1. Locating hosts by TULIP (Trilateration Utility for Locating IP hosts) Prepared by: Les Cottrell SLAC, Faran Javed NIIT, Shahryar Khan NIIT,Umar Kalim NIIT Internet2 fall members meeting San Diego, October 2007 http://www.slac.stanford.edu/grp/scs/net/talk07/i2mmfall07.ppt

2. Purpose Geo locate a host given its name or address Uses ping (RTT) measurements from landmarks – landmarks at known locations worldwide –RTT roughly proportional to distance in many cases Distance (km) = alpha * RTT (ms) –Velocity light in fibre ~ 0.6c or 1ms for 100km. –Use min RTT to reduce effect of queueing Using distance from RTT, triangulate to get lat/long

3. Goals Platform agnostic (Java & Perl (CGI)) Open, non-proprietary (cf. Traceware, Edgescape) Minimize security concerns Include developing regions Sustainable robust service Minimize manual effort (keep databases current) Provide an API to enable other applications We also wanted to verify the locations of the hosts in the PingER database.

4. Uses of Locating Hosts Choose content to send (e.g. language, local store) Security: pin-point suspicious hosts Where to get replicated service (e.g. Grid) Information for maps (e.g. visualroute) Efficiency of routing For Digital Divide & world-wide collaborations

5. How to get the location Database (e.g. DNS, whois, Geo IP tools) –Hard to keep up, may require subscription, maybe inaccurate, out- of-date or incomplete Traceroute and heuristics on names (Visual traceroute) RTTs (e.g. Octant from Cornell, Constraint based Geolocation from Belgium/Boston U) –Neither are active any more (student projects pointing the way?) They are complementary –Each has own strengths and weaknesses –Could/should be used together to validate each other and make corrections.

6. Simple Methodology (1) Client loads (Java Webstart), runs Java applet gets target from user Client requests Reflector to get pings to target Reflector requests Landmarks to ping target, Reflector Landmarks Client Target Ping target (web server running CGI script)

7. Simple Methodology (2) Client analyses data, Reflector send RTTs back to Client Landmarks send results back to Reflector Reflector Landmarks Client Target Ping target (web server running CGI script) visualizes and provides to user

8. Landmarks Want good geographical coverage for world. Need to be reliable, answer –No connection, timeouts, 100%loss (24 excellent PlanetLabs) –Respond quickly Not satellite connection Not a proxy PlanetLab ~ 150 landmarks Mainly in N. America and Europe SLAC/PingER reverse traceroute servers ~ 60, but more diverse, see www.slac.stanford.edu/comp/net/wan-mon/traceroute-srv.htm l

9. Security (lots of concerns) Can be used for DoS attacks against a target Looks like a potential scan of the target vs many hosts –Target ICMP replies to a large number of hosts CGI scripts (Perl) needs to be well vetted for holes Ability to discover & then blackhole abusers Only one TULIP client per host Landmarks and reflector both limit the number of running requests Centralized logging of all requests and results, plus analysis –Look for anomalies –Also discovers what landmarks are failing, who is requesting Possible privacy problems if locate a person’s host accurately (could add fuzz)

10. Problems Geostationary satellite connections –24Kmiles => RTT >370ms, heavily used in C. Asia and Africa IP name refers to multiple hosts (e.g. Google, Akamai, root name servers) in many locations Hosts move, have proxies etc. Indirect routing so RTT !~ distance –E. Asia vs. Australia seen from US Security concerns Duration for measurements (50 seconds to complete, results start arriving earlier) –Optimizing # of parallel requests from reflector, timeouts, tiering, remove poor landmarks Optimizing alpha in distance (km) = alpha * RTT (ms). Optimizing the choice of tier 0 landmarks, reliable & at edges, want very few, yet few false positives or mistakes –N. America: SLAC/CA, BNL/NY, AMPATH/FL, TRIUMF/CA(Vancouver), Winnipeg/CA, Houston, Saint Louis, Chicago –Europe: CERN/CH, ICTP/IT, DL/UK

11. Demo of early version www.slac.stanford.edu/comp/net/wan-mon/tulip –2 sets of landmarks: PlanetLabs & SLAC/PingER type –Enter host name or address & Locate Site –Raw results in Ping Results window –Visualize results in map

12. Evaluation of early version Use ~600 PingER hosts with “known” lat/long –Hosts in over 130 countries –Also validates PingER data 50% accurate to within 200 km, 70% within 1000km Ouch, not very successful, worse with RTT Need landmarks close to targets

13. Improvements Add more landmarks for better coverage: PlanetLab & more SLAC landmark deployment –(especially in developing world) Understand outliers, correct PingER dB Outliers: Multi-homed, e.g. yahoo, root servers, Move: e.g. supercomp Not at site of ASN: e.g. 134.79 SLAC host in Arizona Indirect routing: SFO-LA-SEA-VIC Alpha = 48.54 RTT/Dist (km/ms)

14. Look at Alpha Set alpha to right value to get correct distance from RTT and look at distributions Done for major US to N. America & major Europe to Europe sites

15. In progress Have stable version 1 –www.slac.stanford.edu/comp/net/wan-mon/tulip/www.slac.stanford.edu/comp/net/wan-mon/tulip/ Adding: –More landmark, filter out non-working instances –Integrate PlanetLabs & other landmark databases –Improved map visualization and zoom –Optimizing timing parameters (parallel streams, timeouts, landmark choices, alpha …) –Faster landmark response –GeoIP Tool estimates http://www.geoiptool.com/ –Tiering Redo evaluation, compare with other methods

16. Tiering Want to reduce the traffic hitting a target First find region target is in (tier 0 search) –Use few best landmarks in region Highly responsive, at edges of region –Determine most likely region (N. America, Europe, the rest) Then if client wants more detail use all landmarks in region to pin-point target Take 1/10 time for tier 0s vs all for N. America

17. More information/Questions Acknowledgements: –PlanetLab, SLAC reverse tracroute servers hosted in Africa, E. Asia, Latin America, Middle East, Russia, S. Asia TULIP Home Page: –http://www.slac.stanford.edu/comp/net/wan-mon/tulip/ PingER (driving reason for tool) –www-iepm.slac.stanford.edu/pinger,www-iepm.slac.stanford.edu/pinger TULIP 1 st Prize at All Asia Softec 2007 –http://www.niit.edu.pk/press/pages/releases/tulip.php