Kerio Tech KERIO WINROUTE FIREWALL 6 User Manual download pdf (Page 359)

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Ident

The Ident protocol is used for identiﬁcation of user who established certain TCP connec-

tion from a particular (multi-user) system. TheIdent service is used for example by IRC

servers, FTP servers and other services.

More information (in English) can be found for example at Wikipedia.

IMAP

Internet Message Access Protocol (IMAP) enables clients to manage messages stored on

a mail server without downloading them to a local computer. This architecture allows the

user to access his/her mail from multiple locations (messages downloaded to a local host

disk would not be available from other locations).

IP address

IP address is a unique 32-bit number used to identify the host in the Internet. It is spec-

iﬁed by numbers of the decimal system (0-255) separated by dots (e.g. 195.129.33.1).

Each packet contains information about where it was sent from (source IP address) and

to which address it is to be delivered (destination IP address).

IPSec

IPsec (IP Security Protocol) is an extended IP protocol which enables secure data transfer.

It provides services similar to SSL/TLS, however, these services are provided on a network

layer. IPSec can be used for creation of encrypted tunnels between networks (VPN) — so

called tunnel mode, or for encryption of traﬃc between two hosts— so called transport

mode.

Kerberos

Kerberos is a system used for secure user authentication in network environments. It was

developed at the MIT university and it is a standard protocol used for user authentication

under Windows 2000/2003/2008. Users use their passwords to authenticate to the central

server (KDC, Key Distribution Center) and the server sends them encrypted tickets which

can be used to authenticate to various services in the network. In case of the Windows

2000/2003/2008 domains, function of KDC is provided by the particular domain server.

LDAP

LDAP (Lightweight Directory Access Protocol) is an Internet protocol used to access di-

rectory services. Information about user accounts and user rights, about hosts included

in the network, etc. are stored in the directories.

NAT

NAT (Network Address Translation ) stands for substitution of IP addresses in packets

passing through the ﬁrewall:

• source address translation (Source NAT, SNAT) — in packets going from local

networks to the Internet source (private) IP addresses are substituted with the

external (public) ﬁrewall address. Each packet sent from the local network is

recorded in the NAT table. If any packet incoming from the Internet matches

with a record included in this table, its destination IP address will be substituted

by the IP address of the appropriate host within the local network and the packet

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Kerio Tech KERIO WINROUTE FIREWALL 6 User Manual Page 359