[arin-tech-discuss] Is ParentNetHandle mandatory in Net payload

Jon Worley jonw at arin.net
Thu Nov 13 17:12:39 EST 2014

Hello Sean,

There are several ways you might want to approach this.

Since the set of direct allocations issued to CenturyLink doesn’t change all that frequently - only when you get a new block from ARIN or via a transfer, or transfer an existing block to another organization - you might consider storing data on all of your direct allocations locally with relevant data - net handle, start IP, end IP, etc.  When you want to make a reassign call, you can reference that stored data to take the prefix/range to be reassigned and determine the associated parent net handle.  As an example, if you locally store data for the net handle NET-63-144-0-0-1 with a start IP address of and an end IP address of, you can then use that data to determine falls within NET-63-144-0-0-1.  The only caveat with this approach is that you’d need to update your local data whenever you add a new block, transfer a block to another organization, etc.

Another option would be to use ARIN’s Whois-RWS API to identify the parent net handle for a given IP address.  You can use that API to form a URL (http://whois.arin.net/rest/ip/ which asks for the network handle associated with  You’ll get back a payload with the network registration information, including the net handle.  Note that there’s no way to submit a call asking for only a direct allocation to be returned; if the IP address is already assigned to a customer, you’ll get that record back.  You’d have to then use the parent net handle from that record to submit a second query for registration information for that network, then verify what you get back is a direct allocation.  Keep in mind the Whois-RWS API is different than the Reg-RWS API.  It’s public so there’s no API key, the payloads might not be exactly the same, etc.

Those are the options that occur to me as being most useful.

If you have any further questions, comments, or concerns please respond to this message or contact me directly.


Jon Worley
Principal Technical Analyst
ARIN Registration Services
hostmaster at arin.net

From: <Zhao>, Sean <Sean.Zhao at CenturyLink.com<mailto:Sean.Zhao at CenturyLink.com>>
Date: Thursday, November 13, 2014 at 1:45 PM
To: "'arin-tech-discuss at arin.net<mailto:'arin-tech-discuss at arin.net>'" <arin-tech-discuss at arin.net<mailto:arin-tech-discuss at arin.net>>
Cc: "Talavagalu Matha Ajjaiah, Chandrasekhara" <Chandrasekhara.Talavagalumathaajjaiah at CenturyLink.com<mailto:Chandrasekhara.Talavagalumathaajjaiah at CenturyLink.com>>, "Grimes, Ronald" <Ron.Grimes at CenturyLink.com<mailto:Ron.Grimes at CenturyLink.com>>, "Sugandh, Nimesh" <Nimesh.Sugandh at CenturyLink.com<mailto:Nimesh.Sugandh at CenturyLink.com>>
Subject: [arin-tech-discuss] Is ParentNetHandle mandatory in Net payload


>From your payload on your website. parentNetHandle looks like it is mandatory. My question is how I know the parentNetHandle of an ip that I want to swip?

For example. I have an I went to http://whois.arin.net/rest/net/NET-63-145-104-192-1 or http://whois.ote.arin.net/rest/net/NET-63-145-104-192-1
I got now xml return. It used to return me net playload . But the net is parent net. If you changed, do you have alternative way to get parent net handle? All I need is a parent net handle of the ip I am going to assign.

<net xmlns="http://www.arin.net/regrws/core/v1" >
               <line number = "1">Line 1</line>
        <registrationDate>Tue Jan 25 16:17:18 EST 2011</registrationDate>


Sean Zhao
sean.zhao at centurylink.com<mailto:sean.zhao at centurylink.com>

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