The ASN (Autonomous System Number) is a globally unique number assigned by a registrar for the purposes of Internet routing, To determine this issue the following command:
NOTE: The date and time part of the query is for the date / time you want to query.
whois -h whois.cymru.com " -v 5.42.134.35 2010-05-12 12:00:01 GMT"
returns:
AS | IP | BGP Prefix | CC | Registry | Allocated | Info | AS Name 8680 | 5.42.134.35 | 5.42.132.0/22 | GB | ripencc | 2012-05-16 | 2010-05-12 12:00:01 GMT | , GB
To query for some basic AS information directly:
whois -h whois.cymru.com " -v AS8680"
returns:
AS | CC | Registry | Allocated | AS Name 8680 | GB | ripencc | | , GB