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Diffstat (limited to 'usr.sbin/bind/FAQ')
| -rw-r--r-- | usr.sbin/bind/FAQ | 822 |
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. |