![Page 1: The Effectiveness of Block Lists to Prevent Collisionsnamecollisions.net/downloads/wpnc14_slides_simpson...The Effectiveness of Block Lists to Prevent Collisions Matthew Thomas Yannis](https://reader034.vdocument.in/reader034/viewer/2022051508/5aa8b8d77f8b9a72188bf06e/html5/thumbnails/1.jpg)
The Effectiveness of Block Lists to Prevent CollisionsMatthew Thomas
Yannis Labrou
Andrew SimpsonMarch 2014
![Page 2: The Effectiveness of Block Lists to Prevent Collisionsnamecollisions.net/downloads/wpnc14_slides_simpson...The Effectiveness of Block Lists to Prevent Collisions Matthew Thomas Yannis](https://reader034.vdocument.in/reader034/viewer/2022051508/5aa8b8d77f8b9a72188bf06e/html5/thumbnails/2.jpg)
Verisign Public
About this talk
• Examine the efficacy of block listing based on sampled DNS traffic data in order to prevent potential name collision events.
� “Day in the life of the Internet” (DITL) Observations
� Longitudinal study of A+J Root NXDomain Traffic
2
![Page 3: The Effectiveness of Block Lists to Prevent Collisionsnamecollisions.net/downloads/wpnc14_slides_simpson...The Effectiveness of Block Lists to Prevent Collisions Matthew Thomas Yannis](https://reader034.vdocument.in/reader034/viewer/2022051508/5aa8b8d77f8b9a72188bf06e/html5/thumbnails/3.jpg)
Verisign Public
Data - Collection & Processing
3
![Page 4: The Effectiveness of Block Lists to Prevent Collisionsnamecollisions.net/downloads/wpnc14_slides_simpson...The Effectiveness of Block Lists to Prevent Collisions Matthew Thomas Yannis](https://reader034.vdocument.in/reader034/viewer/2022051508/5aa8b8d77f8b9a72188bf06e/html5/thumbnails/4.jpg)
Verisign Public
DITL Data
2013 Collisions Project DITL Analysis• JAS Global Advisors[1] and Demand Media[2] provided an
uncomplicated extraction of DITL data for the applied gTLDs by year and by TLD
• Traffic volume and measurements were described in numerous other publications.
• Details: https://www.dns-oarc.net/node/332
[1] Kevin White [2] Roy Hooper
4
![Page 5: The Effectiveness of Block Lists to Prevent Collisionsnamecollisions.net/downloads/wpnc14_slides_simpson...The Effectiveness of Block Lists to Prevent Collisions Matthew Thomas Yannis](https://reader034.vdocument.in/reader034/viewer/2022051508/5aa8b8d77f8b9a72188bf06e/html5/thumbnails/5.jpg)
Verisign Public
A and J Root NXDomain Data
• NXDomain traffic at Verisign-operated A+J root servers measured from July 16, 2013 until December 31, 2013.
