Eicon Networks 1550 - Manual (Page 67)

Security 67
Source / Destination
• ‘from’: Examine the source IP address of the datagram.
• ‘to’: Examine the destination IP address of the datagram.
Location
• ‘the Ethernet LAN’: Sets the filter to match datagrams with network addresses that
are the same as that of the Eicon 1550/1551. By default, this is 192.168.1.0. A mask
of 255.255.255.0 is used to extract the network address.
• ‘the network’: Sets the filter to match datagrams with network addresses that are the
same as the one you specify. Choosing this option requires that you supply the IP
address of a class C network in the next box. The filter uses a mask of 255.255.255.0
to extract the network address (class C network mask).
• ‘host’: Sets the filter to match datagrams with IP addresses that are the same as the
one you specify. Choosing this option requires that you supply the IP address of the
host computer in the next box. The filter uses a mask of 255.255.255.255.
• ‘anywhere’: Sets the filter to ignore the source and destination address in the
datagram.
Address
• ‘Address’: Only applies if you select the network or the host for location.
Protocol
IP datagrams can carry a wide variety of protocol traffic. The Eicon 1550/1551 lets you
filter many of the most popular protocols. The following descriptions explain some of
the options that are available.
• ‘any’: Applies the filter to any datagram.
• ‘any well known’: Applies the filter to any protocol using TCP or UDP ports in the
range 0 to 1023. See RFC 1700 for the complete list of protocols.
• ‘UNIX’: Applies the filter to any protocol using TCP or UDP ports in the range 512 to
1023. See RFC 1700 for the complete list of protocols.
• ‘TCP’: Many protocols (such as HTTP, FTP, Telnet, News) make use of TCP. If you
filter all TCP traffic you will prevent the use of these protocols. Note that access to
the web configuration interface occurs via HTTP and access to the command line
interface (CLI) occurs via Telnet.
• ‘UDP’: Many protocols (such as SNMP, Time, TFTP, BOOTP) make use of UDP. If
you filter all UDP traffic, you will prevent the use of these protocols.
• ‘FTP’: Applies the filter to all datagrams containing the file transfer protocol.
• ‘Web (HTTP)’: If you filter all HTTP traffic, you may not be able to reach the web
configuration interface. Filtering outgoing HTTP traffic can be used to prevent users
from browsing on the Internet.
• ‘Mail (SMTP)’: Applies the filter to all datagrams containing the mail (SMTP) protocol.
• ‘Mail (POP3)’: Applies the filter to all datagrams containing the mail (POP3) protocol.
• ‘Telnet’: If you filter all Telnet traffic, you will not be able to reach the command line
interface (CLI).