Name Resolution in Windows Server 2008 (R2)

Name Resolution Overview  NetBIOS name resolution  Host name resolution  Peer Name Resolution

Name Resolution Overview  NetBIOS name resolution * Originally a broadcast-based NR protocol in PC-LAN & LM networks on top of NetBEUI * Based on single-label names (non-hierarchical) * Uses lmhosts (static) files, broadcasts and WINS (NBNS) servers in TCP/IP networks  Host name resolution * Original ARPANET (Internet) NR protocol * Based on multi-level names (hierarchical) * Distributed database model * Uses hosts (static) files and DNS Servers

Name Resolution Overview  Peer Name Resolution * Strictly for IPv6 addresses * Distributed and serverless protocol * Real-time updates * Adresses computers, ports and services * Unsecured or secured with PK-cryptography

Protocol stack comparison P A D N T S P NetBIOS Interface WinSock Interface LLC MAC NetBEUI (NBF) SMB SMB, CIFS, HTTP TCP UDP IP medium ARP, PPP, xDLC 802.n Broadcast NR Traffic Unicast NR Traffic medium 802.n

Protocol stack comparison P A D N T S P NetBIOS Interface WinSock Interface LLC MAC SMB SMB, CIFS, HTTP TCP UDP IP medium ARP, PPP, xDLC 802.n Broadcast NR Traffic Unicast NR Traffic NBT NetBIOS over TCP/IP helper

Internet DNS Namespace “ root.com.edu.gov.int.mil.net.org “13” root-servers.net gTLD’s generic Top Level Domains.yale.ucla.mit.army.airforce.navy Second Level Domains Third Level Domains a.root-servers.net b.root-servers.net c.root-servers.net d.root.servers.net e.root-servers.net f.root-servers.net g.root-servers.net … l.root-servers.net m.root-servers.net

Internet DNS Namespace “ root.com.edu.gov.int.mil.net.org “13” root-servers.net gTLD’s generic Top Level Domains.yale.ucla.mit.army.airforce.navy Second Level Domains.math.physics.law Third Level Domains a.root-servers.net b.root-servers.net c.root-servers.net d.root.servers.net e.root-servers.net f.root-servers.net g.root-servers.net … l.root-servers.net m.root-servers.net

Internet DNS Namespace “ root.com.edu.gov.int.mil.net.org “13” root-servers.net gTLD’s generic Top Level Domains ISO 3166 country codes.be.de.jp.fr.nl.il.ru.tw.tv.nu.au.gb a.root-servers.net b.root-servers.net c.root-servers.net d.root.servers.net e.root-servers.net f.root-servers.net g.root-servers.net … l.root-servers.net m.root-servers.net

Internet DNS Namespace “ root.com.edu.gov.int.mil.net.org “13” root-servers.net gTLD’s generic Top Level Domains ISO 3166 country codes.be.de.jp.fr.nl.il.ru.tw.tv.nu.au.uk ccTLD’s Country code Top Level Domains a.root-servers.net b.root-servers.net c.root-servers.net d.root.servers.net e.root-servers.net f.root-servers.net g.root-servers.net … l.root-servers.net m.root-servers.net

m.root-servers.net l.root-servers.net k.root-servers.net j.root-servers.net i.root-servers.net h.root-servers.net g.root-servers.net f.root-servers.net e.root-servers.net d.root-servers.net c.root-servers.net b.root-servers.net a.root-servers.net Recursive query “ root.amazon.com “13” root-servers.net ? Root hints Own zone?No!… Cached? No!… Cached? No!… Ask my DNS server www

Iterative query “ root.amazon.com “13” root-servers.net ? Don’t know … ask.com server! amazon.com NS = ! Oh, it’s … ! www

Recursive response “ root.amazon.com “13” root-servers.net ? Don’t know … ask.com server! amazon.com NS = ! Oh, it’s … ! Ah, it’s … ! www

Recursive response “ root.amazon.com “13” root-servers.net ? www Cached: = TTL = 3600

Domain vs. Zone  Domain is a node in the Internet namespace  Root domain is largest domain  Zone is a file that contains records for a domain with or without child domains  Zones can only contain contiguous domains  Child domains can be delegated to separate DNS servers (=zone delegation)

Domain vs. Zone.arpa.int.gov.mil.com.net.edu.org.ccTLD’s.acme.amazon.bol.hp.microsoft.contoso.google.myspace.youtube.one.technet.msdn.mcp.update.support Root Domain.com Domain.microsoft Domain “.” (root)

Domain vs. Zone.arpa.int.gov.mil.com.net.edu.org.ccTLD’s.acme.amazon.bol.hp.microsoft.contoso.google.myspace.youtube.one.technet.msdn.mcp.update.support “.” (root)

Domain vs. Zone.com.microsoft.one.technet.msdn.mcp.update.support “.” (root) Single contiguous DNS zonefile contains all records for domains: microsoft.com one.microsoft.com technet.microsoft.com msdn.microsoft.com mcp.microsoft.com update.microsoft.com support.microsoft.com

Domain vs. Zone.com.microsoft “.” (root) DNS zonefile contains only records for: microsoft.com Delegated zones Each DNS server contains a separate zone for each delegation: one.microsoft.com technet.microsoft.com msdn.microsoft.com mcp.microsoft.com update.microsoft.com support.microsoft.com.one.technet.msdn.mcp.update.support