• Contained ~3.6 billion NXD records and ~27.5 million unique second-level domains.*
5
![Page 6: The Effectiveness of Block Lists to Prevent Collisionsnamecollisions.net/downloads/wpnc14_slides_simpson...The Effectiveness of Block Lists to Prevent Collisions Matthew Thomas Yannis](https://reader034.vdocument.in/reader034/viewer/2022051508/5aa8b8d77f8b9a72188bf06e/html5/thumbnails/6.jpg)
Verisign Public
Data Processing
• Top Level Domain (TLD) Exclusions• Limited to applied for gTLDs
• “.home” and “.corp” removed due to high risk categorization[1]
• Second Level Domain (SLD) Exclusions• Chrome 10 character strings[2]
• Technique based on ICANN published methodologies[3]
[1] http://www.icann.org/en/news/announcements/announcement-3-05aug13-en.htm
[2] https://isc.sans.edu/diary/Google+Chrome+and+(weird)+DNS+requests/10312
[3] E.g. http://www.icann.org/en/about/agreements/registries/luxury/luxury-apd-report-12nov13-en.htm
6
![Page 7: The Effectiveness of Block Lists to Prevent Collisionsnamecollisions.net/downloads/wpnc14_slides_simpson...The Effectiveness of Block Lists to Prevent Collisions Matthew Thomas Yannis](https://reader034.vdocument.in/reader034/viewer/2022051508/5aa8b8d77f8b9a72188bf06e/html5/thumbnails/7.jpg)
Verisign Public
DITL Measurements
7
![Page 8: The Effectiveness of Block Lists to Prevent Collisionsnamecollisions.net/downloads/wpnc14_slides_simpson...The Effectiveness of Block Lists to Prevent Collisions Matthew Thomas Yannis](https://reader034.vdocument.in/reader034/viewer/2022051508/5aa8b8d77f8b9a72188bf06e/html5/thumbnails/8.jpg)
Verisign Public
DITL – Longitudinal SLD Growth
8
![Page 9: The Effectiveness of Block Lists to Prevent Collisionsnamecollisions.net/downloads/wpnc14_slides_simpson...The Effectiveness of Block Lists to Prevent Collisions Matthew Thomas Yannis](https://reader034.vdocument.in/reader034/viewer/2022051508/5aa8b8d77f8b9a72188bf06e/html5/thumbnails/9.jpg)
Verisign Public
DITL – Longitudinal SLD Growth
9
![Page 10: The Effectiveness of Block Lists to Prevent Collisionsnamecollisions.net/downloads/wpnc14_slides_simpson...The Effectiveness of Block Lists to Prevent Collisions Matthew Thomas Yannis](https://reader034.vdocument.in/reader034/viewer/2022051508/5aa8b8d77f8b9a72188bf06e/html5/thumbnails/10.jpg)
Verisign Public
DITL – Longitudinal SLD Growth
10
• Steady growth rate of new SLDs
• Increasing delta of Observed and Previously Observed
• Early indication of problems using potential block listing due to highly entropic system
Can we study a subset of
roots to measure the growth
rate and dynamics of SLDs?
![Page 11: The Effectiveness of Block Lists to Prevent Collisionsnamecollisions.net/downloads/wpnc14_slides_simpson...The Effectiveness of Block Lists to Prevent Collisions Matthew Thomas Yannis](https://reader034.vdocument.in/reader034/viewer/2022051508/5aa8b8d77f8b9a72188bf06e/html5/thumbnails/11.jpg)
Verisign Public
DITL – SLD Root Affinity
11
![Page 12: The Effectiveness of Block Lists to Prevent Collisionsnamecollisions.net/downloads/wpnc14_slides_simpson...The Effectiveness of Block Lists to Prevent Collisions Matthew Thomas Yannis](https://reader034.vdocument.in/reader034/viewer/2022051508/5aa8b8d77f8b9a72188bf06e/html5/thumbnails/12.jpg)
Verisign Public
DITL – SLD Root Affinity
12
![Page 13: The Effectiveness of Block Lists to Prevent Collisionsnamecollisions.net/downloads/wpnc14_slides_simpson...The Effectiveness of Block Lists to Prevent Collisions Matthew Thomas Yannis](https://reader034.vdocument.in/reader034/viewer/2022051508/5aa8b8d77f8b9a72188bf06e/html5/thumbnails/13.jpg)
Verisign Public
DITL – SLD Root Affinity
13
![Page 14: The Effectiveness of Block Lists to Prevent Collisionsnamecollisions.net/downloads/wpnc14_slides_simpson...The Effectiveness of Block Lists to Prevent Collisions Matthew Thomas Yannis](https://reader034.vdocument.in/reader034/viewer/2022051508/5aa8b8d77f8b9a72188bf06e/html5/thumbnails/14.jpg)
