NDB(8)                                                     NDB(8)

          query, ipquery, mkhash, mkdb, mkhosts, cs, csquery, dns,
          dnstcp, dnsquery, dnsdebug, dnsgetip, inform - network

          ndb/query [ -am ] [ -f dbfile ] attr value [ rattr ]
          ndb/ipquery attr value rattr...
          ndb/mkhash file attr
          ndb/mkhosts [ domain [ dbfile ] ]
          ndb/cs [ -46n ] [ -f dbfile ] [ -x netmtpt ]
          ndb/csquery [ -s ] [ /net/cs [ addr... ] ]
          ndb/dns [ -norRs ] [ -a maxage ] [ -f dbfile ] [ -N target ]
          [ -x netmtpt ] [ -z program ]
          ndb/dnstcp [ -arR ] [ -f dbfile ] [ -x netmtpt ] [ conn-dir
          ndb/dnsquery [ -x ] [ /net/dns ]
          ndb/dnsdebug [ -rx ] [ -f dbfile ] [ [ @server ] domain-name
          [ type ] ]
          ndb/dnsgetip [ -ax ] domain-name
          ndb/inform [ -x netmtpt ]

          The network database holds administrative information used
          by network programs such as dhcpd(8), ipconfig(8), con(1),

          Ndb/query searches the database dbfile (/lib/ndb/local by
          default) for an attribute of type attr and value value. If
          rattr is not specified, all entries matched by the search
          are printed.  If rattr is specified, the value of the first
          pair with attribute rattr of all the matched entries nor-
          mally is printed.  Under -m and rattr, the values of all
          pairs with a rattr attribute within the first matching entry
          are printed.  Under -a and rattr, all values of pairs with a
          rattr attribute within all entries are printed.

          Ndb/ipquery uses ndbipinfo (see ndb(2)) to search for the
          values of the attributes rattr corresponding to the system
          with entries of attribute type attr and value value.

          Ndb/inform sends an RFC2136 DNS inform packet to a name-
          server to associate the host's IP address with its DNS name.
          This is required if the domain's nameserver is a Microsoft
          Windows Active Directory controller.  The host's domain name
          will be sent to the AD controller unless a tuple of the form
          inform=xxx is found in the host's ndb entry.

        Database maintenance

     Page 1                       Plan 9             (printed 4/13/24)

     NDB(8)                                                     NDB(8)

          Ndb/mkhash creates a hash file for all entries with
          attribute attr in database file file. The hash files are
          used by ndb/query and by the ndb library routines.

          Ndb/mkdb is used in concert with awk(1) scripts to convert
          uucp systems files and IP host files into database files.
          It is very specific to the situation at Murray Hill.

          When the database files change underfoot, ndb/cs and ndb/dns
          track them properly.  Nonetheless, to keep the database
          searches efficient it is necessary to run ndb/mkhash when-
          ever the files are modified.  It may be profitable to con-
          trol this by a frequent cron(8) job.

          Ndb/mkhosts generates a BSD style hosts, hosts.txt, and
          hosts.equiv files from an ndb data base file specified on
          the command line (default /lib/ndb/local).  For local rea-
          sons the files are called hosts.1127, astro.txt, and

        Connection service
          Ndb/cs is a server used by dial(2) to translate network
          names.  It is started at boot time.  It finds out what net-
          works are configured by looking for /net/*/clone when it
          starts.  It can also be told about networks by writing to
          /net/cs a message of the form:

               add net1 net2 ...

          Ndb/cs also sets the system name in /dev/sysname if it can
          figure it out.  The options are:

          -4  Only look up IPv4 addresses (A records) when consulting
              DNS.  The default is to also look up v6 addresses (AAAA
              records).  Writing `ipv4' to /net/cs will toggle IP v4
          -6  Only look up IPv6 addresses in DNS.  Writing `ipv6' to
              /net/cs toggles v6 lookups.
          -f  supplies the name of the data base file to use, default
          -n  causes cs to do nothing but set the system name.
          -x  specifies the mount point of the network.

