1. Inleiding computersystemen en netwerken deel 2 Hogeschool van Utrecht / Institute for Computer, Communication and Media Technology 5.1

2. Inleiding computersystemen en netwerken deel 2 Hogeschool van Utrecht / Institute for Computer, Communication and Media Technology 5.2 Mogelijkheden van netwerken Fileserver-systems Remote execution / log-on Distributed systems Resource sharing (printer, scanner) Document sharing (WWW) Mail News Voice

3. Inleiding computersystemen en netwerken deel 2 Hogeschool van Utrecht / Institute for Computer, Communication and Media Technology 5.3 Protocollen The Point-to-Point Protocol (PPP) Telnet TCP/IP IPX/SPX Novell NFS RPC X-25 X-window Apple talk Netbeui An agreed-upon format for transmitting data between two devices.

4. Inleiding computersystemen en netwerken deel 2 Hogeschool van Utrecht / Institute for Computer, Communication and Media Technology 5.4 Novell, IPX / SPX IPX : Internetworking Packet Exchange SPX : Sequence Packet Exchange SPX ligt bovenop IPX en wordt dus ingekapseld in IPX!

5. Inleiding computersystemen en netwerken deel 2 Hogeschool van Utrecht / Institute for Computer, Communication and Media Technology 5.5 IPX-header

6. Inleiding computersystemen en netwerken deel 2 Hogeschool van Utrecht / Institute for Computer, Communication and Media Technology 5.6 SPX-header

7. Inleiding computersystemen en netwerken deel 2 Hogeschool van Utrecht / Institute for Computer, Communication and Media Technology 5.7 Eenvoudig MS-DOS netwerk (LAN)

8. Inleiding computersystemen en netwerken deel 2 Hogeschool van Utrecht / Institute for Computer, Communication and Media Technology 5.8 TCP / IP TCP : Transmission Control Protocol Whereas the IP protocol deals only with packets, TCP enables two hosts to establish a connection and exchange streams of data. TCP guarantees delivery of data and also guarantees that packets will be delivered in the same order in which they were sent. IP : Internet Protocol. IP specifies the format of packets, also called datagrams (soort brievenpost), and the addressing scheme. (de iplaag verzorgt de routering)

9. Inleiding computersystemen en netwerken deel 2 Hogeschool van Utrecht / Institute for Computer, Communication and Media Technology 5.9 IP-header

10. Inleiding computersystemen en netwerken deel 2 Hogeschool van Utrecht / Institute for Computer, Communication and Media Technology 5.10 IP-adres

11. Inleiding computersystemen en netwerken deel 2 Hogeschool van Utrecht / Institute for Computer, Communication and Media Technology 5.11 IP-adres op het internet Class A - supports 16 million hosts on each of 126 networks Class B - supports 65,000 hosts on each of 16,000 networks Class C - supports 254 hosts on each of 2 million networks An IP address consists of two parts, one identifying the network and one identifying the node, or host. The Class of the address determines which part belongs to the network address and which part belongs to the node address

12. Inleiding computersystemen en netwerken deel 2 Hogeschool van Utrecht / Institute for Computer, Communication and Media Technology 5.12

13. Inleiding computersystemen en netwerken deel 2 Hogeschool van Utrecht / Institute for Computer, Communication and Media Technology 5.13 Niet routeerbare adressen BeginadresEindadres 10.0.0.010.255.255.255 172.16.0.0172.31.255.255 192.168.0.0192.168.255.255 127.0.0.0127.255.255.255loopback

14. Inleiding computersystemen en netwerken deel 2 Hogeschool van Utrecht / Institute for Computer, Communication and Media Technology 5.14 TCP-header Het poort nummer is gekoppeld aan een bepaalde applicatie. Poort 80 wordt bijv. gebruikt voor http verkeer.

