ns_queryresolve

Overview

Query a name server

Syntax

ns_queryresolve type ?nameserver? domainname

Description

ns_queryresolve implements a subset of the nslookup program functions. You can query a nameserver about the specified domainname for records of any of the following types: a, cname, ns, soa, mx, or host. If there isn't a record for the particular type, the ns_set size will be 0 along with no fields.

The a type is for address lookups, and it will will return all of the addresses for a particular host. For the cname type, if the query comes back "null" from DNS, it returns a set with null fields. The ns, soa, and mx types require an authoritative domain/host or the command returns a set with no fields.

If no nameserver is specified, the first nameserver in the host's resolv.conf is used.

Example

    ##----- Example registered Tcl proc -----#
    ns_register_proc GET /nslookup ns_lookup
    proc ns_lookup {conn ignored} {
      set type {"a" "cname" "ns" "mx" "soa" "host" "host" }
      set domain {"aol.com" "www.aol.com" "aol.com" "aol.com"
    	"aol.com" "aol.com" "152.163.214.10" }
      set returnstring ""
      set nameserver ""
      for { set a 0 } {$a < [llength $type]} {incr a} {
            set nsset [ns_queryresolve [lindex $type $a] $nameserver
    			[lindex $domain $a] ]
            append returnstring "Type: [lindex $type $a]\n"
            set size [ns_set size $nsset]
            append returnstring "Ns_Set size : $size\n"
            for {set i 0} {$i < [ns_set size $nsset]} {incr i} {
                 set key [ns_set key $nsset $i]
                 set value [ns_set value $nsset $i]
                 append returnstring "$key : $value\n"
            }
            append returnstring "---------------------------------\n"
            ns_set free $nsset
      }
      ns_return $conn 200 text/plain $returnstring
    }

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