          Ndb/csquery queries ndb/cs to see how it resolves addresses.
          Ndb/csquery prompts for addresses and prints what ndb/cs
          returns.  Server defaults to /net/cs.  If any addrs are
          specified, ndb/csquery prints their translations and immedi-
          ately exits.  The exit status will be nil only if all
          addresses were successfully translated.  The -s flag sets
          exit status without printing any results.

     Page 2                       Plan 9             (printed 4/13/24)

     NDB(8)                                                     NDB(8)

        Domain name service
          Ndb/dns serves ndb/cs and remote systems by translating
          Internet domain names.  Ndb/dns is started at boot time.  By
          default dns serves only requests written to /net/dns.  Pro-
          grams must seek to offset 0 before reading or writing
          /net/dns or /net/cs.  The options are:

          -a  sets the maximum time in seconds that an unreferenced
              domain name will remain cached.  The default is one hour
          -f  supplies the name of the data base file to use, default
          -n  whenever a DNS zone that we serve changes, send UDP
              NOTIFY messages to any dns slaves for that zone (see the
              `dnsslave' attribute below).
          -N  sets the goal for the number of domain names cached to
              target rather than the default of 8,000.
          -o  used with -s, -o causes dns to assume that it straddles
              inside and outside networks and that the outside network
              is mounted on /net.alt.  Queries for inside addresses
              will be sent via /net/udp (or /net/tcp in response to
              truncated replies) and those for outside addresses via
              /net.alt/udp (or /net.alt/tcp).  This makes dns suitable
              for serving non-Plan-9 systems in an organization with
              firewalls, DNS proxies, etc., particularly if they don't
              work very well.  See `Straddling Server' below for
          -r  act as a resolver only: send `recursive' queries, asking
              the other servers to complete lookups.  If present,
              /env/DNSSERVER must be a space-separated list of such
              DNS servers' IP addresses, otherwise optional ndb(6) dns
              attributes name DNS servers to forward queries to.
          -R  ignore the `recursive' bit on incoming requests.  Do not
              complete lookups on behalf of remote systems.
          -s  also answer domain requests sent to UDP port 53.
          -x  specifies the mount point of the network.
          -z  whenever we receive a UDP NOTIFY message, run program
              with the domain name of the area as its argument.

          When the -r option is specified, the servers used come from
          the dns attribute in the database.  For example, to specify
          a set of dns servers that will resolve requests for systems
          on the network mh-net:

               ipnet=mh-net ip= ipmask=
               dom=ns1.cs.bell-labs.com ip=
               dom=ns2.cs.bell-labs.com ip=

          The server for a domain is indicated by a database entry
          containing both a dom and a ns attribute.

     Page 3                       Plan 9             (printed 4/13/24)

     NDB(8)                                                     NDB(8)

               dom=A.ROOT-SERVERS.NET ip=
               dom=B.ROOT-SERVERS.NET ip=
               dom=C.ROOT-SERVERS.NET ip=

          The last three lines provide a mapping for the server names
          to their ip addresses.  This is only a hint and will be
          superseded from whatever is learned from servers owning the

        Authoritative Name Servers
          You can also serve a subtree of the domain name space from
          the local database.  You indicate subtrees that you would
          like to serve by adding an soa= attribute to the root entry.
          For example, the Bell Labs CS research domain is:

               dom=cs.bell-labs.com soa=
                    refresh=3600 ttl=3600
                    mx=mail.research.bell-labs.com pref=20
                    mx=plan9.bell-labs.com pref=10

          Here, the mb entry is the mail address of the person respon-
          sible for the domain (default postmaster).  The mx entries
          list mail exchangers for the domain name and refresh and ttl
          define the area refresh interval and the minimum TTL for
          records in this domain.  The dnsslave entries specify slave
          DNS servers that should be notified when the domain changes.
          The notification also requires the -n flag.