Verisign Public
DITL – SLD Root Affinity
14
![Page 15: The Effectiveness of Block Lists to Prevent Collisionsnamecollisions.net/downloads/wpnc14_slides_simpson...The Effectiveness of Block Lists to Prevent Collisions Matthew Thomas Yannis](https://reader034.vdocument.in/reader034/viewer/2022051508/5aa8b8d77f8b9a72188bf06e/html5/thumbnails/15.jpg)
Verisign Public
DITL – SLD Root Affinity
15
![Page 16: The Effectiveness of Block Lists to Prevent Collisionsnamecollisions.net/downloads/wpnc14_slides_simpson...The Effectiveness of Block Lists to Prevent Collisions Matthew Thomas Yannis](https://reader034.vdocument.in/reader034/viewer/2022051508/5aa8b8d77f8b9a72188bf06e/html5/thumbnails/16.jpg)
Verisign Public
DITL – SLD Root Affinity
16
![Page 17: The Effectiveness of Block Lists to Prevent Collisionsnamecollisions.net/downloads/wpnc14_slides_simpson...The Effectiveness of Block Lists to Prevent Collisions Matthew Thomas Yannis](https://reader034.vdocument.in/reader034/viewer/2022051508/5aa8b8d77f8b9a72188bf06e/html5/thumbnails/17.jpg)
Verisign Public
DITL – SLD Root Affinity
17
![Page 18: The Effectiveness of Block Lists to Prevent Collisionsnamecollisions.net/downloads/wpnc14_slides_simpson...The Effectiveness of Block Lists to Prevent Collisions Matthew Thomas Yannis](https://reader034.vdocument.in/reader034/viewer/2022051508/5aa8b8d77f8b9a72188bf06e/html5/thumbnails/18.jpg)
Verisign Public
DITL – SLD Root Affinity
18
![Page 19: The Effectiveness of Block Lists to Prevent Collisionsnamecollisions.net/downloads/wpnc14_slides_simpson...The Effectiveness of Block Lists to Prevent Collisions Matthew Thomas Yannis](https://reader034.vdocument.in/reader034/viewer/2022051508/5aa8b8d77f8b9a72188bf06e/html5/thumbnails/19.jpg)
Verisign Public
DITL – SLD Root Affinity
19
• Observational sampling at a specific subset of roots would be biased and of limited value for block listing purposes.
• High root affinity may prove useful to study a SLD’s longitudinal patterns by sampling from a specific root.
Do specific roots exhibit
higher levels of affinity that
may influence root sampling?
![Page 20: The Effectiveness of Block Lists to Prevent Collisionsnamecollisions.net/downloads/wpnc14_slides_simpson...The Effectiveness of Block Lists to Prevent Collisions Matthew Thomas Yannis](https://reader034.vdocument.in/reader034/viewer/2022051508/5aa8b8d77f8b9a72188bf06e/html5/thumbnails/20.jpg)
Verisign Public
DITL – Intra-Root Affinity
20
• Similarity function is a real-valued function that quantifies the similarity between two entities.
• Jaccard Index is a statistic for comparing the similarity and diversity of sample sets.
• Similarity matrix is a matrix of scores that represent the similarity between a number of data points.
![Page 21: The Effectiveness of Block Lists to Prevent Collisionsnamecollisions.net/downloads/wpnc14_slides_simpson...The Effectiveness of Block Lists to Prevent Collisions Matthew Thomas Yannis](https://reader034.vdocument.in/reader034/viewer/2022051508/5aa8b8d77f8b9a72188bf06e/html5/thumbnails/21.jpg)
Verisign Public
DITL – Intra-Root Affinity :: SLDs
21
![Page 22: The Effectiveness of Block Lists to Prevent Collisionsnamecollisions.net/downloads/wpnc14_slides_simpson...The Effectiveness of Block Lists to Prevent Collisions Matthew Thomas Yannis](https://reader034.vdocument.in/reader034/viewer/2022051508/5aa8b8d77f8b9a72188bf06e/html5/thumbnails/22.jpg)
Verisign Public
DITL – Intra-Root Affinity :: /24 Networks
22
![Page 23: The Effectiveness of Block Lists to Prevent Collisionsnamecollisions.net/downloads/wpnc14_slides_simpson...The Effectiveness of Block Lists to Prevent Collisions Matthew Thomas Yannis](https://reader034.vdocument.in/reader034/viewer/2022051508/5aa8b8d77f8b9a72188bf06e/html5/thumbnails/23.jpg)
Verisign Public
DITL – Intra-Root Affinity
23
• No inter-root affinity for either specific SLDs or recursive name server traffic.
