We've written a Firefox Extension that displays the AS Number of every website visited along with some additional interesting information. All data is updated daily and the prefix to AS number mapping is from a DFZ BGP feed. You can download the extension here (a screenshot is available too): http://www.asnumber.networx.ch If you have any feedback, comments or feature requests please contact me either directly or at <asnumber at networx.ch>. We are working on providing a lot more information on the RIR IP address delegations but need fully access to all RIR's whois records for that. I've completed all paperwork last week and we should receive full access in the near future. Another thing I want to do is to show the number of RBL (Spamhaus, etc) listed IPs per AS. Contacting those RBLs is rather difficult and any help to discuss this directly with the RBL administrators is appreciated. Another request: So far we've got data servers in Europe and USA but none in Asia-Pacific. If you are able to host either a dedicated or shared (vmware/xen) FreeBSD server in Japan or South Korea with excellent inter-Asia connectivity please contact me directly. BGP Experts, Traffic & Network Engineering Gurus -- Andre Oppermann Internet Business Solutions AG Hardstrasse 235 8005 Zürich Switzerland Fon +41 44 277 75 75 Fax +41 44 277 75 77 Web www.networx.ch