A: The following view statement will intercept lookups as the internal
+ view that holds the version information will be matched last. The
+ caveats of the previous answer still apply, of course.
view "chaos" chaos {
match-clients { <those to be refused>; };
@@ -105,120 +79,46 @@ A: The following view statement will intercept lookups as the internal view that
};
};
-Q: What do "no source of entropy found" or "could not open entropy source foo"
- mean?
-
-A: The server requires a source of entropy to perform certain operations, mostly
- DNSSEC related. These messages indicate that you have no source of entropy. On
- systems with /dev/random or an equivalent, it is used by default. A source of
- entropy can also be defined using the random-device option in named.conf.
-
-Q: I installed BIND 9 and restarted named, but it's still BIND 8. Why?
-
-A: BIND 9 is installed under /usr/local by default. BIND 8 is often installed
- under /usr. Check that the correct named is running.
-
-Q: I'm trying to use TSIG to authenticate dynamic updates or zone transfers. I'm
- sure I have the keys set up correctly, but the server is rejecting the TSIG.
- Why?
-
-A: This may be a clock skew problem. Check that the the clocks on the client and
- server are properly synchronised (e.g., using ntp).
-
-Q: I'm trying to compile BIND 9, and "make" is failing due to files not being
- found. Why?
-
-A: Using a parallel or distributed "make" to build BIND 9 is not supported, and
- doesn't work. If you are using one of these, use normal make or gmake instead.
-
-Q: I have a BIND 9 master and a BIND 8.2.3 slave, and the master is logging error
- messages like "notify to 10.0.0.1#53 failed: unexpected end of input". What's
- wrong?
-
-A: This error message is caused by a known bug in BIND 8.2.3 and is fixed in BIND
- 8.2.4. It can be safely ignored - the notify has been acted on by the slave
- despite the error message.
+Q: What do "no source of entropy found" or "could not open entropy source
+ foo" mean?
-Q: I keep getting log messages like the following. Why?
-
- Dec 4 23:47:59 client 10.0.0.1#1355: updating zone 'example.com/IN': update
- failed: 'RRset exists (value dependent)' prerequisite not satisfied (NXRRSET)
+A: The server requires a source of entropy to perform certain operations,
+ mostly DNSSEC related. These messages indicate that you have no source
+ of entropy. On systems with /dev/random or an equivalent, it is used by
+ default. A source of entropy can also be defined using the
+ random-device option in named.conf.
-A: DNS updates allow the update request to test to see if certain conditions are
- met prior to proceeding with the update. The message above is saying that
- conditions were not met and the update is not proceeding. See doc/rfc/
- rfc2136.txt for more details on prerequisites.
+Q: I'm trying to use TSIG to authenticate dynamic updates or zone
+ transfers. I'm sure I have the keys set up correctly, but the server is
+ rejecting the TSIG. Why?
-Q: I keep getting log messages like the following. Why?
-
- Jun 21 12:00:00.000 client 10.0.0.1#1234: update denied
-
-A: Someone is trying to update your DNS data using the RFC2136 Dynamic Update
- protocol. Windows 2000 machines have a habit of sending dynamic update requests
- to DNS servers without being specifically configured to do so. If the update
- requests are coming from a Windows 2000 machine, see http://
- support.microsoft.com/support/kb/articles/q246/8/04.asp for information about
- how to turn them off.
+A: This may be a clock skew problem. Check that the the clocks on the
+ client and server are properly synchronised (e.g., using ntp).
Q: I see a log message like the following. Why?
couldn't open pid file '/var/run/named.pid': Permission denied
-A: You are most likely running named as a non-root user, and that user does not
- have permission to write in /var/run. The common ways of fixing this are to
- create a /var/run/named directory owned by the named user and set pid-file to "
- /var/run/named/named.pid", or set pid-file to "named.pid", which will put the
- file in the directory specified by the directory option (which, in this case,
- must be writable by the named user).
-
-Q: When I do a "dig . ns", many of the A records for the root servers are missing.
- Why?
-
-A: This is normal and harmless. It is a somewhat confusing side effect of the way
- BIND 9 does RFC2181 trust ranking and of the efforts BIND 9 makes to avoid
- promoting glue into answers.
-
- When BIND 9 first starts up and primes its cache, it receives the root server
- addresses as additional data in an authoritative response from a root server,
- and these records are eligible for inclusion as additional data in responses.
- Subsequently it receives a subset of the root server addresses as additional
- data in a non-authoritative (referral) response from a root server. This causes
- the addresses to now be considered non-authoritative (glue) data, which is not
- eligible for inclusion in responses.
