User Manual

Page 107
Rule Name : Enter a unique name to identify this firewall rule.
Disposition
Policy
: This parameter determines whether the packets obeying
the rule should be accepted or denied by the firewall.
Choose between Accept and Deny.
Protocols : Users are allowed to select the type of data packet from:
TCP, UDP, ICMP, IGMP or ALL.
Note: If users select either ICMP or IGMP, they are
required to make further selection in the ICMP Types or
IGMP Types respectively.
ICMP Types : This IP protocol is used to report errors in IP packet routing.
ICMP serves as a form of flow control, although ICMP
messages are neither guaranteed to be received or
transmitted.
ICMP
Packet Type
Description
Echo
request
Determines whether an IP
node (a host or a router) is
available on the network.
Echo reply Replies to an ICMP echo
request.
Destination
unreachabl
e
Informs the host that a
datagram cannot be
delivered.
Source
quench
Informs the host to lower the
rate at which it sends
datagrams because of
congestion.
Redirect Informs the host of a
preferred route.
Time
exceeded
Indicates that the Time-to-
Live (TTL) of an IP datagram
has expired