User guide

Glossary
MultiAccess Communications Server MA30120User Guide 170
Hash – A one-way security function that takes an input message of arbitrary length and produces a fixed-
length digest. Used in SHA (Secure Hash Algorithm).
Header – The portion of a packet, preceding the actual data, containing source and destination information. It
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
Host – In client-server architectures, the computer on which the server software is running is called the host. It
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).
Host – A computer that allows users to communicate with other host computers on a network. Individual users
communicate by using application programs, such as electronic mail, Telnet, and FTP.
HTTPS (aka, S-HTTP) – Secure HyperText Transfer Protocol, a secure way of transferring information over the
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.
ICMP – The Internet Control Message Protocol notifies the IP datagrams sender about abnormal events.
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) – The international standards body that has standardized the IP
protocol and most of the other successful protocols used on the Internet. The IETF web page is at
http://www.ietf.org/
.
IP – The Internet Protocol (IP) is the basic protocol for the transmission of Internet information. It has been in
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
Function
TCP/IP basic network communication
HTTP browsing
NFS File Service
IMAP4/SMTP Mail Service
DNS Naming Service
DNS/LDAP Directory Services
Bootp/DHCP Booting Services
SNMP Network Administration
IP Address – A 32-bit number that identifies the devices using the IP protocol. An IP address can be unicast,
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.