Linux Certif

Toute la documentation sur la certification Linux LPI

unbound-control

NAME

unbound-control - Unbound remote server control utility.

SYNOPSIS

unbound-control [-h] [-c cfgfile] [-s server] command

DESCRIPTION

Unbound-control performs remote administration on the unbound(8) DNS server. It reads the configuration file, contacts the unbound server over SSL sends the command and displays the result.

The available options are:

-h

Show the version and commandline option help.

-c cfgfile

The config file to read with settings. If not given the default config file /etc/unbound/unbound.conf is used.

-s server[@port]

IPv4 or IPv6 address of the server to contact. If not given, the address is read from the config file.

COMMANDS

There are several commands that the server understands.

start

Start the server. Simply execs unbound(8). The unbound executable is searched for in the PATH set in the environment. It is started with the config file specified using -c or the default config file.

stop

Stop the server. The server daemon exits.

reload

Reload the server. This flushes the cache and reads the config file fresh.

verbosity number

Change verbosity value for logging. Same values as verbosity keyword in unbound.conf(5). This new setting lasts until the server is issued a reload (taken from config file again), or the next verbosity control command.

stats

Print statistics. Resets the internal counters to zero, this can be controlled using the statistics-cumulative config statement. Statistics are printed with one [name]: [value] per line.

status

Display server status. Exit code 3 if not running (the connection to the port is refused), 1 on error, 0 if running.

local_zone name type

Add new local zone with name and type. Like local-zone config statement. If the zone already exists, the type is changed to the given argument.

local_zone_remove name

Remove the local zone with the given name. Removes all local data inside it. If the zone does not exist, the command succeeds.

local_data RR data...

Add new local data, the given resource record. Like local-data config statement, except for when no covering zone exists. In that case this remote control command creates a transparent zone with the same name as this record. This command is not good at returning detailed syntax errors.

local_data_remove name

Remove all RR data from local name. If the name already has no items, nothing happens. Often results in NXDOMAIN for the name (in a static zone), but if the name has become an empty nonterminal (there is still data in domain names below the removed name), NOERROR nodata answers are the result for that name.

dump_cache

The contents of the cache is printed in a text format to stdout. You can redirect it to a file to store the cache in a file.

load_cache

The contents of the cache is loaded from stdin. Uses the same format as dump_cache uses. Loading the cache with old, or wrong data can result in old or wrong data returned to clients.

lookup name

Print to stdout the name servers that would be used to look up the name specified.

flush name

Remove the name from the cache. Removes the types A, AAAA, NS, SOA, CNAME, DNAME, MX, PTR, SRV and NAPTR. Because that is fast to do. Other record types can be removed using flush_type or flush_zone.

flush_type name type

Remove the name, type information from the cache.

flush_zone name

Remove all information at or below the name from the cache. The rrsets and key entries are removed so that new lookups will be performed. This needs to walk and inspect the entire cache, and is a slow operation.

EXIT CODE

The unbound-control program exits with status code 1 on error, 0 on success.

SET UP

The setup requires a self-signed certificate and private keys for both the server and client. The script unbound-control-setup generates these in the default run directory, or with -d in another directory. Run the script under the same username as you have configured in unbound.conf so that the daemon is permitted to read the files, for example with:

     sudo -u unbound unbound-control-setup
 

If you have not configured a username in unbound.conf, the keys need read permission for the user credentials under which the daemon is started. The script preserves private keys present in the directory. After running the script as root, turn on control-enable in unbound.conf.

STATISTIC COUNTERS

The stats command shows a number of statistic counters.

threadX.num.queries

number of queries received by thread

threadX.num.cachehits

number of queries that were successfully answered using a cache lookup

threadX.num.cachemiss

number of queries that needed recursive processing

threadX.num.recursivereplies

The number of replies sent to queries that needed recursive processing. Could be smaller than threadX.num.cachemiss if due to timeouts no replies were sent for some queries.

threadX.requestlist.avg

The average number of requests in the internal recursive processing request list on insert of a new incoming recursive processing query.

threadX.requestlist.max

Maximum size attained by the internal recursive processing request list.

threadX.requestlist.overwritten

Number of requests in the request list that were overwritten by newer entries. This happens if there is a flood of queries that recursive processing and the server has a hard time.

threadX.requestlist.exceeded

Queries that were dropped because the request list was full. This happens if a flood of queries need recursive processing, and the server can not keep up.

threadX.requestlist.current.all

Current size of the request list, includes internally generated queries (such as priming queries and glue lookups).

threadX.requestlist.current.user

Current size of the request list, only the requests from client queries.

