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– The portion of a packet, preceding the actual data, containing source and destination information. It
Header
may also error checking and other fields. A header is also the part of an electronic mail message that precedes
the body of a message and contains, among other things, the message originator, date and time
– In client-server architectures, the computer on which the server software is running is called the host. It
Host
is possible for several servers to be running on one host, e.g. one FTP server and one email server. Hosts can
be accessed with the help of clients, e.g. with a browser or an email program. As the expression server is used
for the program (i.e. the software) as well as for the computer on which the program is running (i.e. the
hardware), server and host are not clearly separated in practice. In data telecommunication the computer from
which information (such as FTP flies, news, www pages) is fetched, is called the host. A host is also called a
node in the Internet. Using an Internet host (as opposed to a local host), it is possible to work from a distance
(remote access).
– A computer that allows users to communicate with other host computers on a network. Individual users
Host
communicate by using application programs, such as electronic mail, Telnet, and FTP.
– Secure HyperText Transfer Protocol, a secure way of transferring information over the
HTTPS (aka, S-HTTP)
World Wide Web. HTTPS refers to the entry (e.g., https://192.168.2.100) used for an S-HTTPS connection. S-
HTTPS is the IETF RFC that describes syntax for securing messages sent using the Hypertext Transfer
Protocol (HTTP), which forms the basis for the World Wide Web. S-HTTP provides independently applicable
security services for transaction confidentiality, authenticity/integrity and non-reputability of origin. S-HTTP
emphasizes maximum flexibility in choice of key management mechanisms, security policies and cryptographic
algorithms by supporting option negotiation between parties for each transaction.
– The Internet Control Message Protocol notifies the IP datagrams sender about abnormal events.
ICMP
ICMP might indicate, for example, that an IP datagram cannot reach an intended destination, cannot connect to
the requested service, or that the network has dropped a datagram due to old age. ICMP also returns
information to the transmitter, such as end-to-end delay for datagram transmission.
IETF (Internet Engineering Task Force)
protocol and most of the other successful protocols used on the Internet. The IETF web page is at
http://www.ietf.org/.
– The Internet Protocol (IP) is the basic protocol for the transmission of Internet information. It has been in
IP
use virtually unchanged since 1974. It establishes and ends connections, as well as recognizing errors. By
using NAT and Masquerading, private networks can be mapped onto official IP addresses. This way, the Ipv4
address space will still last a long time. Standard Internet open protocols include:
Protocol
TCP/IP
HTTP
NFS
IMAP4/SMTP
DNS
DNS/LDAP
Bootp/DHCP
SNMP
– A 32-bit number that identifies the devices using the IP protocol. An IP address can be unicast,
IP Address
broadcast, or multicast. See RFC 791 for more information. Every host has a clear IP address, comparable
with a telephone number. An IP address consists of four decimal numbers between 1 and 254 divided by dots
(e.g., a possible IP address is 212.6.145.0. At least one name of the form xxx belongs to every IP address
(e.g. xxx). This defines a computer with the name ox that is in the sub domain xxx of the sub domain xxx of the
domain xxx. Like with IP addresses, the individual name parts are divided by dots. However, as opposed to IP
addresses, IP names are not limited to four parts. Also, several IP names can be assigned to one IP address;
these are referred to as aliases.
– The part of the IP packet that carries data used on packet routing. The size of this header is 20
IP Header
bytes, but usually the IP options following this header are also calculated as header. The maximum length of
the header is 60 bytes. The header format is defined in RFC 791.
MultiAccess Communications Server MA30120 User Guide
– The international standards body that has standardized the IP
Function
basic network communication
browsing
File Service
Mail Service
Naming Service
Directory Services
Booting Services
Network Administration
Glossary
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