某公司三层交换机与USG6650防火墙对接外网上网配置案例
配置需求
某公司拥有多个部门且位于不同网段，各部门均有访问外网的需求。公司内部设备需要通过三层交换机和USG6650防火墙访问外部网络，且要求三层交换机作为公司网关。
如图
配置思路
采用如下思路进行配置：
配置交换机作为用户的网关，通过VLANIF接口，实现跨网段用户互访。
配置交换机作为DHCP服务器，为用户分配IP地址。
开启防火墙域间安全策略，使不同域的报文可以相互转发。
配置防火墙PAT转换功能，使用户可以访问外部网络。
操作步骤
配置交换机
# 配置连接用户的接口和对应的VLANIF接口。
<HUAWEI> system-view
[HUAWEI] sysname Switch
[Switch] vlan batch 2 3
[Switch] interface gigabitethernet 0/0/2
[Switch-GigabitEthernet0/0/2] port link-type access //配置接口接入类型为access
[Switch-GigabitEthernet0/0/2] port default vlan 2 //配置接口加入VLAN 2
[Switch-GigabitEthernet0/0/2] quit
[Switch] interface gigabitethernet 0/0/3
[Switch-GigabitEthernet0/0/3] port link-type access
[Switch-GigabitEthernet0/0/3] port default vlan 3
[Switch-GigabitEthernet0/0/3] quit
[Switch] interface vlanif 2
[Switch-Vlanif2] ip address 192.168.1.1 24
[Switch-Vlanif2] quit
[Switch] interface vlanif 3
[Switch-Vlanif3] ip address 192.168.2.1 24
[Switch-Vlanif3] quit
# 配置连接防火墙的接口和对应的VLANIF接口。
[Switch] vlan batch 100
[Switch] interface gigabitethernet 0/0/1
[Switch-GigabitEthernet0/0/1] port link-type access
[Switch-GigabitEthernet0/0/1] port default vlan 100
[Switch-GigabitEthernet0/0/1] quit
[Switch] interface vlanif 100
[Switch-Vlanif100] ip address 192.168.100.2 24
[Switch-Vlanif100] quit
# 配置缺省路由。
[Switch] ip route-static 0.0.0.0 0.0.0.0 192.168.100.1 //缺省路由的下一跳是防火墙接口的IP地址192.168.100.1
# 配置DHCP服务器。
[Switch] dhcp enable
[Switch] interface vlanif 2
[Switch-Vlanif2] dhcp select interface //DHCP使用接口地址池的方式为用户分配IP地址
[Switch-Vlanif2] dhcp server dns-list 114.114.114.114 223.5.5.5 //配置的DNS-List 114.114.114.114是公用的DNS服务器地址，是不区分运营商的。在实际应用中，请根据运营商分配的DNS进行配置
[Switch-Vlanif2] quit
[Switch] interface vlanif 3
[Switch-Vlanif3] dhcp select interface
[Switch-Vlanif3] dhcp server dns-list 114.114.114.114 223.5.5.5
[Switch-Vlanif3] quit
配置防火墙
# 配置连接交换机的接口对应的IP地址。
<USG6600> system-view
[USG6600] interface gigabitethernet 1/0/1
[USG6600-GigabitEthernet1/0/1] ip address 192.168.100.1 255.255.255.0
[USG6600-GigabitEthernet1/0/1] quit
# 配置连接公网的接口对应的IP地址。
[USG6600] interface gigabitethernet 1/0/2
[USG6600-GigabitEthernet1/0/2] ip address 203.0.113.2 255.255.255.0 //配置连接公网接口的IP地址和公网的IP地址在同一网段
[USG6600-GigabitEthernet1/0/2] quit
# 配置缺省路由和回程路由。
[USG6600] ip route-static 0.0.0.0 0.0.0.0 203.0.113.1 //配置静态缺省路由的下一跳指向公网提供的IP地址203.0.113.1
[USG6600] ip route-static 192.168.0.0 255.255.0.0 192.168.100.2 //配置回程路由的下一跳就指向交换机上行接口的IP地址192.168.100.2
# 配置安全策略。
[USG6600] firewall zone trust //配置trust域
[USG6600-zone-trust] add interface gigabitethernet 1/0/1
[USG6600-zone-trust] quit
[USG6600] firewall zone untrust //配置untrust域
[USG6600-zone-untrust] add interface gigabitethernet 1/0/2
[USG6600-zone-untrust] quit
# 配置安全策略，允许域间互访。
[USG6600] security-policy
[USG6600-policy-security] rule name policy1
