Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

SD Supercomputer Center researchers find unnecessary traffic saturating a key Internet ’root’ server

24.01.2003


Scientists at the San Diego Supercomputer Center (SDSC) at UCSD analyzing traffic to one of the 13 Domain Name System (DNS) “root” servers at the heart of the Internet found that the server spends the majority of its time dealing with unnecessary queries. DNS root servers provide a critical link between users and the Internet’s routing infrastructure by mapping text host names to numeric Internet Protocol (IP) addresses. Researchers at the Cooperative Association for Internet Data Analysis (CAIDA) at SDSC conducted a detailed analysis of 152 million messages received on Oct. 4, 2002, by a root server in California, and discovered that 98 percent of the queries it received during 24 hours were unnecessary. The researchers believe that the other 12 DNS root servers likely receive similarly large amounts of bad requests.


Locations of the Internet’s 13 Domain Name System “root” servers.
Credit: SDSC/CAIDA



Some experts regard the system of 13 DNS root servers, the focus of several studies by CAIDA researchers, as a potential weak link in the global Internet. Spikes in DNS query traffic caused by distributed denial-of-service attacks are routinely handled by root server operators. Occasionally, as on Oct. 21, 2002, all 13 root servers are attacked simultaneously. Although no serious damage resulted from that incident, Richard A. Clarke, chairman of the President’s Critical Infrastructure Protection Board and special advisor to the president for cybersecurity, has expressed concern that attacks against root servers could potentially disrupt the entire Internet. CAIDA researchers will discuss their analysis of the root server and other cybersecurity findings with Clarke during his visit to SDSC on Jan. 28. CAIDA researchers will also present a paper detailing some of their DNS analysis at the 2003 Passive and Active Measurement Workshop April 6–8 at UCSD.

Only about 2 percent of the 152 million queries received by the root server in California on Oct. 4 were legitimate, while 98 percent were classified as unnecessary. CAIDA researchers are seeking to understand why any root server would receive such an enormous number of broken queries daily from lower level servers. “If the system were functioning properly, it seems that a single source should need to send no more than 1,000 or so queries to a root name server in a 24-hour period,” said CAIDA researcher Duane Wessels. “Yet we see millions of broken queries from certain sources.”


Wessels categorized all the queries received by the California root server on Oct. 4, 2002, into nine types. About 70 percent of all the queries were either identical, or repeat requests for addresses within the same domain. It is as if a telephone user were dialing directory assistance to get the phone numbers of certain businesses, and repeating the directory-assistance calls again and again. Lower level servers and Internet service providers (ISPs) could save—or cache—these responses from root servers, improving overall Domain Name Service performance.

About 12 percent of the queries received by the root server on Oct. 4, were for nonexistent top-level domains, such as “.elvis”, “.corp”, and “.localhost”. Registered top-level domains include country codes such as “.au” for Australia, “.jp” for Japan, or “.us” for the United States, as well as generic domains such as “.com”, “.net”, and “.edu”. In addition, 7 percent of all the queries already contained an IP address instead of a host name, which made the job of mapping it to an IP address irrelevant.

Researchers believe that many bad requests occur because organizations have misconfigured packet filters and firewalls, security mechanisms intended to restrict certain types of network traffic. When packet filters and firewalls allow outgoing DNS queries, but block the resulting incoming responses, software on the inside of the firewall can make the same DNS queries over and over, waiting for responses that can’t get through. Name server operators can use new tools such as dnstop, a software program written by Wessels and available at http://www.caida.org/tools/utilities/dnstop/ to detect and warn of these and other misconfigurations, significantly reducing bad requests.

Name-service errors in software implementations were reported as early as 1992, but some of these bugs are still with us today. Explosive Internet growth during the last decade exacerbates problems caused by defective name servers.

Rex Graham | EurekAlert!
Further information:
http://www.caida.org/projects/dns-analysis/
http://www.caida.org/tools/utilities/dnstop/
http://ucsdnews.ucsd.edu/newsrel/science/sdscRoot.htm

More articles from Information Technology:

nachricht Open source software helps researchers extract key insights from huge sensor datasets
22.03.2019 | Universität des Saarlandes

nachricht Touchscreens go 3D with buttons that pulsate and vibrate under your fingertips
14.03.2019 | Universität des Saarlandes

All articles from Information Technology >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: The taming of the light screw

DESY and MPSD scientists create high-order harmonics from solids with controlled polarization states, taking advantage of both crystal symmetry and attosecond electronic dynamics. The newly demonstrated technique might find intriguing applications in petahertz electronics and for spectroscopic studies of novel quantum materials.

The nonlinear process of high-order harmonic generation (HHG) in gases is one of the cornerstones of attosecond science (an attosecond is a billionth of a...

Im Focus: Magnetic micro-boats

Nano- and microtechnology are promising candidates not only for medical applications such as drug delivery but also for the creation of little robots or flexible integrated sensors. Scientists from the Max Planck Institute for Polymer Research (MPI-P) have created magnetic microparticles, with a newly developed method, that could pave the way for building micro-motors or guiding drugs in the human body to a target, like a tumor. The preparation of such structures as well as their remote-control can be regulated using magnetic fields and therefore can find application in an array of domains.

The magnetic properties of a material control how this material responds to the presence of a magnetic field. Iron oxide is the main component of rust but also...

Im Focus: Self-healing coating made of corn starch makes small scratches disappear through heat

Due to the special arrangement of its molecules, a new coating made of corn starch is able to repair small scratches by itself through heat: The cross-linking via ring-shaped molecules makes the material mobile, so that it compensates for the scratches and these disappear again.

Superficial micro-scratches on the car body or on other high-gloss surfaces are harmless, but annoying. Especially in the luxury segment such surfaces are...

Im Focus: Stellar cartography

The Potsdam Echelle Polarimetric and Spectroscopic Instrument (PEPSI) at the Large Binocular Telescope (LBT) in Arizona released its first image of the surface magnetic field of another star. In a paper in the European journal Astronomy & Astrophysics, the PEPSI team presents a Zeeman- Doppler-Image of the surface of the magnetically active star II Pegasi.

A special technique allows astronomers to resolve the surfaces of faraway stars. Those are otherwise only seen as point sources, even in the largest telescopes...

Im Focus: Heading towards a tsunami of light

Researchers at Chalmers University of Technology and the University of Gothenburg, Sweden, have proposed a way to create a completely new source of radiation. Ultra-intense light pulses consist of the motion of a single wave and can be described as a tsunami of light. The strong wave can be used to study interactions between matter and light in a unique way. Their research is now published in the scientific journal Physical Review Letters.

"This source of radiation lets us look at reality through a new angle - it is like twisting a mirror and discovering something completely different," says...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

International Modelica Conference with 330 visitors from 21 countries at OTH Regensburg

11.03.2019 | Event News

Selection Completed: 580 Young Scientists from 88 Countries at the Lindau Nobel Laureate Meeting

01.03.2019 | Event News

LightMAT 2019 – 3rd International Conference on Light Materials – Science and Technology

28.02.2019 | Event News

 
Latest News

Solving the efficiency of Gram-negative bacteria

22.03.2019 | Life Sciences

Bacteria bide their time when antibiotics attack

22.03.2019 | Life Sciences

Open source software helps researchers extract key insights from huge sensor datasets

22.03.2019 | Information Technology

VideoLinks
Science & Research
Overview of more VideoLinks >>>