        Reverse Domains
          You can also serve reverse lookups (returning the name that
          goes with an IP address) by adding an soa= attribute to the
          entry defining the root of the reverse space.

          For example, to provide reverse lookup for all addresses in
          starting with `135.104' or `fd00::', ndb must contain a
          record like:

               dom=104.135.in-addr.arpa soa=
                    dom=d.f.ip6.arpa soa=    # special case, rfc 4193
                    refresh=3600 ttl=3600

     Page 4                       Plan 9             (printed 4/13/24)

     NDB(8)                                                     NDB(8)


          Notice the form of the reverse address.  For IPv4, it's the
          bytes of the address range you are serving reversed and
          expressed in decimal, and with `.in-addr.arpa' appended.
          For IPv6, it's the nibbles (4-bit fields) of the address
          range you are serving reversed and expressed in hexadecimal,
          and with `.ip6.arpa' appended.  These are the standard forms
          for a domain name in a PTR record.

          If such an soa entry exists in the database, reverse
          addresses will automatically be generated from any IP
          addresses in the database that are under this root.  For

               dom=ns1.cs.bell-labs.com ip=

          will automatically create both forward and reverse entries
          for ns1.cs.bell-labs.com.  Unlike other DNS servers, there's
          no way to generate inconsistent forward and reverse entries.

        Classless reverse delegation
          Following RFC 2317, it is possible to serve reverse DNS data
          for IPv4 subnets smaller than /24.  Declare the non-/24 sub-
          net, the reverse domain and the individual systems.

          For example, this is how to serve RFC-2317 ptr records for
          the subnet `'.

               ipnet=our-t1 ip= ipmask=/123
               dom= soa=
                    refresh=3600 ttl=3600
               ip= dom=router.our-domain.com

        Delegating Name Service Authority
          Delegation of a further subtree to another set of name
          servers is indicated by an soa=delegated attribute.


          Nameservers within the delegated domain (as in this example)
          must have their IP addresses listed elsewhere in ndb files.

        Wildcards, MX and CNAME records
          Wild-carded domain names can also be used.  For example, to
          specify a mail forwarder for all Bell Labs research systems:

     Page 5                       Plan 9             (printed 4/13/24)

     NDB(8)                                                     NDB(8)


          `Cname' aliases may be established by adding a cname
          attribute giving the real domain name; the name attached to
          the dom attribute is the alias.  `Cname' aliases are
          severely restricted; the aliases may have no other
          attributes than dom and are daily further restricted in
          their use by new RFCs.

               cname=anna.cs.bell-labs.com dom=www.cs.bell-labs.com

          makes www....  a synonym for the canonical name anna.....

        Straddling Server
          Many companies have an inside network protected from outside
          access with firewalls.  They usually provide internal `root'
          DNS servers (of varying reliability and correctness) that
          serve internal domains and pass on DNS queries for outside
          domains to the outside, relaying the results back and cach-
          ing them for future use.  Some companies don't even let DNS
          queries nor replies through their firewalls at all, in
          either direction.

          In such a situation, running dns -so on a machine that
          imports access to the outside network via /net.alt from a
          machine that straddles the firewalls, or that straddles the
          firewalls itself, will let internal machines query such a
          machine and receive answers from outside nameservers for
          outside addresses and inside nameservers for inside
          addresses, giving the appearance of a unified domain name
          space, while bypassing the corporate DNS proxies or fire-
          walls.  This is different from running dns -s and dns -sRx
          /net.alt -f /lib/ndb/external on the same machine, which
          keeps the inside and outside namespaces entirely separate.