threadX.recursion.time.avg

Average time it took to answer queries that needed recursive processing. Note that queries that were answered from the cache are not in this average.

threadX.recursion.time.median

The median of the time it took to answer queries that needed recursive processing. The median means that 50% of the user queries were answered in less than this time. Because of big outliers (usually queries to non responsive servers), the average can be bigger than the median. This median has been calculated by interpolation from a histogram.

total.num.queries

summed over threads.

total.num.cachehits

summed over threads.

total.num.cachemiss

summed over threads.

total.num.recursivereplies

summed over threads.

total.requestlist.avg

averaged over threads.

total.requestlist.max

the maximum of the thread requestlist.max values.

total.requestlist.overwritten

summed over threads.

total.requestlist.exceeded

summed over threads.

total.requestlist.current.all

summed over threads.

total.recursion.time.median

averaged over threads.

time.now

current time in seconds since 1970.

time.up

uptime since server boot in seconds.

time.elapsed

time since last statistics printout, in seconds.

EXTENDED STATISTICS

mem.total.sbrk

If sbrk(2) is available, an estimate of the heap size of the program in number of bytes. Close to the total memory used by the program, as reported by top and ps. Could be wrong if the OS allocates memory non-contiguously.

mem.cache.rrset

Memory in bytes in use by the RRset cache.

mem.cache.message

Memory in bytes in use by the message cache.

mem.mod.iterator

Memory in bytes in use by the iterator module.

mem.mod.validator

Memory in bytes in use by the validator module. Includes the key cache and negative cache.

histogram.<sec>.<usec>.to.<sec>.<usec>

Shows a histogram, summed over all threads. Every element counts the recursive queries whose reply time fit between the lower and upper bound. Times larger or equal to the lowerbound, and smaller than the upper bound. There are 40 buckets, with bucket sizes doubling.

num.query.type.A

The total number of queries over all threads with query type A. Printed for the other query types as well, but only for the types for which queries were received, thus =0 entries are omitted for brevity.

num.query.type.other

Number of queries with query types 256-65535.

num.query.class.IN

The total number of queries over all threads with query class IN (internet). Also printed for other classes (such as CH (CHAOS) sometimes used for debugging), or NONE, ANY, used by dynamic update. num.query.class.other is printed for classes 256-65535.

num.query.opcode.QUERY

The total number of queries over all threads with query opcode QUERY. Also printed for other opcodes, UPDATE, ...

num.query.tcp

Number of queries that were made using TCP towards the unbound server.

num.query.ipv6

Number of queries that were made using IPv6 towards the unbound server.

num.query.flags.RD

The number of queries that had the RD flag set in the header. Also printed for flags QR, AA, TC, RA, Z, AD, CD. Note that queries with flags QR, AA or TC may have been rejected because of that.

num.query.edns.present

number of queries that had an EDNS OPT record present.

num.query.edns.DO

number of queries that had an EDNS OPT record with the DO (DNSSEC OK) bit set. These queries are also included in the num.query.edns.present number.

num.answer.rcode.NXDOMAIN

The number of answers to queries, from cache or from recursion, that had the return code NXDOMAIN. Also printed for the other return codes.

num.answer.rcode.nodata

The number of answers to queries that had the pseudo return code nodata. This means the actual return code was NOERROR, but additionally, no data was carried in the answer (making what is called a NOERROR/NODATA answer). These queries are also included in the num.answer.rcode.NOERROR number. Common for AAAA lookups when an A record exists, and no AAAA.

num.answer.secure

Number of answers that were secure. The answer validated correctly. The AD bit might have been set in some of these answers, where the client signalled (with DO or AD bit in the query) that they were ready to accept the AD bit in the answer.

num.answer.bogus

Number of answers that were bogus. These answers resulted in SERVFAIL to the client because the answer failed validation.

num.rrset.bogus

The number of rrsets marked bogus by the validator. Increased for every RRset inspection that fails.

unwanted.queries

Number of queries that were refused or dropped because they failed the access control settings.

unwanted.replies

Replies that were unwanted or unsolicited. Could have been random traffic, delayed duplicates, very late answers, or could be spoofing attempts. Some low level of late answers and delayed duplicates are to be expected with the UDP protocol. Very high values could indicate a threat (spoofing).

FILES

/etc/unbound/unbound.conf

unbound configuration file.

/etc/unbound

directory with private keys (unbound_server.key and unbound_control.key) and self-signed certificates (unbound_server.pem and unbound_control.pem).

SEE ALSO

unbound.conf(5), unbound(8).