AR系列路由器包过滤控制访问列表的配置方法
对内网地址192.168.1.0/25访问外网不作限制
对于内网地址192.168.1.128/25只允许收发邮件，不允许访问外网
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sysname RouterA
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firewall enable /使能防火墙功能/
firewall default deny /配置防火墙缺省操作为deny/
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radius scheme system
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domain system
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acl number 2000 /定义用于NAT转换的ACL/
rule 0 permit source 192.168.1.0 0.0.0.255
rule 1 deny
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acl number 3001 /定义用于包过滤的ACL/
rule 0 permit ip source 192.168.1.0 0.0.0.127
/内网地址192.168.1.0/25访问外网不作限制/
rule 1 permit tcp source 192.168.1.128 0.0.0.127 destination-port eq pop3
rule 2 permit tcp source 192.168.1.128 0.0.0.127 destination-port eq smtp
/内网地址192.168.1.128/25只能收发邮件/
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interface Ethernet1/0/0
ip address 192.168.1.1 255.255.255.0
firewall packet-filter 3001 inbound /对inbound流量使用包过滤/
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interface Serial2/0/0
link-protocol ppp
ip address 202.101.1.2 255.255.255.252
nat outbound 2000
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interface NULL0
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ip route-static 0.0.0.0 0.0.0.0 202.101.1.1 preference 60
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user-interface con 0
user-interface vty 0 4
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return
通过查看disp firewall-statistics all、disp acl 3001确认防火墙确实生效
disp firewall-statistics all
Firewall is enable, default filtering method is 'deny'.
Interface: Ethernet1/0/0
In-bound Policy: acl 3001
Fragments matched normally
From 2006-05-31 5:05:50 to 2006-05-31 6:32:49
198 packets, 24129 bytes, 4% permitted,
0 packets, 0 bytes, 0% denied,
0 packets, 0 bytes, 0% permitted default,
5919 packets, 1021492 bytes, 96% denied default,
Totally 198 packets, 24129 bytes, 4% permitted,
Totally 5919 packets, 1021492 bytes, 96% denied.
disp acl 3001
Advanced ACL 3001, 3 rules
Acl's step is 1
rule 0 permit ip source 192.168.1.0 0.0.0.127 (194 times matched)
rule 1 permit tcp source 192.168.1.128 0.0.0.127 destination-port eq pop3 (9 times matched)
rule 2 permit tcp source 192.168.1.128 0.0.0.127 destination-port eq smtp (0 times matched)
【提示】
1、 系统缺省情况下为禁止防火墙（firewall disable），需要使用命令“firewall enable”来使能防火墙功能
2、 防火墙缺省过滤方式为允许通过（permit），可以通过“firewall default deny”修改为禁止通过
3、 在内网使用包过滤，并同时使用DHCP server分配地址时，需要在acl 3001中添加一条“rule 0 permit ip source 0.0.0.0 0”否则会出现DHCP Server无法分配地址的问题。