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sample.edu - Institutional private tree
You can have you own private tree within you domain. It is usable for internal routing i.e. in case that you have several locations or so and you need to provide share different share translation different from golden tree or nrenum. You don't need any validation here.
There are also lots of managed private tree like enum.org enum.info and so on.
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| No Format |
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host -t naprt 1.1.1.6.5.4.3.2.1.e164.arpa.
or
dig -t naptr +short @nameserver 1.1.1.6.5.4.3.2.1.e164.arpa.
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These commands just retrive dns record from server. To test regexp you can use php scripts at nona.net where e164.arpa, e164.org, e164.info and enum.org are queried. At CESNET site you can find script that look looks up e164.apra and , nrenum.net and e164.org.