15. Inleiding computersystemen en netwerken deel 2 Hogeschool van Utrecht / Institute for Computer, Communication and Media Technology 5.15 UDP (Universal Datagram Protocol)

16. Inleiding computersystemen en netwerken deel 2 Hogeschool van Utrecht / Institute for Computer, Communication and Media Technology 5.16 Protocol stack voor TCP/IP FTP via poort 21, HTTP via 80, telnet via 23, NNTP via 119, SMTP via 25 (zie /etc/services op een linuxmachine voor een lijst met standaard poortnummers )

17. Inleiding computersystemen en netwerken deel 2 Hogeschool van Utrecht / Institute for Computer, Communication and Media Technology 5.17 Voorbeeld van ping bekeken met Ethereal

18. Inleiding computersystemen en netwerken deel 2 Hogeschool van Utrecht / Institute for Computer, Communication and Media Technology 5.18 En een ping wat verder weg naar 145.89.166.36

19. Inleiding computersystemen en netwerken deel 2 Hogeschool van Utrecht / Institute for Computer, Communication and Media Technology 5.19 En nu als ping www.expa.hvu.nl

20. Inleiding computersystemen en netwerken deel 2 Hogeschool van Utrecht / Institute for Computer, Communication and Media Technology 5.20 Eenvoudig netwerk met router ARP : Address Resolution Protocol, a network layer protocol used to convert an IP address into a physical address (Data Link Control address or MAC address). DHCP : Dynamic Host Configuration Protocol, a protocol for assigning dynamic IP addresses to devices on a network. ethernet, MAC address

21. Inleiding computersystemen en netwerken deel 2 Hogeschool van Utrecht / Institute for Computer, Communication and Media Technology 5.21 IP versie 6 Internet Protocol next generation adres 128 bits = 16 bytes bijv. 2001:07b8:0:0:0:0:0:1 = 2001:7b8::1 poort 80 op dit adres schrijf je als [2001:7b8::1]:80

22. Inleiding computersystemen en netwerken deel 2 Hogeschool van Utrecht / Institute for Computer, Communication and Media Technology 5.22 V: 4-bit Internet Protocol version number = 6. Prio: 4-bit Priority value. Flow Label: 24-bit field, Quality of Service. Payload Length: 16-bit unsigned integer. Length of payload, i.e., the rest of the packet following the IPng header, in octets. Next Hdr: 8-bit selector. Identifies the type of header immediately following the IPng header. Hop Limit: 8-bit unsigned integer. Decremented by 1 by each node that forwards the packet. The packet is discarded if Hop Limit is decremented to zero. Source Address: 128 bits. Destination Address: 128 bits.

23. Inleiding computersystemen en netwerken deel 2 Hogeschool van Utrecht / Institute for Computer, Communication and Media Technology 5.23 RPC : Remote Procedure Call

24. Inleiding computersystemen en netwerken deel 2 Hogeschool van Utrecht / Institute for Computer, Communication and Media Technology 5.24 DCE : Distributed Computing Environmernt Suite of technology services developed by The Open Group for creating distributed applications that run on different platforms.

25. Inleiding computersystemen en netwerken deel 2 Hogeschool van Utrecht / Institute for Computer, Communication and Media Technology 5.25 COM, DCOM, CORBA, RMI COM : Component Object Model, DCOM : Distributed COM (Microsoft) CORBA : Common Object Request Broker Archticture (Open Source) RMI: Remote Method Invocation (Java) The COM software architecture is developed by Microsoft to build component-based applications. COM objects are discrete components, each with a unique identity, which expose interfaces that allow applications and other components to access their features.

26. Inleiding computersystemen en netwerken deel 2 Hogeschool van Utrecht / Institute for Computer, Communication and Media Technology 5.26 LDAP LDAP : Lightweight Directory Access Protocol, a set of protocols for accessing information directories. OpenLDAP is the Open Source Version of LDAP LDAP should eventually make it possible for almost any application running on virtually any computer platform to obtain directory information, such as email addresses and public keys.

27. Inleiding computersystemen en netwerken deel 2 Hogeschool van Utrecht / Institute for Computer, Communication and Media Technology 5.27 Security by Encryption (not by Obscurity!) Encryption techniques are based on public and private key’s. Examples: GPG (GNU Pretty Good privacy for files and email) SSL (Secure Socket Layer - on application level) TLS (Transport Layer Security - on application level) IPSec (IP Secure – on IP level) SSH (Secure Shell protocol)

28. Inleiding computersystemen en netwerken deel 2 Hogeschool van Utrecht / Institute for Computer, Communication and Media Technology 5.28 Internet en intranet (achter firewall) E-mail FTP Telnet News WWW SSH Bovenop TCP/IP: A global network connecting millions of computers. More than 100 countries are linked into exchanges of data, news and opinions.

29. Inleiding computersystemen en netwerken deel 2 Hogeschool van Utrecht / Institute for Computer, Communication and Media Technology 5.29 Opdracht bestudeer 15.8 t/m 15.10 Practicum Ethereal