Partly delegated contiguous DNS zonefile contains records for: microsoft.com one.microsoft.com technet.microsoft.com msdn.microsoft.com mcp.microsoft.com Domain vs. Zone.com.microsoft.one.technet.msdn.mcp.update.support “.” (root) Delegated zones Each DNS server contains a separate zone for each delegation: update.microsoft.com support.microsoft.com

Partly delegated contiguous DNS zonefile contains records for: microsoft.com one.microsoft.com technet.microsoft.com msdn.microsoft.com mcp.microsoft.com Domain vs. Zone.com.microsoft.one.technet.msdn.mcp.update.support “.” (root) Illegal delegation Domains.update and.support are non-contiguous (common parent needed)

Zone types  Primary zone  Secondary zone  Stub zone  AD integrated zone (acts as primary zone)  RODC AD integrated zone (acts as primary Read-Only zone)

Primary Zone.com “.” (root) Primary Zone file contains R/W-version of data acme.com.dns acme.com IN SOA srv1.acme.com mail.acme.com Manual updates Automatic updates Refreshes ns1.acme.com ns2.acme.com pc1.acme.com pc2.acme.com pc3.acme.com acme

Secondary Zone Primary Zone file contains R/W-version of data acme.com.dns acme.com IN SOA srv1.acme.com mail.acme.com Manual updates Automatic updates Refreshes ns1.acme.com ns2.acme.com pc1.acme.com pc2.acme.com pc3.acme.com Secondary Zone file contains R/O-version of data.com “.” (root).acme

Secondary Zone Primary Zone file contains R/W-version of data Secondary Zone file contains R/O-version of data.com “.” (root).acme Request full zone transfer (AXFR) Authorized? … Yes! And Full Zone Transfer (AXFR)

DNS Notify Primary Zone file contains R/W-version of data Secondary Zone file contains R/O-version of data.com “.” (root).acme And Incremental Zone Transfer (IXFR) Update DNS Notify Database version increment Get SOA record Version increment = 1 IXFR (1 record) (send 1 record) Database version increment

Aging and Scavenging T0 Discover Offer Request Acknowledge Register DNS Request Acknowledge Register DNS Request Acknowledge Register DNS Tl 1 st No-Refresh IntervalRefresh Interval 2 nd No-Refresh Interval DHCP DNS Lease 0,5 Lease Renewed Lease 0,5 Lease Renewed Lease Zone file version: 1 2 3

Aging and Scavenging T0 Discover Offer Request Acknowledge Register DNS Tl 1 st No-Refresh IntervalRefresh Interval DHCP Lease 0,5 Lease Scavenging Interval DNS

Reverse Lookups  Resolve IP-addresses to FQDN’s  Reverse indexes the Internet  Uses the in-addr.arpa or ip6.arpa Domain  Requires participation of domain holders  Used for inbound SMTP server determination (and more)

Reverse Lookups  Compare: hostname structure  IP-address structure Srv3.east.acme.com. Internet root domain gTLD 2 nd Level domain 3 rd Level domain Hostname Left-to-right = Up the hierarchy

Reverse Lookups  Compare: hostname structure  IP-address structure Srv3.east.acme.com / Host-ID Net-ID Left-to-right = Down the hierarchy

Reverse Lookups  Compare: hostname structure  IP-address structure Srv3.east.acme.com / Host-ID Net-ID Left-to-right = Down the hierarchy

Reverse Lookups  Compare: hostname structure  IP-address structure Srv3.east.acme.com in-addr.arpa. “Host-ID” “Internet root” Left-to-right = Up the hierarchy

Reverse Lookups  Example IP-address  Find PTR in-addr.arpa.  Iterates between DNS servers to find: in-addr.arpa zone  Finds 201 PTR record with name: 201 IN PTR srv3.acme.com  Responsibility of acme.com domain holder to maintain PTR records

Reverse Lookups.int.gov.mil.in-addr.arpa.org.ccTLD’s … … “.” (root) 2 3 … … … … in-addr.arpa. acme.com IN SOA … 199 PTR srv1.acme.com 200 PTR srv2.acme.com 201 PTR srv3.acme.com 202 PTR srv4.acme.com … What name belongs to IP: ? srv3.acme.com ! 191. in-addr.arpa

Peer Name Resolution Protocol  Mentioned on P2P conference November 2001  July 2003: Advanced Networking Pack for XP  Later SP2 for XP  PNRP 2.0 in Windows Vista, available for XP  PNRP 2.1 in: * Windows Vista SP1 * Windows Server 2008 * Windows XP SP3 * Windows 7 Easy Connect (Remote Assistance)

Peer Name Resolution Protocol PNRP Clouds: A Cloud is a group of connected PNRP nodes (any node can resolve a name published by another node in the cloud) Three cloud scopes: 1.Global 2.Site Local (deprecated) 3.Link Local When starting PNRP service it joins multiple clouds Transient connectivity and shortcomings in DNS Easily scales to billions of names

 Peer name is a communications endpoint  Consists of Authority.Classifier (256 bits) P2P and PNRP ID’s e06bf33a5b21 … SHA-1.Friendly Name = P2P ID SHA-1 5ff01aac793c121f … (128 – bits hash) Service Location (128 – bits) = PNRP ID Authority Classifier 256 bits

 Peer name is a communications endpoint  Consists of Authority.Classifier (256 bits) P2P and PNRP ID’s e06bf33a5b21 … SHA-1.Friendly Name = P2P ID SHA-1 5ff01aac793c121f … (128 – bits hash) Service Location (128 – bits) = PNRP ID Authority Classifier 256 bits PNRP ID

 Authority = 0 if unsecure, value if secure P2P and PNRP ID’s PNRP ID Cache

End  Questions??