554
C
HAPTER
39: C
ONFIGURING
F
IREWALL
The “depth-first” principle means matching the access rules with the smallest
definition range of data packets. It can be achieved by comparing the wildcards of
address. The smaller the wildcards are, the smaller the range specified by the host
is. For example, 129.102.1.1.0.0.0.0 specifies a host (the address is 129.102.1.1),
while 129.102.1.1.0.0.255.255 specifies a network segment (the range of the
address is from 129.102.1.1 to 129.102.255.255), obviously the former is
arranged in the front of access control rule.
The special standard is the following:
■
For the statement of standard access control rules, compare the wildcards of
the source addresses directly, and arrange according configuration sequence if
the wildcards are the same.
■
For the access control rules based on interface filtering, the rules configured
with “
any
”are arranged last, and the rest will be arranged according to the
configuration sequence.
■
For extended access control rules, compare the wildcards of source addresses.
If they are the same, then compare the wildcards of the destination address. If
they are still the same, compare the range of port numbers, and the rule with
smaller range will be arranged first. If the port numbers are the same, then
match the rules according to the user's configuration sequence.
The
display acl
acl-number
command can be used to view the executive
sequence of the system access rules, and the rules listed ahead will be selected
first.
Configure Firewall
Firewall configuration includes:
■
Enabling and Disabling a Firewall
■
Configuring Standard Access Control List
■
Configuring Extended Access Control List
■
Setting the Default Firewall Filtering Mode
■
Configuring Special Timerange
■
Configuring Rules for Applying Access Control List on Interface
■
Specifying Logging Host
Enabling and Disabling a
Firewall
A firewall should be enabled for filtering messages to set other configurations into
effect.
Perform the following configurations in system view.
Table 621
Enable/Disable Firewall
Firewalls are disabled by default.
Operation
Command
Enable firewall
firewall enable
Disable firewall
firewall disable
Summary of Contents for 3036
Page 1: ...http www 3com com 3Com Router Configuration Guide Published March 2004 Part No 10014299 ...
Page 4: ...VPN 615 RELIABILITY 665 QOS 681 DIAL UP 721 ...
Page 6: ...2 ABOUT THIS GUIDE ...
Page 7: ...I GETTING STARTED Chapter 1 3Com Router Introduction Chapter 2 3Com Router User Interface ...
Page 8: ...4 ...
Page 16: ...12 CHAPTER 1 3COM ROUTER INTRODUCTION ...
Page 34: ...30 ...
Page 60: ...56 CHAPTER 3 SYSTEM MANAGEMENT ...
Page 98: ...94 CHAPTER 6 DISPLAY AND DEBUGGING TOOLS ...
Page 110: ...106 ...
Page 114: ...110 CHAPTER 8 INTERFACE CONFIGURATION OVERVIEW ...
Page 158: ...154 CHAPTER 10 CONFIGURING WAN INTERFACE ...
Page 168: ...164 ...
Page 188: ...184 CHAPTER 13 CONFIGURING PPPOE CLIENT ...
Page 192: ...188 CHAPTER 14 CONFIGURING SLIP Router ip route static 0 0 0 0 0 0 0 0 10 110 0 1 ...
Page 248: ...244 CHAPTER 16 CONFIGURING LAPB AND X 25 ...
Page 320: ...316 ...
Page 330: ...326 CHAPTER 20 CONFIGURING IP ADDRESS ...
Page 362: ...358 CHAPTER 21 CONFIGURING IP APPLICATION ...
Page 374: ...370 CHAPTER 23 CONFIGURING IP COUNT ...
Page 406: ...402 CHAPTER 25 CONFIGURING DLSW ...
Page 408: ...404 ...
Page 452: ...448 CHAPTER 29 CONFIGURING OSPF ...
Page 482: ...478 CHAPTER 30 CONFIGURING BGP ...
Page 494: ...490 CHAPTER 31 CONFIGURING IP ROUTING POLICY ...
Page 502: ...498 ...
Page 508: ...504 CHAPTER 33 IP MULTICAST ...
Page 514: ...510 CHAPTER 34 CONFIGURING IGMP ...
Page 526: ...522 CHAPTER 36 CONFIGURING PIM SM ...
Page 528: ...524 ...
Page 532: ...528 CHAPTER 37 CONFIGURING TERMINAL ACCESS SECURITY ...
Page 550: ...546 CHAPTER 38 CONFIGURING AAA AND RADIUS PROTOCOL ...
Page 590: ...586 CHAPTER 40 CONFIGURING IPSEC ...
Page 599: ...IX VPN Chapter 42 Configuring VPN Chapter 43 Configuring L2TP Chapter 44 Configuring GRE ...
Page 600: ...596 ...
Page 638: ...634 CHAPTER 43 CONFIGURING L2TP ...
Page 649: ...X RELIABILITY Chapter 45 Configuring a Standby Center Chapter 46 Configuring VRRP ...
Page 650: ...646 ...
Page 666: ...662 ...
Page 670: ...666 CHAPTER 47 QOS OVERVIEW ...
Page 700: ...696 CHAPTER 49 CONGESTION MANAGEMENT ...
Page 706: ...702 CHAPTER 50 CONGESTION AVOIDANCE ...
Page 707: ...XII DIAL UP Chapter 51 Configuring DCC Chapter 52 Configuring Modem ...
Page 708: ...704 ...
Page 762: ...758 CHAPTER 52 CONFIGURING MODEM ...