Lyndon Nerenberg wrote : -> Is there a tool available that will take an IP address and return the -> ASN attached to that network? I've been in situations before where this -> information would be useful, but not having access to the BGP routing -> information I'm not sure how to do this? (I've looked around some -> "likely" web sites - such as Merit - but haven't found anything.) -> -> The pressing need is for the ASN associated with 198.161.92.0. This -> network is connected to I*star, but I can't tell which of I*star's -> three ASNs it's homed on. (And they aren't being responsive to queries.)
Versions of traceroute that support the "A" option are also a nice quick way to get this info. Cisco routers do this by default. ex. sd-gw-1>traceroute cisco.com Translating "cisco.com"...domain server (207.67.247.4) [OK] Type escape sequence to abort. Tracing the route to cisco.com (198.92.30.31) 1 agis-atmnet.losangeles.agis.net (206.62.12.49) [AS 4200] 4 msec 4 msec 4 msec 2 a5-0.1009.santaclara3.agis.net (205.254.168.249) [AS 4200] 16 msec 12 msec 12 msec 3 mae-w.bbnplanet.net (198.32.136.14) 36 msec 32 msec 52 msec 4 paloalto-br2.bbnplanet.net (4.0.1.13) [AS 1] 32 msec 164 msec 240 msec 5 su-pr2.bbnplanet.net (131.119.0.218) [AS 200] 232 msec 36 msec 32 msec 6 cisco.bbnplanet.net (131.119.26.10) [AS 200] 36 msec 36 msec 36 msec 7 sj-wall-2.cisco.com (192.31.7.34) [AS 109] 36 msec 64 msec 36 msec 8 sj-eng-corp2.cisco.com (198.92.1.130) [AS 109] 40 msec 40 msec 44 msec 9 cisco.com (198.92.30.31) [AS 109] 36 msec 32 msec 33 msec sd-gw-1> Jim