You can easily google for different version of this document.
As far as checking what that IP is. Best start by checking whois :-)
In this case it's verisign ... not sure why anyone would send UDP to it ... you might need to sniff traffic.
whois 198.41.0.4
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# Query terms are ambiguous. The query is assumed to be:
# "n 198.41.0.4"
#
# Use "?" to get help.
#
#
# The following results may also be obtained via:
# http://whois.arin.net/rest/nets;q=198.41.0.4?showDetails=true&showARIN=false&ext=netref2
#
NetRange: 198.41.0.0 - 198.41.3.255
CIDR: 198.41.0.0/22
OriginAS:
NetName: INTERNIC1
NetHandle: NET-198-41-0-0-1
Parent: NET-198-0-0-0-0
NetType: Direct Assignment
RegDate: 1993-01-04
Updated: 2005-01-13
Ref: http://whois.arin.net/rest/net/NET-198-41-0-0-1
OrgName: VeriSign Infrastructure & Operations
OrgId: VIO-2
Address: 12061 Bluemont Way
City: Reston
StateProv: VA
PostalCode: 20190
Country: US
RegDate: 2002-07-11
Updated: 2012-01-03
Ref: http://whois.arin.net/rest/org/VIO-2
OrgAbuseHandle: NETWO480-ARIN
OrgAbuseName: Network Admin
OrgAbusePhone: +1-703-948-4300
OrgAbuseEmail: netadmin@verisign.com
OrgAbuseRef: http://whois.arin.net/rest/poc/NETWO480-ARIN
OrgTechHandle: NETWO480-ARIN
OrgTechName: Network Admin
OrgTechPhone: +1-703-948-4300
OrgTechEmail: netadmin@verisign.com
OrgTechRef: http://whois.arin.net/rest/poc/NETWO480-ARIN
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# ARIN WHOIS data and services are subject to the Terms of Use
# available at: https://www.arin.net/whois_tou.html
#