How representative are
the A+J roots of the root
NXD traffic overall?
![Page 24: The Effectiveness of Block Lists to Prevent Collisionsnamecollisions.net/downloads/wpnc14_slides_simpson...The Effectiveness of Block Lists to Prevent Collisions Matthew Thomas Yannis](https://reader034.vdocument.in/reader034/viewer/2022051508/5aa8b8d77f8b9a72188bf06e/html5/thumbnails/24.jpg)
Verisign Public
Longitudinal Inspection Using A+J Roots
24
![Page 25: The Effectiveness of Block Lists to Prevent Collisionsnamecollisions.net/downloads/wpnc14_slides_simpson...The Effectiveness of Block Lists to Prevent Collisions Matthew Thomas Yannis](https://reader034.vdocument.in/reader034/viewer/2022051508/5aa8b8d77f8b9a72188bf06e/html5/thumbnails/25.jpg)
Verisign Public
Longitudinal Inspection Using A+J Roots
25
• On an annual basis, A+J combined observe just under 40% of all the SLDs observed across all roots
• Individually A and J each observe ~23% of all SLDs
• Corroborates intra-root affinity measures
What is the SLD growth
rate of Observed and
Previously Observed SLDs
over a longitudinal period?
![Page 26: The Effectiveness of Block Lists to Prevent Collisionsnamecollisions.net/downloads/wpnc14_slides_simpson...The Effectiveness of Block Lists to Prevent Collisions Matthew Thomas Yannis](https://reader034.vdocument.in/reader034/viewer/2022051508/5aa8b8d77f8b9a72188bf06e/html5/thumbnails/26.jpg)
Verisign Public
A+J Root Measurements
26
![Page 27: The Effectiveness of Block Lists to Prevent Collisionsnamecollisions.net/downloads/wpnc14_slides_simpson...The Effectiveness of Block Lists to Prevent Collisions Matthew Thomas Yannis](https://reader034.vdocument.in/reader034/viewer/2022051508/5aa8b8d77f8b9a72188bf06e/html5/thumbnails/27.jpg)
Verisign Public
Longitudinal Inspection Using A+J Roots
27
![Page 28: The Effectiveness of Block Lists to Prevent Collisionsnamecollisions.net/downloads/wpnc14_slides_simpson...The Effectiveness of Block Lists to Prevent Collisions Matthew Thomas Yannis](https://reader034.vdocument.in/reader034/viewer/2022051508/5aa8b8d77f8b9a72188bf06e/html5/thumbnails/28.jpg)
Verisign Public
Longitudinal Inspection Using A+J Roots
28
![Page 29: The Effectiveness of Block Lists to Prevent Collisionsnamecollisions.net/downloads/wpnc14_slides_simpson...The Effectiveness of Block Lists to Prevent Collisions Matthew Thomas Yannis](https://reader034.vdocument.in/reader034/viewer/2022051508/5aa8b8d77f8b9a72188bf06e/html5/thumbnails/29.jpg)
Verisign Public
Longitudinal Inspection Using A+J Roots
29
• Average percentage of new SLDs on a given day is 22.5%
• Same trend seen in year over year DITL measurements.
• Highly entropic SLD universe: any small collection window will only account for a small percentage of SLDs over the subsequent period of time.
• Pattern is so consistent that any collection period will always have a large number of never seen before SLDs.
How frequently do SLDs occur?
