Lan: Ethernet, Token Ring, ARCNet og FDDI.
  Wan: Serial lines, Packet switched networks.
 

ARP: (Adress Resolution Protocoll):

Before communication between two hosts can occur, the IP address of each host must be resolved to the host`s hardware address.

 Kommando: ARP.EXE   (...\systemroot\system32)

Registry: ARP Cache Life: Setter tiden for caching av Mac-adresse.
 

ICMP: (Internet Controll Message Protocol):

- Rapporterer feil og kontrollerer beskjeder.
 
 

IGMP: (Internet Group Management Protoco):

Internet Group Management Protocol, informs routers that hosts of a specific mulitcast group are available on a given network. This information is passed to other routers so that each other router that supports mulitcasting is aware of witch hosts group are on which network.

FORSKJELLIGE TYPER NETTVERKSPAKKER:

- UNICAST:   Til en maskin.
- BROADCAST:  Til alle maskiner på samme fysiske nett.
- MULTICAST: Til grupper av maskiner.
 

IP (Internet Protocol):

- Addresses and routes packets.
- Connectionless – Non sessions is etablished.
- Nonguaranted ”Best effort” Delivery.
- Relabillity is the responsibility or higher-layer protocol and applikations.
- Fragments and Reasembles packets.
 

IP on the Router:

- Decrements the TTL (Time to live)   Standard 128 i NT 4.0
- Fragments large packets into smaler packets.
- Creates a new header for each new packet. (FLAG, FRAGMENT ID, FRAGMENT OFFSET).
- Calculates a new chechsum.
- Obtains the hardware address of the next router.
- Forwards the packets.

PORTS & SOCKETS:

 Port: Indentifiserer tjeneste.

 Sockets: Informasjon om hvem man kommuniserer med. (Port + IP adresse)
                Identifiserer hvordan tjenesten skal kommuniseres.

Portnummer kan finnes under:  ...\\SYSTEMROOT\SYSTEM32\DRIVERS\ETC\SERVICES
 

TCP: Transmission Controll Protocoll:

- Connection-oriented (Session established before exchanging data)
- Reliable delivery.
- Byte stream communications.
- Uses portnumbers as endpoints to communicate.

  TCP-Porter:    21 – FTP
    23 – TELNET
    53 – DNS
  139 – NetBios Session Service.
 

TCP-Sliding-Windows: TCP uses sliding windows to buffer data for transmissions between two hosts. TCP/IP hosts maintains two sliding windows: One for receiving data, and the other
for sending data. The size indicates the amount of data that can be buffered on a computer.

      Registry:  TCPWINDOWSSIZE   (Kan endres).

IP ADDRESS GUIDELINES:

- Network ID kan ikke være 127, fordi 127 er reservert for ”lookback-funksjoner”.
- Network ID og Host ID kan ikke være 255 (All bits set to 1) fordi 255 er broadcast adresse.
- Network ID og Host ID kan ikke være 0 (All bits set to 0) fordi 0 betyr kun dette nett.
- Host ID må være unik på nettet.
 

SUBNET MASK: Skiller Network ID fra Host ID.
   Benyttes for å spesifisere om ”destination” host er lokal eller remote.
 

Local and Destination hosts subnet masks are ”AND`ed”:

 1 and 1 = 1
 Other  combinations = 0

Hvis AND`ed resultat av soruce og destination hosts matcher, så er destination lokal.
 

EKS:      Egen IP adresse:  131.107.2.200
    Maske   255.255.0.0
    Nett:    131.107.0.0
 

IP ADDRESSING WITH IP v.6: Expanded addressing capabilities.
     Simplified header format.
     Support for time-depended options.
     Support for IP header extensions for future technologies.

     IP v.6 has 128-bits source and destination IP address, 4 times larger than IP v.4.

SUBNET:

- Mix different technologies, such as Ethernet og Token Ring.
- Overcome limitations of current technologies, such as exceeding the maximum number of hosts per segment.
- Reduce network congestion by redirecting traffic and reducing broadcasts.
 

IP ROUTING: Routing is the process of choosing a path over which to send packets. Routing occurs at a TCP/IP host when it sends IP packets and routing occurs at an IP Router.

STATIC vs DYNAMIC IP ROUTING:

 Static:       -    Routers do not share routing information.
- Routing tables are built manually.
- Microsoft supports multihomed systems as routers.

Dynamic: -    Routers share routing information automaticly.
- Routing tables are built dynamicly.
- Requires a routing protocoll such as RIP.
- Microsoft supports RIP for IP and IPX/SPX.

DEAD GATEWAY DETECTION:

TCP can detect faliure of the gateway and make the necessary adjustment to the IP routing table to use another default gateway configured on a computer utill it recives an acknowledgement. However, if one half of the TCPMAXDATARETRANSMISSIONS-value is exceeded and multiple gateways are configured on the computer, TCP requests that IP switch to the next default gateway in the list.

When you configure a computer running Windows NT with the IP-address of multiple gateways, by default, dead gateway detection is set to ON.
 

STATIC ENTRIES: Kommando:  ROUTE

  eks:  ROUTE ADD [Network] mask [Netmask] [Gateway]   (Adds a route)

          ROUTE PRINT           (Viser routingtable)
 
 

TRACERT-Utillity: Verifies the route taken to a destination host.
Useful for isolating routers and WAN-links that are slow og not functioning.