-
- The server does have a complete set of root server addresses cached at all
- times, it just may not include all of them as additional data, depending on
- whether they were last received as answers or as glue. You can always look up
- the addresses with explicit queries like "dig a.root-servers.net A".
-
-Q: Zone transfers from my BIND 9 master to my Windows 2000 slave fail. Why?
-
-A: This may be caused by a bug in the Windows 2000 DNS server where DNS messages
- larger than 16K are not handled properly. This can be worked around by setting
- the option "transfer-format one-answer;". Also check whether your zone contains
- domain names with embedded spaces or other special characters, like "John\
- 032Doe\213s\032Computer", since such names have been known to cause Windows
- 2000 slaves to incorrectly reject the zone.
+A: You are most likely running named as a non-root user, and that user
+ does not have permission to write in /var/run. The common ways of
+ fixing this are to create a /var/run/named directory owned by the named
+ user and set pid-file to "/var/run/named/named.pid", or set pid-file to
+ "named.pid", which will put the file in the directory specified by the
+ directory option (which, in this case, must be writable by the named
+ user).
-Q: Why don't my zones reload when I do an "rndc reload" or SIGHUP?
-
-A: A zone can be updated either by editing zone files and reloading the server or
- by dynamic update, but not both. If you have enabled dynamic update for a zone
- using the "allow-update" option, you are not supposed to edit the zone file by
- hand, and the server will not attempt to reload it.
-
-Q: I can query the nameserver from the nameserver but not from other machines.
- Why?
+Q: I can query the nameserver from the nameserver but not from other
+ machines. Why?
-A: This is usually the result of the firewall configuration stopping the queries
- and / or the replies.
+A: This is usually the result of the firewall configuration stopping the
+ queries and / or the replies.
-Q: How can I make a server a slave for both an internal and an external view at
- the same time? When I tried, both views on the slave were transferred from the
- same view on the master.
+Q: How can I make a server a slave for both an internal and an external
+ view at the same time? When I tried, both views on the slave were
+ transferred from the same view on the master.
-A: You will need to give the master and slave multiple IP addresses and use those
- to make sure you reach the correct view on the other machine.
+A: You will need to give the master and slave multiple IP addresses and
+ use those to make sure you reach the correct view on the other machine.
Master: 10.0.1.1 (internal), 10.0.1.2 (external, IP alias)
internal:
@@ -246,8 +146,8 @@ A: You will need to give the master and slave multiple IP addresses and use thos
transfer-source 10.0.1.4;
query-source address 10.0.1.4;
- You put the external address on the alias so that all the other dns clients on
- these boxes see the internal view by default.
+ You put the external address on the alias so that all the other dns
+ clients on these boxes see the internal view by default.
A: BIND 9.3 and later: Use TSIG to select the appropriate view.
@@ -283,64 +183,38 @@ A: BIND 9.3 and later: Use TSIG to select the appropriate view.
...
};
-Q: I have FreeBSD 4.x and "rndc-confgen -a" just sits there.
-
-A: /dev/random is not configured. Use rndcontrol(8) to tell the kernel to use
- certain interrupts as a source of random events. You can make this permanent by
- setting rand_irqs in /etc/rc.conf.
-
- /etc/rc.conf
- rand_irqs="3 14 15"
-
- See also http://people.freebsd.org/~dougb/randomness.html
-
-Q: Why is named listening on UDP port other than 53?
-
-A: Named uses a system selected port to make queries of other nameservers. This
- behaviour can be overridden by using query-source to lock down the port and/or
- address. See also notify-source and transfer-source.
-
-Q: I get error messages like "multiple RRs of singleton type" and "CNAME and other
- data" when transferring a zone. What does this mean?
+Q: I get error messages like "multiple RRs of singleton type" and "CNAME
+ and other data" when transferring a zone. What does this mean?
-A: These indicate a malformed master zone. You can identify the exact records
- involved by transferring the zone using dig then running named-checkzone on it.
+A: These indicate a malformed master zone. You can identify the exact
+ records involved by transferring the zone using dig then running
+ named-checkzone on it.
dig axfr example.com @master-server > tmp
named-checkzone example.com tmp
- A CNAME record cannot exist with the same name as another record except for the
- DNSSEC records which prove its existance (NSEC).
-
- RFC 1034, Section 3.6.2: "If a CNAME RR is present at a node, no other data
- should be present; this ensures that the data for a canonical name and its
- aliases cannot be different. This rule also insures that a cached CNAME can be
- used without checking with an authoritative server for other RR types."
-
-Q: I get error messages like "named.conf:99: unexpected end of input" where 99 is
- the last line of named.conf.