![Page 30: The Effectiveness of Block Lists to Prevent Collisionsnamecollisions.net/downloads/wpnc14_slides_simpson...The Effectiveness of Block Lists to Prevent Collisions Matthew Thomas Yannis](https://reader034.vdocument.in/reader034/viewer/2022051508/5aa8b8d77f8b9a72188bf06e/html5/thumbnails/30.jpg)
Verisign Public
A+J SLD Daily Occurrence Frequencies
30
![Page 31: The Effectiveness of Block Lists to Prevent Collisionsnamecollisions.net/downloads/wpnc14_slides_simpson...The Effectiveness of Block Lists to Prevent Collisions Matthew Thomas Yannis](https://reader034.vdocument.in/reader034/viewer/2022051508/5aa8b8d77f8b9a72188bf06e/html5/thumbnails/31.jpg)
Verisign Public
A+J SLD Daily Occurrence Frequencies
31
• Nearly 80% of the observed SLDs appear on only one day
• Only 5% of SLD’s (~ 1.375 million) appeared on more than 20 days
What temporal patterns
do non-singleton SLDs
exhibit?
![Page 32: The Effectiveness of Block Lists to Prevent Collisionsnamecollisions.net/downloads/wpnc14_slides_simpson...The Effectiveness of Block Lists to Prevent Collisions Matthew Thomas Yannis](https://reader034.vdocument.in/reader034/viewer/2022051508/5aa8b8d77f8b9a72188bf06e/html5/thumbnails/32.jpg)
Verisign Public
A+J SLD Periodicity
32
![Page 33: The Effectiveness of Block Lists to Prevent Collisionsnamecollisions.net/downloads/wpnc14_slides_simpson...The Effectiveness of Block Lists to Prevent Collisions Matthew Thomas Yannis](https://reader034.vdocument.in/reader034/viewer/2022051508/5aa8b8d77f8b9a72188bf06e/html5/thumbnails/33.jpg)
Verisign Public
A+J SLD Periodicity
33
![Page 34: The Effectiveness of Block Lists to Prevent Collisionsnamecollisions.net/downloads/wpnc14_slides_simpson...The Effectiveness of Block Lists to Prevent Collisions Matthew Thomas Yannis](https://reader034.vdocument.in/reader034/viewer/2022051508/5aa8b8d77f8b9a72188bf06e/html5/thumbnails/34.jpg)
Verisign Public
A+J SLD Periodicity
34
![Page 35: The Effectiveness of Block Lists to Prevent Collisionsnamecollisions.net/downloads/wpnc14_slides_simpson...The Effectiveness of Block Lists to Prevent Collisions Matthew Thomas Yannis](https://reader034.vdocument.in/reader034/viewer/2022051508/5aa8b8d77f8b9a72188bf06e/html5/thumbnails/35.jpg)
Verisign Public
A+J SLD Periodicity
35
![Page 36: The Effectiveness of Block Lists to Prevent Collisionsnamecollisions.net/downloads/wpnc14_slides_simpson...The Effectiveness of Block Lists to Prevent Collisions Matthew Thomas Yannis](https://reader034.vdocument.in/reader034/viewer/2022051508/5aa8b8d77f8b9a72188bf06e/html5/thumbnails/36.jpg)
Verisign Public
A+J SLD Periodicity
36
• Given a sequence of NXD requests for a given SLD:
• Alternatively, we may look for the maximum value in the distribution to better size our collection window.
![Page 37: The Effectiveness of Block Lists to Prevent Collisionsnamecollisions.net/downloads/wpnc14_slides_simpson...The Effectiveness of Block Lists to Prevent Collisions Matthew Thomas Yannis](https://reader034.vdocument.in/reader034/viewer/2022051508/5aa8b8d77f8b9a72188bf06e/html5/thumbnails/37.jpg)
Verisign Public
A+J SLD Periodicity
37
![Page 38: The Effectiveness of Block Lists to Prevent Collisionsnamecollisions.net/downloads/wpnc14_slides_simpson...The Effectiveness of Block Lists to Prevent Collisions Matthew Thomas Yannis](https://reader034.vdocument.in/reader034/viewer/2022051508/5aa8b8d77f8b9a72188bf06e/html5/thumbnails/38.jpg)
Verisign Public
A+J SLD Periodicity
38
• Many SLDs exhibit some form of “burstiness”.
• 37% of domains exhibit average inter-query period of 1 week or longer.
