Operation Manual

NT/MPRI – Glossary 118
IP Addresses, see “TCP/IP Addresses” on page 123
IP Mask, see “TCP/IP Addresses” on page 123
IP-Masquerading / Network Address Translation (NAT)
One network, one IP address: With IP Masquerading, one “official” IP
address is sufficient for the communication between the private LAN
and the public Internet. The NT/MPRI processes the IP addresses in the
TCP, UDP and ICMP packets such that, effectively, only one IP address
is visible to the Internet. This means that these hosts of a private LAN
can use internal (“unofficial”) IP addresses for communication with the
Internet. It is considerable more difficult to break into a system protect-
ed in this way than it is to surmount a good packet-based firewall.
IPX (Internetworking Packet Exchange Protocol)
A network protocol developed by Novell with which data packets can
be exchanged quickly and reliably between two network computers.
IPX Addresses
A hexadecimal number identifying a server in a network. Each server
must have a unique internal IPX network number. This number consists
of eight hexadecimal digits (1 to FFFFFFFE). If several successive IPX ad-
dresses are to be compiled (e.g. when working with the RIP filter in the
NT/MPRI), a mask may be defined as well.
For example, to compile the successive IPX addresses 11111111 to
1111111F, enter the address as 11111110 and the mask as FFFFFFF0. To
compile the IPX addresses 11111110 to 11111113, enter the address as
11111110 and the mask as FFFFFFFC.
Keep-Alive Packets
Keep-alive packets are broadcast periodically to the entire network to
check whether a client is still active, for example. If the sending station
does not receive a reply, it discontinues the logical connection.
Logical ISDN Connection
A logical ISDN connection is created when the first physical ISDN con-
nection is set up and connection parameters are negotiated. These
connection parameters are valid for the duration of the logical ISDN
connection, and include the network protocol to be used, whether au-
thentication is to be carried out, and connection management parame-
ntmpri-e.book Seite 118 Donnerstag, 28. Februar 2002 11:26 11