+ A CNAME record cannot exist with the same name as another record except
+ for the DNSSEC records which prove its existence (NSEC).
-A: Some text editors (notepad and wordpad) fail to put a line title indication
- (e.g. CR/LF) on the last line of a text file. This can be fixed by "adding" a
- blank line to the end of the file. Named expects to see EOF immediately after
- EOL and treats text files where this is not met as truncated.
+ RFC 1034, Section 3.6.2: "If a CNAME RR is present at a node, no other
+ data should be present; this ensures that the data for a canonical name
+ and its aliases cannot be different. This rule also insures that a
+ cached CNAME can be used without checking with an authoritative server
+ for other RR types."
-Q: I get warning messages like "zone example.com/IN: refresh: failure trying
- master 1.2.3.4#53: timed out".
+Q: I get error messages like "named.conf:99: unexpected end of input"
+ where 99 is the last line of named.conf.
-A: Check that you can make UDP queries from the slave to the master
-
- dig +norec example.com soa @1.2.3.4
-
- You could be generating queries faster than the slave can cope with. Lower the
- serial query rate.
-
- serial-query-rate 5; // default 20
+A: Some text editors (notepad and wordpad) fail to put a line title
+ indication (e.g. CR/LF) on the last line of a text file. This can be
+ fixed by "adding" a blank line to the end of the file. Named expects to
+ see EOF immediately after EOL and treats text files where this is not
+ met as truncated.
Q: How do I share a dynamic zone between multiple views?
-A: You choose one view to be master and the second a slave and transfer the zone
- between views.
+A: You choose one view to be master and the second a slave and transfer
+ the zone between views.
Master 10.0.1.1:
key "external" {
@@ -354,7 +228,7 @@ A: You choose one view to be master and the second a slave and transfer the zone
};
view "internal" {
- match-clients { !external; 10.0.1/24; };
+ match-clients { !key external; 10.0.1/24; };
server 10.0.1.1 {
/* Deliver notify messages to external view. */
keys { external; };
@@ -368,7 +242,7 @@ A: You choose one view to be master and the second a slave and transfer the zone
};
view "external" {
- match-clients { external; any; };
+ match-clients { key external; any; };
zone "example.com" {
type slave;
file "external/example.db";
@@ -379,18 +253,19 @@ A: You choose one view to be master and the second a slave and transfer the zone
};
};
-Q: I get a error message like "zone wireless.ietf56.ietf.org/IN: loading master
- file primaries/wireless.ietf56.ietf.org: no owner".
+Q: I get a error message like "zone wireless.ietf56.ietf.org/IN: loading
+ master file primaries/wireless.ietf56.ietf.org: no owner".
-A: This error is produced when a line in the master file contains leading white
- space (tab/space) but the is no current record owner name to inherit the name
- from. Usually this is the result of putting white space before a comment.
- Forgeting the "@" for the SOA record or indenting the master file.
+A: This error is produced when a line in the master file contains leading
+ white space (tab/space) but the is no current record owner name to
+ inherit the name from. Usually this is the result of putting white
+ space before a comment, forgetting the "@" for the SOA record, or
+ indenting the master file.
Q: Why are my logs in GMT (UTC).
-A: You are running chrooted (-t) and have not supplied local timzone information
- in the chroot area.
+A: You are running chrooted (-t) and have not supplied local timezone
+ information in the chroot area.
FreeBSD: /etc/localtime
Solaris: /etc/TIMEZONE and /usr/share/lib/zoneinfo
@@ -398,71 +273,51 @@ A: You are running chrooted (-t) and have not supplied local timzone information
See also tzset(3) and zic(8).
-Q: I get the error message "named: capset failed: Operation not permitted" when
- starting named.
-
-A: The capability module, part of "Linux Security Modules/LSM", has not been
- loaded into the kernel. See insmod(8).
-
-Q: I get "rndc: connect failed: connection refused" when I try to run rndc.
+Q: I get "rndc: connect failed: connection refused" when I try to run
+ rndc.
A: This is usually a configuration error.
- First ensure that named is running and no errors are being reported at startup
- (/var/log/messages or equivalent). Running "named -g <usual arguments>" from a
- title can help at this point.
-
- Secondly ensure that named is configured to use rndc either by "rndc-confgen
- -a", rndc-confgen or manually. The Administrators Reference manual has details
- on how to do this.
+ First ensure that named is running and no errors are being reported at
+ startup (/var/log/messages or equivalent). Running "named -g <usual
+ arguments>" from a title can help at this point.