Do larger collection
windows increase the
efficacy of block listing?
![Page 39: The Effectiveness of Block Lists to Prevent Collisionsnamecollisions.net/downloads/wpnc14_slides_simpson...The Effectiveness of Block Lists to Prevent Collisions Matthew Thomas Yannis](https://reader034.vdocument.in/reader034/viewer/2022051508/5aa8b8d77f8b9a72188bf06e/html5/thumbnails/39.jpg)
Verisign Public
Effectiveness of Larger Block Listing Windows
39
![Page 40: The Effectiveness of Block Lists to Prevent Collisionsnamecollisions.net/downloads/wpnc14_slides_simpson...The Effectiveness of Block Lists to Prevent Collisions Matthew Thomas Yannis](https://reader034.vdocument.in/reader034/viewer/2022051508/5aa8b8d77f8b9a72188bf06e/html5/thumbnails/40.jpg)
Verisign Public
Effectiveness of Larger Block Listing Windows
40
![Page 41: The Effectiveness of Block Lists to Prevent Collisionsnamecollisions.net/downloads/wpnc14_slides_simpson...The Effectiveness of Block Lists to Prevent Collisions Matthew Thomas Yannis](https://reader034.vdocument.in/reader034/viewer/2022051508/5aa8b8d77f8b9a72188bf06e/html5/thumbnails/41.jpg)
Verisign Public
Effectiveness of Larger Block Listing Windows
41
![Page 42: The Effectiveness of Block Lists to Prevent Collisionsnamecollisions.net/downloads/wpnc14_slides_simpson...The Effectiveness of Block Lists to Prevent Collisions Matthew Thomas Yannis](https://reader034.vdocument.in/reader034/viewer/2022051508/5aa8b8d77f8b9a72188bf06e/html5/thumbnails/42.jpg)
Verisign Public
Effectiveness of Larger Block Listing Windows
42
![Page 43: The Effectiveness of Block Lists to Prevent Collisionsnamecollisions.net/downloads/wpnc14_slides_simpson...The Effectiveness of Block Lists to Prevent Collisions Matthew Thomas Yannis](https://reader034.vdocument.in/reader034/viewer/2022051508/5aa8b8d77f8b9a72188bf06e/html5/thumbnails/43.jpg)
Verisign Public
Effectiveness of Larger Block Listing Windows
43
![Page 44: The Effectiveness of Block Lists to Prevent Collisionsnamecollisions.net/downloads/wpnc14_slides_simpson...The Effectiveness of Block Lists to Prevent Collisions Matthew Thomas Yannis](https://reader034.vdocument.in/reader034/viewer/2022051508/5aa8b8d77f8b9a72188bf06e/html5/thumbnails/44.jpg)
Verisign Public
Effectiveness of Larger Block Listing Windows
44
![Page 45: The Effectiveness of Block Lists to Prevent Collisionsnamecollisions.net/downloads/wpnc14_slides_simpson...The Effectiveness of Block Lists to Prevent Collisions Matthew Thomas Yannis](https://reader034.vdocument.in/reader034/viewer/2022051508/5aa8b8d77f8b9a72188bf06e/html5/thumbnails/45.jpg)
Verisign Public
Effectiveness of Larger Block Listing Windows
45
![Page 46: The Effectiveness of Block Lists to Prevent Collisionsnamecollisions.net/downloads/wpnc14_slides_simpson...The Effectiveness of Block Lists to Prevent Collisions Matthew Thomas Yannis](https://reader034.vdocument.in/reader034/viewer/2022051508/5aa8b8d77f8b9a72188bf06e/html5/thumbnails/46.jpg)
Verisign Public
Effectiveness of Larger Block Listing Windows
46
![Page 47: The Effectiveness of Block Lists to Prevent Collisionsnamecollisions.net/downloads/wpnc14_slides_simpson...The Effectiveness of Block Lists to Prevent Collisions Matthew Thomas Yannis](https://reader034.vdocument.in/reader034/viewer/2022051508/5aa8b8d77f8b9a72188bf06e/html5/thumbnails/47.jpg)
Verisign Public
Effectiveness of Larger Block Listing Windows
47