          Under -o, several sys names are significant: inside-dom,
          inside-ns, and outside-ns.  Inside-dom should contain a
          series of dom pairs naming domains internal to the organiza-
          tion.  Inside-ns should contain a series of ip pairs naming
          the internal DNS `root' servers.  Outside-ns should contain
          a series of ip pairs naming the external DNS servers to con-

        Zone Transfers and TCP
          Dnstcp is invoked, usually from /rc/bin/service/tcp53, to
          answer DNS queries with long answers via TCP, notably to
          transfer a zone within the database dbfile (default
          /lib/ndb/local) to its invoker on the network at netmtpt
          (default /net).  Standard input will be read for DNS
          requests and the DNS answers will appear on standard output.
          Recursion is disabled by -R; acting as a pure resolver is

     Page 6                       Plan 9             (printed 4/13/24)

     NDB(8)                                                     NDB(8)

          enabled by -r.  Unless the -a flag is provided, clients
          requesting DNS zone transfer must be listed with a dnsslave
          attribute for the relevant domain.  If conn-dir is provided,
          it is assumed to be a directory within netmtpt/tcp and is
          used to find the caller's address.

        DNS Queries and Debugging
          Ndb/dnsquery can be used to query ndb/dns to see how it
          resolves requests.  Ndb/dnsquery prompts for commands of the

               domain-name request-type

          where request-type can be ip, ipv6, mx, ns, cname, ptr....
          In the case of the inverse query type, ptr, dnsquery will
          reverse the ip address and tack on the .in-addr.arpa if nec-
          essary.  The -x option switches ndb/dnsquery to query the
          dns server on /net.alt instead of /net

          Ndb/dnsdebug is like ndb/dnsquery but bypasses the local
          server.  It communicates via UDP (and sometimes TCP) with
          the domain name servers in the same way that the local
          resolver would and displays all packets received.  The query
          can be specified on the command line or can be prompted for.
          The queries look like those of ndb/dnsquery with one addi-
          tion.  Ndb/dnsdebug can be directed to query a particular
          name server by the command @name-server.  From that point
          on, all queries go to that name server rather than being
          resolved by dnsdebug. The @ command returns query resolution
          to dnsdebug. Finally, any command preceded by a @name-server
          sets the name server only for that command.

          Normally dnsdebug uses the /net interface and the database
          file /lib/ndb/local.  The -f option supplies the name of the
          data base file to use.  The -r option is the same as for
          ndb/dns. The -x option directs dnsdebug to use the /net.alt
          interface and /lib/ndb/external database file.

          Ndb/dnsgetip resolves and prints A and AAAA records without
          consulting ndb/dns . By default, ndb/dnsgetip queries A
          records first and then AAAA records. As with ndb/dns,
          /env/DNSSERVER or ndb(6) dns attributes are used as the DNS
          server. The -a flag will return all records. The -x option
          switches ndb/dnsgetip to query the dns server through
          /net.alt instead of /net.

          Look up helix in ndb.

               % ndb/query sys helix
               sys=helix dom=helix.research.bell-labs.com bootf=/mips/9powerboot
                    ip= ether=080069020427

     Page 7                       Plan 9             (printed 4/13/24)

     NDB(8)                                                     NDB(8)

          Look up plan9.bell-labs.com and its IP address in the DNS.

               % ndb/dnsquery
               > plan9.bell-labs.com ip
               plan9.bell-labs.com ip
               > ptr
      ptr plan9.bell-labs.com
      ptr ampl.com

          Print the names of all systems that boot via PXE.

               % ndb/query -a bootf /386/9bootpxe sys

          /env/DNSSERVER       resolver's DNS servers' IP addresses.
          /lib/ndb/local       first database file searched
          /lib/ndb/local.*     hash files for /lib/ndb/local
          /srv/cs              service file for ndb/cs
          /net/cs              where /srv/cs gets mounted
          /srv/dns             service file for ndb/dns
          /net/dns             where /srv/dns gets mounted


          ndb(2), ndb(6)

          Ndb databases are case-sensitive; ethernet addresses must be
          in lower-case hexadecimal.

     Page 8                       Plan 9             (printed 4/13/24)