- Old versions of rndc-confgen used localhost rather than 127.0.0.1 in /etc/
- rndc.conf for the default server. Update /etc/rndc.conf if necessary so that
- the default server listed in /etc/rndc.conf matches the addresses used in
- named.conf. "localhost" has two address (127.0.0.1 and ::1).
+ Secondly ensure that named is configured to use rndc either by
+ "rndc-confgen -a", rndc-confgen or manually. The Administrators
+ Reference manual has details on how to do this.
- If you use "rndc-confgen -a" and named is running with -t or -u ensure that /
- etc/rndc.conf has the correct ownership and that a copy is in the chroot area.
- You can do this by re-running "rndc-confgen -a" with appropriate -t and -u
- arguments.
-
-Q: I don't get RRSIG's returned when I use "dig +dnssec".
+ Old versions of rndc-confgen used localhost rather than 127.0.0.1 in /
+ etc/rndc.conf for the default server. Update /etc/rndc.conf if
+ necessary so that the default server listed in /etc/rndc.conf matches
+ the addresses used in named.conf. "localhost" has two address
+ (127.0.0.1 and ::1).
-A: You need to ensure DNSSEC is enabled (dnssec-enable yes;).
-
-Q: I get "Error 1067" when starting named under Windows.
-
-A: This is the service manager saying that named exited. You need to examine the
- Application log in the EventViewer to find out why.
-
- Common causes are that you failed to create "named.conf" (usually "C:\windows\
- dns\etc\named.conf") or failed to specify the directory in named.conf.
-
- options {
- Directory "C:\windows\dns\etc";
- };
+ If you use "rndc-confgen -a" and named is running with -t or -u ensure
+ that /etc/rndc.conf has the correct ownership and that a copy is in the
+ chroot area. You can do this by re-running "rndc-confgen -a" with
+ appropriate -t and -u arguments.
Q: I get "transfer of 'example.net/IN' from 192.168.4.12#53: failed while
receiving responses: permission denied" error messages.
-A: These indicate a filesystem permission error preventing named creating /
- renaming the temporary file. These will usually also have other associated
- error messages like
+A: These indicate a filesystem permission error preventing named creating
+ / renaming the temporary file. These will usually also have other
+ associated error messages like
"dumping master file: sl/tmp-XXXX5il3sQ: open: permission denied"
- Named needs write permission on the directory containing the file. Named writes
- the new cache file to a temporary file then renames it to the name specified in
- named.conf to ensure that the contents are always complete. This is to prevent
- named loading a partial zone in the event of power failure or similar
- interrupting the write of the master file.
+ Named needs write permission on the directory containing the file.
+ Named writes the new cache file to a temporary file then renames it to
+ the name specified in named.conf to ensure that the contents are always
+ complete. This is to prevent named loading a partial zone in the event
+ of power failure or similar interrupting the write of the master file.
- Note file names are relative to the directory specified in options and any
- chroot directory ([<chroot dir>/][<options dir>]).
+ Note file names are relative to the directory specified in options and
+ any chroot directory ([<chroot dir>/][<options dir>]).
- If named is invoked as "named -t /chroot/DNS" with the following named.conf
- then "/chroot/DNS/var/named/sl" needs to be writable by the user named is
- running as.
+ If named is invoked as "named -t /chroot/DNS" with the following
+ named.conf then "/chroot/DNS/var/named/sl" needs to be writable by the
+ user named is running as.
options {
directory "/var/named";
@@ -474,35 +329,153 @@ A: These indicate a filesystem permission error preventing named creating /
masters { 192.168.4.12; };
};
-Q: How do I intergrate BIND 9 and Solaris SMF
+Q: I want to forward all DNS queries from my caching nameserver to another
+ server. But there are some domains which have to be served locally, via
+ rbldnsd.
-A: Sun has a blog entry describing how to do this.
+ How do I achieve this ?
- http://blogs.sun.com/roller/page/anay/Weblog?catname=%2FSolaris
+A: options {
+ forward only;
+ forwarders { <ip.of.primary.nameserver>; };
+ };
+
+ zone "sbl-xbl.spamhaus.org" {
+ type forward; forward only;
+ forwarders { <ip.of.rbldns.server> port 530; };
+ };
+
+ zone "list.dsbl.org" {
+ type forward; forward only;
+ forwarders { <ip.of.rbldns.server> port 530; };
+ };
+
+
+Q: Can you help me understand how BIND 9 uses memory to store DNS zones?
+
+ Some times it seems to take several times the amount of memory it needs
+ to store the zone.
+
+A: When reloading a zone named my have multiple copies of the zone in
+ memory at one time. The zone it is serving and the one it is loading.
+ If reloads are ultra fast it can have more still.