![Page 48: The Effectiveness of Block Lists to Prevent Collisionsnamecollisions.net/downloads/wpnc14_slides_simpson...The Effectiveness of Block Lists to Prevent Collisions Matthew Thomas Yannis](https://reader034.vdocument.in/reader034/viewer/2022051508/5aa8b8d77f8b9a72188bf06e/html5/thumbnails/48.jpg)
Verisign Public
Effectiveness of Larger Block Listing Windows
48
![Page 49: The Effectiveness of Block Lists to Prevent Collisionsnamecollisions.net/downloads/wpnc14_slides_simpson...The Effectiveness of Block Lists to Prevent Collisions Matthew Thomas Yannis](https://reader034.vdocument.in/reader034/viewer/2022051508/5aa8b8d77f8b9a72188bf06e/html5/thumbnails/49.jpg)
Verisign Public
Effectiveness of Larger Block Listing Windows
49
![Page 50: The Effectiveness of Block Lists to Prevent Collisionsnamecollisions.net/downloads/wpnc14_slides_simpson...The Effectiveness of Block Lists to Prevent Collisions Matthew Thomas Yannis](https://reader034.vdocument.in/reader034/viewer/2022051508/5aa8b8d77f8b9a72188bf06e/html5/thumbnails/50.jpg)
Verisign Public
Effectiveness of Larger Block Listing Windows
50
![Page 51: The Effectiveness of Block Lists to Prevent Collisionsnamecollisions.net/downloads/wpnc14_slides_simpson...The Effectiveness of Block Lists to Prevent Collisions Matthew Thomas Yannis](https://reader034.vdocument.in/reader034/viewer/2022051508/5aa8b8d77f8b9a72188bf06e/html5/thumbnails/51.jpg)
Verisign Public
Effectiveness of Larger Block Listing Windows
51
![Page 52: The Effectiveness of Block Lists to Prevent Collisionsnamecollisions.net/downloads/wpnc14_slides_simpson...The Effectiveness of Block Lists to Prevent Collisions Matthew Thomas Yannis](https://reader034.vdocument.in/reader034/viewer/2022051508/5aa8b8d77f8b9a72188bf06e/html5/thumbnails/52.jpg)
Verisign Public
Effectiveness of Larger Block Listing Windows
52
• With larger window sizes, the percentage of blocked SLDs increases but the effect of that increase asymptotically approaches an upper bound.
• For an given window size, the ratio diminishes with time –not unexpected due to highly entropic SLD universe.
![Page 53: The Effectiveness of Block Lists to Prevent Collisionsnamecollisions.net/downloads/wpnc14_slides_simpson...The Effectiveness of Block Lists to Prevent Collisions Matthew Thomas Yannis](https://reader034.vdocument.in/reader034/viewer/2022051508/5aa8b8d77f8b9a72188bf06e/html5/thumbnails/53.jpg)
Verisign Public
Concluding Remarks
• Block Listing SLDs to prevent name collisions based on sampled DNS data appears to be an ineffective approach.
• Highly dynamic and evolving SLD universe.
• Strong SLD-root affinity will require all root data sets.
• Temporal patterns exhibited by SLDs require longer observational windows, yet provide diminishing returns as time continues.
• Alternative methodologies should be explored in conjunction or in place of DNS sampled data block listing.
53
![Page 54: The Effectiveness of Block Lists to Prevent Collisionsnamecollisions.net/downloads/wpnc14_slides_simpson...The Effectiveness of Block Lists to Prevent Collisions Matthew Thomas Yannis](https://reader034.vdocument.in/reader034/viewer/2022051508/5aa8b8d77f8b9a72188bf06e/html5/thumbnails/54.jpg)
© 2014 VeriSign, Inc. All rights reserved. VERISIGN and other trademarks, service marks, and designs ar e registered or unregistered trademarks of VeriSign, Inc. and its subsidiaries in the United S tates and in foreign countries. All other trademark s are property of their respective owners.