Firewall Overview
549
Figure 171
Packet filtering schematic diagram
The following can be realized by data packet filtering:
■
Prohibit logging on with telnet from outside
■
Every E-mail is sent by SMTP (Simple Message Transfer Protocol).
■
One PC, rather than all other PCs, can send news to us by NNTP (Network
News Transfer Protocol).
Packet filtering in 3Com routers security equipment features the following:
■
Based on access-list (Access Control List - ACL): ACL is applied not only in
packet filtering but also in other features where data streams need to be
classified, such as address translation and IPSec.
■
Support standard and extended ACL: Set a simple address range with the
standard ACL or set the specific protocol, source address range, destination
address range, source port range, destination port range, priority and service
type with the extended ACL.
■
Support time segment: Set ACL functions in a specific period of time, such as
8:00-2:00 of every Monday, or it can be as specific as from a year/month/day to
another year/month/day.
■
Support ACL automatic sorting: You can select sorting ACLs of a specific
category to simplify the configuration and facilitate the maintenance.
■
It can be as specific as indicating the input/output direction: For example, a
special packet filtering rule can be applied in the output direction of the
interface that is connected with WAN or another packet filtering rule is applied
in the input direction.
■
Support interface based filtering: It can be set to prohibit or permit to forward
messages from a specific interface in a specific direction of an interface.
■
Support creating a log for message meeting the condition: Record the related
information of the message and provide a mechanism to guarantee that
excessive resources are not consumed when a large number of logs are
triggered in the same way.
Access Control List
To filter data packets, rules need to be configured. A rule identifies a packet to be
considered by an Access Control List.
The access control list is generally employed to configure the rules to filter data
packets, and the types of access control lists are as follows:
■
Standard access control list
Содержание 3036
Страница 1: ...http www 3com com 3Com Router Configuration Guide Published March 2004 Part No 10014299 ...
Страница 4: ...VPN 615 RELIABILITY 665 QOS 681 DIAL UP 721 ...
Страница 6: ...2 ABOUT THIS GUIDE ...
Страница 7: ...I GETTING STARTED Chapter 1 3Com Router Introduction Chapter 2 3Com Router User Interface ...
Страница 8: ...4 ...
Страница 16: ...12 CHAPTER 1 3COM ROUTER INTRODUCTION ...
Страница 34: ...30 ...
Страница 60: ...56 CHAPTER 3 SYSTEM MANAGEMENT ...
Страница 88: ...84 CHAPTER 5 CONFIGURING NETWORK MANAGEMENT RouterA interface ethernet 0 RouterA Ethernet0 rmon promiscuous ...
Страница 98: ...94 CHAPTER 6 DISPLAY AND DEBUGGING TOOLS ...
Страница 110: ...106 ...
Страница 114: ...110 CHAPTER 8 INTERFACE CONFIGURATION OVERVIEW ...
Страница 158: ...154 CHAPTER 10 CONFIGURING WAN INTERFACE ...
Страница 168: ...164 ...
Страница 188: ...184 CHAPTER 13 CONFIGURING PPPOE CLIENT ...
Страница 192: ...188 CHAPTER 14 CONFIGURING SLIP Router ip route static 0 0 0 0 0 0 0 0 10 110 0 1 ...
Страница 248: ...244 CHAPTER 16 CONFIGURING LAPB AND X 25 ...
Страница 292: ...288 CHAPTER 18 CONFIGURING HDLC Enable HDLC packet debugging debugging hdlc packet interface type number ...
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Страница 330: ...326 CHAPTER 20 CONFIGURING IP ADDRESS ...
Страница 362: ...358 CHAPTER 21 CONFIGURING IP APPLICATION ...
Страница 374: ...370 CHAPTER 23 CONFIGURING IP COUNT ...
Страница 406: ...402 CHAPTER 25 CONFIGURING DLSW ...
Страница 408: ...404 ...
Страница 452: ...448 CHAPTER 29 CONFIGURING OSPF ...
Страница 482: ...478 CHAPTER 30 CONFIGURING BGP ...
Страница 494: ...490 CHAPTER 31 CONFIGURING IP ROUTING POLICY ...
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Страница 508: ...504 CHAPTER 33 IP MULTICAST ...
Страница 514: ...510 CHAPTER 34 CONFIGURING IGMP ...
Страница 526: ...522 CHAPTER 36 CONFIGURING PIM SM ...
Страница 528: ...524 ...
Страница 532: ...528 CHAPTER 37 CONFIGURING TERMINAL ACCESS SECURITY ...
Страница 550: ...546 CHAPTER 38 CONFIGURING AAA AND RADIUS PROTOCOL ...
Страница 590: ...586 CHAPTER 40 CONFIGURING IPSEC ...
Страница 599: ...IX VPN Chapter 42 Configuring VPN Chapter 43 Configuring L2TP Chapter 44 Configuring GRE ...
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Страница 638: ...634 CHAPTER 43 CONFIGURING L2TP ...
Страница 649: ...X RELIABILITY Chapter 45 Configuring a Standby Center Chapter 46 Configuring VRRP ...
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Страница 670: ...666 CHAPTER 47 QOS OVERVIEW ...
Страница 700: ...696 CHAPTER 49 CONGESTION MANAGEMENT ...
Страница 706: ...702 CHAPTER 50 CONGESTION AVOIDANCE ...
Страница 707: ...XII DIAL UP Chapter 51 Configuring DCC Chapter 52 Configuring Modem ...
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