CLI: Example for Configuring ISP Link Selection to Forward Traffic by ISPs

This section provides an example for configuring ISP link selection to forward traffic by ISPs.

Networking Requirements

As shown in Figure 1, the FW is deployed at the network egress as the security gateway. The enterprise has two links connected separately to ISP1 and ISP2.

The enterprise requires that packets to Server 1 be forwarded on ISP1 link and packets to Server 2 be forwarded on ISP2 link.
When one link is faulty, follow-up traffic will be forwarded on the other link to ensure transmission availability.

Figure 1 Networking diagram for configuring ISP link selection

Configuration Roadmap

Configure the health check function. Configure health check tasks for ISP1 and ISP2.
Set interface IP addresses, security zones, and gateway addresses. Apply health check on the interfaces.
Make two ISP address files, isp1.csv and isp2.csv, write Server 1 IP address 3.3.3.3 into isp1.csv and Server 2 IP address 9.9.9.9 into isp2.csv, and upload the two ISP address files to the FW.
Configure ISP link selection to forward packets destined for Server 1 from ISP1 link and packets destined for Server 2 link from ISP2 link.
Configure a basic security policy to allow intranet users to access the Internet.

This example focuses on the configuration related to ISP link selection. Configure other data such as NAT based on the actual networking.

Procedure

Enable the health check function and create a health check for ISP1 and ISP2 link respectively.

<FW> system-view
[FW] healthcheck enable
[FW] healthcheck name isp1_health
[FW-healthcheck-isp1_health] destination 3.3.10.10 interface GigabitEthernet 0/0/1 protocol tcp-simple destination-port 10001
[FW-healthcheck-isp1_health] destination 3.3.10.11 interface GigabitEthernet 0/0/1 protocol tcp-simple destination-port 10002
[FW-healthcheck-isp1_health] quit
[FW] healthcheck name isp2_health
[FW-healthcheck-isp2_health] destination 9.9.20.20 interface GigabitEthernet 0/0/7 protocol tcp-simple destination-port 10003
[FW-healthcheck-isp2_health] destination 9.9.20.21 interface GigabitEthernet 0/0/7 protocol tcp-simple destination-port 10004
[FW-healthcheck-isp2_health] quit

Assume that 3.3.10.10 and 3.3.10.11 are known device addresses on the ISP1 network and that 9.9.20.20 and 9.9.20.21 are known device addresses on the ISP2 network.

If the state remains down after the health check configuration is complete, check the health check configuration.

Configuring IP addresses and gateway addresses for interfaces and apply health check to the interfaces.

[FW] interface GigabitEthernet 0/0/1
[FW-GigabitEthernet0/0/1] ip address 1.1.1.1 255.255.255.0
[FW-GigabitEthernet0/0/1] gateway 1.1.1.254
[FW-GigabitEthernet0/0/1] healthcheck isp1_health
[FW-GigabitEthernet0/0/1] quit
[FW] interface GigabitEthernet 0/0/3
[FW-GigabitEthernet0/0/3] ip address 10.3.0.1 255.255.255.0
[FW-GigabitEthernet0/0/3] quit
[FW] interface GigabitEthernet 0/0/7
[FW-GigabitEthernet0/0/7] ip address 2.2.2.2 255.255.255.0
[FW-GigabitEthernet0/0/7] gateway 2.2.2.254
[FW-GigabitEthernet0/0/7] healthcheck isp2_health
[FW-GigabitEthernet0/0/7] quit

Upload ISP address files to the FW using SFTP. The imported ISP address files are stored in the isp folder in the root directory.Details are omitted.
Create ISP name isp1_ifgrp for ISP1 and ISP name isp2_ifgrp for ISP2 and associate them with the corresponding ISP address files.
```
[FW] isp name isp1_ifgrp set filename isp1.csv
[FW] isp name isp2_ifgrp set filename isp2.csv
```

Create an ISP interface group for ISP1 and ISP2 respectively and add interfaces to corresponding ISP interface groups. Then ISP routes will be delivered by default.

[FW] interface-group 1 isp isp1_ifgrp
[FW-interface-isp-group-1] add interface GigabitEthernet 0/0/1
[FW-interface-isp-group-1] quit
[FW] interface-group 2 isp isp2_ifgrp
[FW-interface-isp-group-2] add interface GigabitEthernet 0/0/7
[FW-interface-isp-group-2] quit

Assign the interfaces to security zones.

[FW] firewall zone trust
[FW-zone-trust] add interface GigabitEthernet 0/0/3
[FW-zone-trust] quit
[FW] firewall zone untrust
[FW-zone-untrust] add interface GigabitEthernet 0/0/1
[FW-zone-untrust] add interface GigabitEthernet 0/0/7
[FW-zone-untrust] quit

Configure a Trust-to-Untrust interzone security policy to allow enterprise network users to access Internet resources. Assume that enterprise network users reside on 10.3.0.0/24.

[FW-policy-security] rule name policy_sec_trust_untrust
[FW-policy-security-rule-policy_sec_trust_untrust] source-zone trust
[FW-policy-security-rule-policy_sec_trust_untrust] destination-zone untrust
[FW-policy-security-rule-policy_sec_trust_untrust] source-address 10.3.0.0 24
[FW-policy-security-rule-policy_sec_trust_untrust] action permit
[FW-policy-security-rule-policy_sec_trust_untrust] quit
[FW-policy-security] quit

Configuration Scripts

#
 isp name isp1_ifgrp set filename isp1.csv
 isp name isp2_ifgrp set filename isp2.csv
#
healthcheck enable
healthcheck name isp1_health
 destination 3.3.10.10 interface GigabitEthernet0/0/1 protocol tcp-simple destination-port 10001
 destination 3.3.10.11 interface GigabitEthernet0/0/1 protocol tcp-simple destination-port 10002
healthcheck name isp2_health
 destination 9.9.20.20 interface GigabitEthernet0/0/7 protocol tcp-simple destination-port 10003
 destination 9.9.20.21 interface GigabitEthernet0/0/7 protocol tcp-simple destination-port 10004
#
interface GigabitEthernet0/0/1
 ip address 1.1.1.1 255.255.255.0
 healthcheck isp1_health
 gateway 1.1.1.254
#
interface GigabitEthernet0/0/3
 ip address 10.3.0.1 255.255.255.0
#
interface GigabitEthernet0/0/7
 ip address 2.2.2.2 255.255.255.0
 healthcheck isp2_health
 gateway 2.2.2.254
#
firewall zone trust
  set priority 85
  add interface GigabitEthernet0/0/3
#
firewall zone untrust
 set priority 5
 add interface GigabitEthernet0/0/1
 add interface GigabitEthernet0/0/7
#
security-policy
 rule name policy_sec_trust_untrust
  source-zone trust
  destination-zone untrust
  source-address 10.3.0.0 mask 255.255.255.0
  action permit
#
interface-group 1 isp isp1_ifgrp
 add interface GigabitEthernet0/0/1
#
interface-group 2 isp isp2_ifgrp
 add interface GigabitEthernet0/0/7
#
return