+
+ e.g. Ones that are transferring out, the one that it is serving and the
+ one that is loading.
+
+ BIND 8 destroyed the zone before loading and also killed off outgoing
+ transfers of the zone.
+
+ The new strategy allows slaves to get copies of the new zone regardless
+ of how often the master is loaded compared to the transfer time. The
+ slave might skip some intermediate versions but the transfers will
+ complete and it will keep reasonably in sync with the master.
+
+ The new strategy also allows the master to recover from syntax and
+ other errors in the master file as it still has an in-core copy of the
+ old contents.
+
+3. General Questions
+
+Q: I keep getting log messages like the following. Why?
+
+ Dec 4 23:47:59 client 10.0.0.1#1355: updating zone 'example.com/IN':
+ update failed: 'RRset exists (value dependent)' prerequisite not
+ satisfied (NXRRSET)
+
+A: DNS updates allow the update request to test to see if certain
+ conditions are met prior to proceeding with the update. The message
+ above is saying that conditions were not met and the update is not
+ proceeding. See doc/rfc/rfc2136.txt for more details on prerequisites.
+
+Q: I keep getting log messages like the following. Why?
+
+ Jun 21 12:00:00.000 client 10.0.0.1#1234: update denied
+
+A: Someone is trying to update your DNS data using the RFC2136 Dynamic
+ Update protocol. Windows 2000 machines have a habit of sending dynamic
+ update requests to DNS servers without being specifically configured to
+ do so. If the update requests are coming from a Windows 2000 machine,
+ see http://support.microsoft.com/support/kb/articles/q246/8/04.asp for
+ information about how to turn them off.
+
+Q: When I do a "dig . ns", many of the A records for the root servers are
+ missing. Why?
+
+A: This is normal and harmless. It is a somewhat confusing side effect of
+ the way BIND 9 does RFC2181 trust ranking and of the efforts BIND 9
+ makes to avoid promoting glue into answers.
+
+ When BIND 9 first starts up and primes its cache, it receives the root
+ server addresses as additional data in an authoritative response from a
+ root server, and these records are eligible for inclusion as additional
+ data in responses. Subsequently it receives a subset of the root server
+ addresses as additional data in a non-authoritative (referral) response
+ from a root server. This causes the addresses to now be considered
+ non-authoritative (glue) data, which is not eligible for inclusion in
+ responses.
+
+ The server does have a complete set of root server addresses cached at
+ all times, it just may not include all of them as additional data,
+ depending on whether they were last received as answers or as glue. You
+ can always look up the addresses with explicit queries like "dig
+ a.root-servers.net A".
+
+Q: Why don't my zones reload when I do an "rndc reload" or SIGHUP?
+
+A: A zone can be updated either by editing zone files and reloading the
+ server or by dynamic update, but not both. If you have enabled dynamic
+ update for a zone using the "allow-update" option, you are not supposed
+ to edit the zone file by hand, and the server will not attempt to
+ reload it.
+
+Q: Why is named listening on UDP port other than 53?
+
+A: Named uses a system selected port to make queries of other nameservers.
+ This behaviour can be overridden by using query-source to lock down the
+ port and/or address. See also notify-source and transfer-source.
+
+Q: I get warning messages like "zone example.com/IN: refresh: failure
+ trying master 1.2.3.4#53: timed out".
+
+A: Check that you can make UDP queries from the slave to the master
+
+ dig +norec example.com soa @1.2.3.4
+
+ You could be generating queries faster than the slave can cope with.
+ Lower the serial query rate.
+
+ serial-query-rate 5; // default 20
+
+Q: I don't get RRSIG's returned when I use "dig +dnssec".
+
+A: You need to ensure DNSSEC is enabled (dnssec-enable yes;).
Q: Can a NS record refer to a CNAME.
-A: No. The rules for glue (copies of the *address* records in the parent zones)
- and additional section processing do not allow it to work.
+A: No. The rules for glue (copies of the *address* records in the parent
+ zones) and additional section processing do not allow it to work.
- You would have to add both the CNAME and address records (A/AAAA) as glue to
- the parent zone and have CNAMEs be followed when doing additional section
- processing to make it work. No namesever implementation supports either of
- these requirements.
+ You would have to add both the CNAME and address records (A/AAAA) as
+ glue to the parent zone and have CNAMEs be followed when doing
+ additional section processing to make it work. No nameserver
+ implementation supports either of these requirements.
-Q: What does "RFC 1918 response from Internet for 0.0.0.10.IN-ADDR.ARPA" mean?
+Q: What does "RFC 1918 response from Internet for 0.0.0.10.IN-ADDR.ARPA"
+ mean?
