Re: Finding ASN from IP address

[Jeff Wasilko <jeffw () smoe org>]

On Thu, Oct 09, 2003 at 09:49:32AM -0700, Avleen Vig wrote:
> I want to create a mapping of IP addresses to ASN, for a specific like
> of IP addresses. Eg:
>   1.2.3.4
>   12.34.56.78
>
> etc, gathered from my system logs.
>
> What is the best way of doing this?

Team Cymru is offering a IP to ASN Whois service:

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Fellow networkers,
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Team Cymru is happy to announce the availability of a public whois
server dedicated to mapping IP numbers to ASNs, located at
whois.cymru.com.? You can find the link to this tool at:
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http://www.cymru.com/BGP/whois.html
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This link has been added to our main BGP data page available at:
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http://www.cymru.com/BGP/index.html
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We have also extended the functionality of this daemon to support BULK
IP submissions for those who wish to further optimize their queries with
netcat.
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Following is a quick overview of how to use it:
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$ whois -h whois.cymru.com <IP>
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Where <IP> is replaced by the IP you'd like to map, like so:
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$ whois -h whois.cymru.com 4.2.2.1
??? ASN |?????????????? IP | Name
?? 3356 |????????? 4.2.2.1 | LEVEL3 Level 3 Communications
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You can also include port information, and/or timestamps in your
queries.? Be sure to include quotes around your queries, or the daemon
will interpret your request as multiple lines:
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$ whois -h whois.cymru.com "4.2.2.1 -0600 GMT"
??? ASN |?????????????? IP |??????????? Info | Name
?? 3356 |????????? 4.2.2.1 |?????? -0600 GMT | LEVEL3 Level 3
Communications
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For instructions on how to submit BULK queries via netcat, simply issue
the following command:
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$ whois -h whois.cymru.com help
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We hope you find this tool useful.? Stay tuned for more features!? 
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If you have any comments or suggestions as to how we might improve this
service, feel free to let us know!
?
Thanks,
Steve, for Team Cymru 
http://www.cymru.com
--
Stephen Gill