3Com 3032 Configuration Manual page 557

Table 620 Mnemonic Symbol of the ICMP Message Type
Operator and Syntax
echo
echo-reply
fragmentneed-DFset
host-redirect
host-tos-redirect
host-unreachable
information-reply
information-request
net-redirect
net-tos-redirect
net-unreachable
parameter-problem
port-unreachable
protocol-unreachable
reassembly-timeout
source-quench
source-route-failed
timestamp-reply
timestamp-request
ttl-exceeded
By configuring the firewall and adding appropriate access rules, you can use
packet filtering to check IP packets that pass the router. The passing of unexpected
packets can thus be prohibited. In this way the packet filtering helps to protect the
network security.
Configure the match sequence of access control list
An access control rule can be composed of several "permit" and "deny"
statements and the range of the data packet specified by each statement varies.
The match sequence needs to be configured when matching a data packet and
access control rule.
The maximum number of rules configured under an acl-number is 500 (that is,
500 rules can be configured in normal time range, and 500 rules can also be
configured in special time range), and the number of total rules under all
acl-number are not more than 500. When there is a conflict among several rules,
the system will configure the match rules according to the following principle:
Rules with the same serial number can be defined. If two rules with the same
serial number conflict, use the "depth-first" principle to judge the source-addr,
source-wildcard-mask, destination-addr, destination-wildcard-mask, protocol
number and port number, then determine the sequence of the rule.
If the ranges defined by the rules are the same, then determine the sequence
of the rules according to the time sequence of definition. The system will
choose the rule defined earlier.
Firewall Overview
Meaning
Type=8, Code=0
Type=0, Code=0
Type=3, Code=4
Type=5, Code=1
Type=5, Code=3
Type=3, Code=1
Type=16,Code=0
Type=15,Code=0
Type=5, Code=0
Type=5, Code=2
Type=3, Code=0
Type=12,Code=0
Type=3, Code=3
Type=3, Code=2
Type=11,Code=1
Type=4, Code=0
Type=3, Code=5
Type=14,Code=0
Type=13,Code=0
Type=11,Code=0
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