-A: If the IN-ADDR.ARPA name covered refers to a internal address space you are
- using then you have failed to follow RFC 1918 usage rules and are leaking
- queries to the Internet. You should establish your own zones for these
- addresses to prevent you quering the Internet's name servers for these
- addresses. Please see http://as112.net/ for details of the problems you are
- causing and the counter measures that have had to be deployed.
+A: If the IN-ADDR.ARPA name covered refers to a internal address space you
+ are using then you have failed to follow RFC 1918 usage rules and are
+ leaking queries to the Internet. You should establish your own zones
+ for these addresses to prevent you querying the Internet's name servers
+ for these addresses. Please see http://as112.net/ for details of the
+ problems you are causing and the counter measures that have had to be
+ deployed.
- If you are not using these private addresses then a client has queried for
- them. You can just ignore the messages, get the offending client to stop
- sending you these messages as they are most probably leaking them or setup your
- own zones empty zones to serve answers to these queries.
+ If you are not using these private addresses then a client has queried
+ for them. You can just ignore the messages, get the offending client to
+ stop sending you these messages as they are most probably leaking them
+ or setup your own zones empty zones to serve answers to these queries.
zone "10.IN-ADDR.ARPA" {
type master;
@@ -535,42 +508,133 @@ A: If the IN-ADDR.ARPA name covered refers to a internal address space you are
Future versions of named are likely to do this automatically.
+Q: Will named be affected by the 2007 changes to daylight savings rules in
+ the US.
+
+A: No, so long as the machines internal clock (as reported by "date -u")
+ remains at UTC. The only visible change if you fail to upgrade your OS,
+ if you are in a affected area, will be that log messages will be a hour
+ out during the period where the old rules do not match the new rules.
+
+ For most OS's this change just means that you need to update the
+ conversion rules from UTC to local time. Normally this involves
+ updating a file in /etc (which sets the default timezone for the
+ machine) and possibly a directory which has all the conversion rules
+ for the world (e.g. /usr/share/zoneinfo). When updating the OS do not
+ forget to update any chroot areas as well. See your OS's documentation
+ for more details.
+
+ The local timezone conversion rules can also be done on a individual
+ basis by setting the TZ environment variable appropriately. See your
+ OS's documentation for more details.
+
+Q: Is there a bugzilla (or other tool) database that mere mortals can have
+ (read-only) access to for bind?
+
+A: No. The BIND 9 bug database is kept closed for a number of reasons.
+ These include, but are not limited to, that the database contains
+ proprietory information from people reporting bugs. The database has in
+ the past and may in future contain unfixed bugs which are capable of
+ bringing down most of the Internet's DNS infrastructure.
+
+ The release pages for each version contain up to date lists of bugs
+ that have been fixed post release. That is as close as we can get to
+ providing a bug database.
+
+4. Operating-System Specific Questions
+
+4.1. HPUX
+
+Q: I get the following error trying to configure BIND:
+
+ checking if unistd.h or sys/types.h defines fd_set... no
+ configure: error: need either working unistd.h or sys/select.h
+
+A: You have attempted to configure BIND with the bundled C compiler. This
+ compiler does not meet the minimum compiler requirements to for
+ building BIND. You need to install a ANSI C compiler and / or teach
+ configure how to find the ANSI C compiler. The later can be done by
+ adjusting the PATH environment variable and / or specifying the
+ compiler via CC.
+
+ ./configure CC=<compiler> ...
+
+4.2. Linux
+
+Q: Why do I get the following errors:
+
+ general: errno2result.c:109: unexpected error:
+ general: unable to convert errno to isc_result: 14: Bad address
+ client: UDP client handler shutting down due to fatal receive error: unexpected error
+
+A: This is the result of a Linux kernel bug.
+
+ See: http://marc.theaimsgroup.com/?l=linux-netdev&m=113081708031466&w=2
+
+Q: Why do I see 5 (or more) copies of named on Linux?
+
+A: Linux threads each show up as a process under ps. The approximate
+ number of threads running is n+4, where n is the number of CPUs. Note
+ that the amount of memory used is not cumulative; if each process is
+ using 10M of memory, only a total of 10M is used.
+
+ Newer versions of Linux's ps command hide the individual threads and
+ require -L to display them.
+
+Q: Why does BIND 9 log "permission denied" errors accessing its
+ configuration files or zones on my Linux system even though it is
+ running as root?
+
+A: On Linux, BIND 9 drops most of its root privileges on startup. This
+ including the privilege to open files owned by other users. Therefore,
+ if the server is running as root, the configuration files and zone
+ files should also be owned by root.
