(Tcl) MX Lookup Mail Server Domain by Email Address

How to find the mail server for a given email address. Returns the domain name of the primary mail server.

Note: This example requires Chilkat v11.0.0 or greater.

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load ./chilkat.dll

set success 0

# This example requires the Chilkat API to have been previously unlocked.
# See Global Unlock Sample for sample code.

set dns [new_CkDns]

set json [new_CkJsonObject]

set emailAddr "bob@example.com"

# This gets all MX domains for an email address.  (Typically one domain.)
# The preferred domain will be at index 0 (see below).
set success [CkDns_Query $dns "MX" $emailAddr $json]
if {$success == 0} then {
    puts [CkDns_lastErrorText $dns]
    delete_CkDns $dns
    delete_CkJsonObject $json
    exit
}

set i 0
set count_i [CkJsonObject_SizeOfArray $json "answer.mx"]
while {$i < $count_i} {
    CkJsonObject_put_I $json $i
    set domain [CkJsonObject_stringOf $json "answer.mx[i].domain"]
    puts "$domain"
    set i [expr $i + 1]
}

delete_CkDns $dns
delete_CkJsonObject $json