[USG6600-policy-security-rule-policy1] source-zone trust
[USG6600-policy-security-rule-policy1] destination-zone untrust
[USG6600-policy-security-rule-policy1] source-address 192.168.0.0 mask 255.255.0.0
[USG6600-policy-security-rule-policy1] action permit
[USG6600-policy-security-rule-policy1] quit
[USG6600-policy-security] quit
# 配置PAT地址池，开启允许端口地址转换。
[USG6600] nat address-group addressgroup1
[USG6600-address-group-addressgroup1] mode pat
[USG6600-address-group-addressgroup1] route enable
[USG6600-address-group-addressgroup1] section 0 203.0.113.2 203.0.113.2 //转换的公网IP地址
[USG6600-address-group-addressgroup1] quit
# 配置源PAT策略，实现私网指定网段访问公网时自动进行源地址转换。
[USG6600] nat-policy
[USG6600-policy-nat] rule name policy_nat1
[USG6600-policy-nat-rule-policy_nat1] source-zone trust
[USG6600-policy-nat-rule-policy_nat1] destination-zone untrust
[USG6600-policy-nat-rule-policy_nat1] source-address 192.168.0.0 mask 255.255.0.0 //允许进行PAT转换的源IP地址
[USG6600-policy-nat-rule-policy_nat1] action source-nat address-group addressgroup1
[USG6600-policy-nat-rule-policy_nat1] quit
[USG6600-policy-nat] quit
[USG6600] quit
检查配置结果
配置PC1的IP地址为192.168.1.2/24，网关为192.168.1.1；PC2的IP地址为192.168.2.2/24，网关为192.168.2.1。
配置外网PC的IP地址为203.0.113.1/24，网关为203.0.113.2。
配置完成后，PC1和PC2都可以Ping通外网的IP 203.0.113.1/24，PC1和PC2都可以访问Internet。
配置文件
Switch的配置文件
#
sysname Switch
#
vlan batch 2 to 3 100
#
dhcp enable
#
interface Vlanif2
ip address 192.168.1.1 255.255.255.0
dhcp select interface
dhcp server dns-list 114.114.114.114 223.5.5.5
#
interface Vlanif3
ip address 192.168.2.1 255.255.255.0
dhcp select interface
dhcp server dns-list 114.114.114.114 223.5.5.5
#
interface Vlanif100
ip address 192.168.100.2 255.255.255.0
#
interface GigabitEthernet0/0/1
port link-type access
port default vlan 100
#
interface GigabitEthernet0/0/2
port link-type access
port default vlan 2
#
interface GigabitEthernet0/0/3
port link-type access
port default vlan 3
#
ip route-static 0.0.0.0 0.0.0.0 192.168.100.1
#
return
USG的配置文件
#
interface GigabitEthernet1/0/1
ip address 192.168.100.1 255.255.255.0
#
interface GigabitEthernet0/0/2
ip address 203.0.113.2 255.255.255.0
#
firewall zone trust
set priority 85
add interface GigabitEthernet1/0/1
#
firewall zone untrust
set priority 5
add interface GigabitEthernet0/0/2
#
ip route-static 0.0.0.0 0.0.0.0 203.0.113.1
ip route-static 192.168.0.0 255.255.0.0 192.168.100.2
#
nat address-group addressgroup1 0
mode pat
route enable
section 0 203.0.113.2 203.0.113.2
#
security-policy
rule name policy1
source-zone trust
destination-zone untrust
source-address 192.168.0.0 mask 255.255.0.0
action permit
#
nat-policy
rule name policy_nat1
source-zone trust
destination-zone untrust
source-address 192.168.0.0 mask 255.255.0.0
action source-nat address-group addressgroup1
#
return