+
+Q: I get the error message "named: capset failed: Operation not permitted"
+ when starting named.
+
+A: The capability module, part of "Linux Security Modules/LSM", has not
+ been loaded into the kernel. See insmod(8).
+
Q: I'm running BIND on Red Hat Enterprise Linux or Fedora Core -
Why can't named update slave zone database files?
- Why can't named create DDNS journal files or update the master zones from
- journals?
+ Why can't named create DDNS journal files or update the master zones
+ from journals?
Why can't named create custom log files?
A: Red Hat Security Enhanced Linux (SELinux) policy security protections :
- Red Hat have adopted the National Security Agency's SELinux security policy (
- see http://www.nsa.gov/selinux ) and recommendations for BIND security , which
- are more secure than running named in a chroot and make use of the bind-chroot
- environment unecessary .
+ Red Hat have adopted the National Security Agency's SELinux security
+ policy ( see http://www.nsa.gov/selinux ) and recommendations for BIND
+ security , which are more secure than running named in a chroot and
+ make use of the bind-chroot environment unnecessary .
- By default, named is not allowed by the SELinux policy to write, create or
- delete any files EXCEPT in these directories:
+ By default, named is not allowed by the SELinux policy to write, create
+ or delete any files EXCEPT in these directories:
$ROOTDIR/var/named/slaves
$ROOTDIR/var/named/data
$ROOTDIR/var/tmp
- where $ROOTDIR may be set in /etc/sysconfig/named if bind-chroot is installed.
+ where $ROOTDIR may be set in /etc/sysconfig/named if bind-chroot is
+ installed.
- The SELinux policy particularly does NOT allow named to modify the $ROOTDIR/var
- /named directory, the default location for master zone database files.
+ The SELinux policy particularly does NOT allow named to modify the
+ $ROOTDIR/var/named directory, the default location for master zone
+ database files.
- SELinux policy overrules file access permissions - so even if all the files
- under /var/named have ownership named:named and mode rw-rw-r--, named will
- still not be able to write or create files except in the directories above,
- with SELinux in Enforcing mode.
+ SELinux policy overrules file access permissions - so even if all the
+ files under /var/named have ownership named:named and mode rw-rw-r--,
+ named will still not be able to write or create files except in the
+ directories above, with SELinux in Enforcing mode.
- So, to allow named to update slave or DDNS zone files, it is best to locate
- them in $ROOTDIR/var/named/slaves, with named.conf zone statements such as:
+ So, to allow named to update slave or DDNS zone files, it is best to
+ locate them in $ROOTDIR/var/named/slaves, with named.conf zone
+ statements such as:
zone "slave.zone." IN {
type slave;
@@ -584,8 +648,8 @@ A: Red Hat Security Enhanced Linux (SELinux) policy security protections :
};
- To allow named to create its cache dump and statistics files, for example, you
- could use named.conf options statements such as:
+ To allow named to create its cache dump and statistics files, for
+ example, you could use named.conf options statements such as:
options {
...
@@ -595,10 +659,11 @@ A: Red Hat Security Enhanced Linux (SELinux) policy security protections :
};
- You can also tell SELinux to allow named to update any zone database files, by
- setting the SELinux tunable boolean parameter 'named_write_master_zones=1',
- using the system-config-securitylevel GUI, using the 'setsebool' command, or in
- /etc/selinux/targeted/booleans.
+ You can also tell SELinux to allow named to update any zone database
+ files, by setting the SELinux tunable boolean parameter
+ 'named_write_master_zones=1', using the system-config-securitylevel
+ GUI, using the 'setsebool' command, or in /etc/selinux/targeted/
+ booleans.
You can disable SELinux protection for named entirely by setting the
'named_disable_trans=1' SELinux tunable boolean parameter.
@@ -610,66 +675,107 @@ A: Red Hat Security Enhanced Linux (SELinux) policy security protections :
named_cache_t: for files modifiable by named - $ROOTDIR/var/{tmp,named/{slaves,data}}
- If you want to retain use of the SELinux policy for named, and put named files
- in different locations, you can do so by changing the context of the custom
- file locations .
+ If you want to retain use of the SELinux policy for named, and put
+ named files in different locations, you can do so by changing the
+ context of the custom file locations .