   Kommando:  TRACERT IPADDRESS.

DHCP: Dynamic Host Configuration Protocol:

BOOTP enables diskless clients to start up and automatically configure TPC/IP. The DHCP is an extension of the BOOTP-protocol. DHCP centralizes and manages the allocation of TCP/IP configuration information by automatically assigning IP addresses to computers configured to use DHCP. Implementing DHCP eliminates som of the configuration problems associated with manually configuring TCP/IP.
 

Each time a DHCP client starts, it requests IP addressing information from a DHCP server, including:
IP address, Subnet Mask, otional values such as default gateway, address, DNS –address and NetBios Name Server Address.
 

IPCONFIG-utillity: IPCONFIG /ALL  viser:  Windows NT  IP-konfig.
      Nettverksadapter IP-konfig.

  IPCONFIG /RENEW: Henter oppdaterte valg og fornyer ”lease-time”

  IPCONFIG /RELEASE: Frigjør IP-konfigurasjonen.
 

DHCP-database: DHCP.MOB Databasefilen til DHCP.

DHCP.TMP Temperær fil som DHCP lager mens DHCP service kjører.

JET.LOG og JET*.LOG Logg over alle tranaksjoner via DHCP-databasen. Disse kan benyttes for restore av DHCP, hvis nødvendig.

NETBIOS OVER TCP/IP: -     Network name registration and verification.
- Session establishment and termiantion.
- Reliable connection-oriented session-data-transfer.
- Unreliable connectionless datagram-data-transfer.
- Support protocol (driver) and adapter monitoring and management.
 

Hva er NetBios-navn: * Adresse (16 byte) som unikt identifiserer en prosess for netverkskommunikasjon.

   * Benyttes av alle Windows NT nettverkstjenester for unikt å identifisere dem selv.

 * NetBios-navn benyttes ikke av TCP/IP.

FINNES UNDER: Properties + TCP/IP Protocol + WINS-address:   SCOPE ID: _____
 
 

NETBIOS NAME RESOLUTION: Prosessen av mapping av NetBios-navn til en IP-adresse.

 Microsoft-metoder:   LMHOSTS-fil, HOSTS-fil og Domain Name System (DNS).
 
 

NBTSTAT-utillity:  This utillity checks the state of the current NetBios over TCP/IP connections, updates the LMHOSTS-CACHE, and determins your registred name and scope ID.
 

 NBTSTAT –n Lists the NetBios name cache.

 NBTSTAT –c Displays NetBios name cache.

NBTSTAT –R Manually reloads the NetBios cache using entries in the LMHOSTS-file with a #PRE-parameter.
 

NAME RESOLUTION USING LMHOSTS:

LMHOSTS is a static file used to resolve NetBios namees/IP-addresses of remote Windows NT based computers
and other NetBios-based hosts.

PREDEFINED KEYWORDS: #PRE  Defines which entries should be initially preloaded as       permanent entries in the name cache.

#DOM:[domain_name]Facilitates domain activity, such as logon validation over a router, account syncronization and browsing.

#INCLUDE Loads and searches NetBios entries in a separate
 file form the default LMHOSTS-file. Typically a
 #INCLUDE file is a centrally located shared
 LMHOSTS-file.
 

WHY USE WINS: -    Requests are sendt to WINS-server directly. Reduces broadcast-trafic.
- The WINS-database is updated dynamically. No LMHOSTS-file is nesessary.
- Provides the abillity to browse. (WAN-resources and InterDomain-resources).
 

HOST NAME RESOLUTION:  (TCP/IP naming schemes)

 Windows NT: -IP addresses.
   -NetBios names.

 UNIX Environments: -IP addresses.
    -Host names
    -Domain names.
 

TROUBLESHOOTING DNS WITH NSLOOKUP-utillity: Primary troubleshooting tool for DNS.

 NSLOOKUP [[-option] [computer to find] – [server]]

MICROSOFT TCP/IP UTILLITIES: REXEC Run commands to UNIX host.

     RSH  Run commands to UNIX host.

     TELNET Terminal emulation.

     RCP  Bidirectional filetransfer.

     FTP  Bidirectional filetransfer over TCP.

     TFTP  Bidirectional filetransfer over UDP.

LPD Services LPR requests and submits print job to a print device.
     LPQ  Checks print queue status.
 

FTP-Kommandoen: (FTP)
   BINARY Changes the file transfer type to binary.
   GET  Copies a remote file to a local host.
   PUT  Copies a local file to a remote host.
   !  Temporarily puts you to command promt.
   QUIT/BYE Exits FTP.
   USER  Angi brukernavn.

SNMP (Simple Network Management Protocol): SNMP is a part of the TCP/IP protocol suite.
It was originally developed in the internet community to monitor and troubleshoot routers and bridges.

 SNMP provides the ability to monitor and communicate status information between:

  -Computers running Windows NT.
  -LAN manager servers.
  -Terminal servers.
  -Wiring hubs.

With the Microsoft SNMP-service, a Windows NT based computer can report its status to an SNMP management system on a TCP/IP network.