The Attack and Defense of Computers
Dr. 許 富 皓
Who is Managing
the Internet today?
Who is Managing the Internet today?
Core functions of the Internet are managed by a
nonprofit organization named the Internet Corporation
for Assigned Names and Numbers (ICANN;
Created in Oct. 1998, ICANN is assuming responsibility for a
set of technical functions previously performed under U.S.
government contract by the Internet Assigned Numbers
Authority (IANA; http://www.iana.org ) and other groups.
• P.S.: In practice, IANA still handles much of the day-to-day operations,
but these will eventually be transitioned to ICANN
Some of ICANN’s Major Functions
ICANN coordinates the assignment of the following
identifiers that must be globally unique for the Internet
Internet domain names.
IP address numbers.
Protocol parameters and port numbers.
ICANN also coordinates the stable operation of the
Internet’s root DNS server system.
Three Special ICANN Suborganizations
Address Supporting Organization (ASO;
Generic Names Supporting Organization (GNSO;
Country Code Domain Name Supporting Organization
(CCNSO; http://www.ccnso.icann.org )
Reviews and develops recommendations on IP address policy and advises
the ICANN Board on these matters.
Allocates IP address blocks to various Regional Internet Registries (RIRs).
A RIR’s responsibility is to manage, distribute, and register public Internet
number resources within their respective regions.
RIRs allocate IPs to organizations, Internet service providers (ISPs), or, in
some cases, National Internet Registries (NIRS) or Local Internet Registries
Taiwan’s ISPs get their IPs from TWNIC:
NIR of Taiwan: TWNIC http://www.twnic.net.tw/ip/ip_01.htm
LIRs/ISPs List of Taiwan: http://www.twnic.net.tw/english/ip/ip_03.htm.
Currently there are five Regional Registries, four active
and one in observer status.
APNIC ( http://www.apnic.net ) Asia-Pacific region.
ARIN ( http://www.arin.net ) North and South America, subSahara Africa regions.
LACNIC ( http://www.lacnic.net ) Latin America and portions
of the Caribbean
RIPE ( http://www.ripe.net ) Europe, parts of Asia, Africa north
of the equator, and the Middle East regions.
AfriNIC ( http://www.afrinic.net, currently in ”observer status” )
– allocate IP address blocks to
the five RIRs – allocate IPs to
Organizations, ISPs, or NIRs, or LIRs.
-- [Eduardo Sztokbant]
3 entities involved in Internet domain name
registration within this model:
Registrant: final client, the one who wishes to
register the domain name.
Registry: the operators that maintain the list of
available domain names within their extension.
Registrar: interface between registry and
registrant, may provide extra services to the
Relationship among the three Rs
While there can be several registrars that provide domain
registration and related services for a same given TLD,
there's necessairly only ONE authoritative repository
responsible for this TLD.
Reviews and develops recommendations on domainname policy for all generic top-level domains (gTLDs)
and advises the ICANN Board on these matters.
However, GNSO is not responsible fro domain-name
registration, but rather is responsible for the generic top-level
domains (for example, .com, .net, .edu, .org, and . info),
which can be found at http://www.iana.org/gtld/gtld.htm .
root name servers: http://www.gnso.icann.org/gtldregistries/
TLDR for .edu
TLDR for .org
TLDR for .com
Verisign Global Registry Service
Reviews and develops recommendations on domainname policy for all country-code top-level domains
(ccTLDs) and advises the ICANN Board on these
Again, ICANN does not handle domain-name registrations.
The definitive list of country-code top-level domains can be
found at http:// www.iana.org/cctld/cctld-whois.htm
.tw domain name is managed by TWNIC:
TLDR for .uk
TLDR for .ca
TLDR for .tw
Some Other Useful Links
IP v4 allocation: http://www.iana.org/assignments/ipv4address-space .
IP address services: http://www.iana.org/ipaddress/ipaddresses.htm .
Special-use IP addresses: http://www.rfceditor.org/rfc/rfc3330.txt .
Registered port numbers:
WHOIS Servers and Protocol
Essentially, the WHOIS is a database of
contact information about domain name
registrants. It is accessed through the
websites of registrars or registries, as well
as through technical means by the registrars
and registries, themselves.
Methods to Store WHOIS Information
There are two ways that WHOIS
information may be stored: Thick or Thin.
Thick model: one WHOIS server stores the
WHOIS information from all the registrars
for the particular set of data (so that one
WHOIS server can respond with WHOIS
information on all .org domains, for
Thin model: one WHOIS server stores the
name of the WHOIS server of a registrar
that has the full details on the data being
looked up (such as the .com WHOIS
servers, which refer the WHOIS query to
the registrar that the domain was registered
Availability of WHOIS Servers
The WHOIS query syntax, type of permitted queries,
available data, and the formatting of the results can vary
widely from server to server.
Many of the registrars are actively restricting queries to
combat spammers, attackers, and resource overload.
Information for .mil and .gov have been pulled
from public view entirely due to national security
Information for .edu.tw is not available in .tw
domain registry—TWNIC ( http://rs.twnic.net.tw/ .)
Problems with WHOIS Servers
Privacy: Registrant’s contact details.
Lack of WHOIS server lists.
Domain-Related vs. IP-Related
Domain-related items (such as osborne.com)
are registerd separately from IP-related items
(such as IP net-blocks).
Therefore, we will have two different paths in our
methodology for finding these details.
Domain - Related Search
The authoritative Registry for a given TLD, e.g.
com, contains information about which registrar
the target entity registered its domain with.
By querying the appropriate Registrar, the
Registrant details for the particular domain name
can be found.
The above steps are referred to as the “Three Rs”
of WHOIS– Registry, Registrar, Registrant.
Exmaple for tsmc.com
IANA Whois service
Result: Registry VeriSign Global Registry Services
VeriSign Global Registry Services Whois Service
Result: Registrar NETWORK SOLUTIONS, LLC.
NETWORK SOLUTIONS, LLC.Whois Service
Result: Registrant TSMC
Exmaple for uni-president.com.tw
IANA Whois service
Result: Registry Taiwan Network Information Center (TWNIC)
Registrar Taiwan Network Information Center (TWNIC) Whois Service
Result: Registrant 統一企業股份有限公司
P.S.: TWNIC is also the Registrar of com.tw
One-Stop-Shopping for WHOIS
IP-Related Search (1)
The WHOIS server at ICANN (IANA) does not
currently act as an authoritative registry for all the
RIRs as it does for the TLDs, but each RIR does
know which IP ranges it manage. This allows us
to simply pick any one of them to start our search.
If we pick the wrong one, it will tell us which one
e need to go to.
IP-Related Search (2)
You are interested in the IP address 188.8.131.52.
Try the WHOIS search at RIR ARIN’s web site.
The result shows that the IP address is managed by
Then go to RIR APNIC’s web site to search the same
Here you are.
The above process can be followed to trace back any IP
address in the world to its owner, or at least to a point of
contact that may be willing to provide the remaining
Laundered IP addresses: an attacker can also masquerade
her/his true IPs.
IP-Related Search (3)
We can also find out IP ranges and BGP autonomous
system numbers that an organization “owns” by searching
the RIR WHOSI servers for the organization’s literal name.
E.g. go to http://whois.apnic.net and type ncu.
• TWNIC doesn’t provide detailed information; therefore no
detailed information are shown.
E.g. go to http://www.arin.net and type Google.
• Useful information:
Administrators’ names: could be used to cheat gullible users to
change their passwords.
Phone and fax number
DNS names: could be used in DNS interrogation.