- To create a custom configuration file location, eg. '/root/named.conf', to use
- with the 'named -c' option, do:
+ To create a custom configuration file location, e.g. '/root/
+ named.conf', to use with the 'named -c' option, do:
# chcon system_u:object_r:named_conf_t /root/named.conf
- To create a custom modifiable named data location, eg. '/var/log/named' for a
- log file, do:
+ To create a custom modifiable named data location, e.g. '/var/log/
+ named' for a log file, do:
# chcon system_u:object_r:named_cache_t /var/log/named
- To create a custom zone file location, eg. /root/zones/, do:
+ To create a custom zone file location, e.g. /root/zones/, do:
# chcon system_u:object_r:named_zone_t /root/zones/{.,*}
- See these man-pages for more information : selinux(8), named_selinux(8), chcon
- (1), setsebool(8)
+ See these man-pages for more information : selinux(8), named_selinux
+ (8), chcon(1), setsebool(8)
-Q: I want to forward all DNS queries from my caching nameserver to another server.
- But there are some domains which have to be served locally, via rbldnsd.
+4.3. Windows
- How do I achieve this ?
+Q: Zone transfers from my BIND 9 master to my Windows 2000 slave fail.
+ Why?
-A: options {
- forward only;
- forwarders { <ip.of.primary.nameserver>; };
- };
+A: This may be caused by a bug in the Windows 2000 DNS server where DNS
+ messages larger than 16K are not handled properly. This can be worked
+ around by setting the option "transfer-format one-answer;". Also check
+ whether your zone contains domain names with embedded spaces or other
+ special characters, like "John\032Doe\213s\032Computer", since such
+ names have been known to cause Windows 2000 slaves to incorrectly
+ reject the zone.
- zone "sbl-xbl.spamhaus.org" {
- type forward; forward only;
- forwarders { <ip.of.rbldns.server> port 530; };
+Q: I get "Error 1067" when starting named under Windows.
+
+A: This is the service manager saying that named exited. You need to
+ examine the Application log in the EventViewer to find out why.
+
+ Common causes are that you failed to create "named.conf" (usually "C:\
+ windows\dns\etc\named.conf") or failed to specify the directory in
+ named.conf.
+
+ options {
+ Directory "C:\windows\dns\etc";
};
- zone "list.dsbl.org" {
- type forward; forward only;
- forwarders { <ip.of.rbldns.server> port 530; };
+4.4. FreeBSD
+
+Q: I have FreeBSD 4.x and "rndc-confgen -a" just sits there.
+
+A: /dev/random is not configured. Use rndcontrol(8) to tell the kernel to
+ use certain interrupts as a source of random events. You can make this
+ permanent by setting rand_irqs in /etc/rc.conf.
+
+ /etc/rc.conf
+ rand_irqs="3 14 15"
+
+ See also http://people.freebsd.org/~dougb/randomness.html
+
+4.5. Solaris
+
+Q: How do I integrate BIND 9 and Solaris SMF
+
+A: Sun has a blog entry describing how to do this.
+
+ http://blogs.sun.com/roller/page/anay/Weblog?catname=%2FSolaris
+
+4.6. Apple Mac OS X
+
+Q: How do I run BIND 9 on Apple Mac OS X?
+
+A: If you run Tiger(Mac OS 10.4) or later then this is all you need to do:
+
+ % sudo rndc-confgen > /etc/rndc.conf
+
+ Copy the key statement from /etc/rndc.conf into /etc/rndc.key, e.g.:
+
+ key "rndc-key" {
+ algorithm hmac-md5;
+ secret "uvceheVuqf17ZwIcTydddw==";
};
+ Then start the relevant service:
-Q: Will named be affected by the 2007 changes to daylight savings rules in the US.
+ % sudo service org.isc.named start
-A: No, so long as the machines internal clock (as reported by "date -u") remains
- at UTC. The only visible change if you fail to upgrade your OS, if you are in a
- affected area, will be that log messages will be a hour out during the period
- where the old rules do not match the new rules.
+ This is persistent upon a reboot, so you will have to do it only once.
- For most OS's this change just means that you need to update the conversion
- rules from UTC to local time. Normally this involves updating a file in /etc
- (which sets the default timezone for the machine) and possibly a directory
- which has all the conversion rules for the world (e.g. /usr/share/zoneinfo).
- When updating the OS do not forget to update any chroot areas as well. See your
- OS's documetation for more details.
+A: Alternatively you can just generate /etc/rndc.key by running:
- The local timezone conversion rules can also be done on a individual basis by
- setting the TZ envirionment variable appropriately. See your OS's documentation
- for more details.
+ % sudo rndc-confgen -a
+
+ Then start the relevant service:
+
+ % sudo service org.isc.named start
+
+ Named will look for /etc/rndc.key when it starts if it doesn't have a
+ controls section or the existing controls are missing keys sub-clauses.
+ This is persistent upon a reboot, so you will have to do it only once.