Inbound LLB
System > Network > Basic Network > Load Balancing > Link Load Balancing > Inbound
After enabling LLB for inbound traffic, the system will resolve domains to different IPs based on the sources of DNS requests, and return IPs for different ISPs to the corresponding users who initiate the requests, thus reducing accesses across ISPs. Such a resolution method is known as SmartDNS.
To enable the inbound load balancing function, take the following steps:
- Enable SmartDNS. This is the prerequisite for the implementation of inbound LLB.
- Enable ISP dynamic detection. This function allows system to generate a proximity address based on the proximity route. SmartDNS can reference the proximity address of the specified interface to determine the source of DNS requests.
- Configure a SmartDNS rule table. The smart domain-to-IP resolution is implemented based on the rule table.
Enabling SmartDNS
SmartDNS is enabled by default. To disable or enable the function, click Disable SmartDNS/Enable SmartDNS.
Enabling ISP Dynamic Detection
To enable the ISP dynamic detection, take the following steps:
- Click Interface ISP Dynamic Detection, the Select ISP Dynamic Detection dialog appears.
- Select the interfaces you want to enable the ISP dynamic detection on.
- Click OK.
Configuring a SmartDNS Rule Table
The configuration of SmartDNS rule table includes creating a rule table, specifying the domain name, return IP and matching rule. The system resolves domains names into IPs of different ISP links based on the matching rule.
To create a rule table, take the following steps:
- Click New > Domain, the Domain Configuration dialog appears.
- Enter domain names in the Domain text box. Use comma to seperate multiple domain names. At most 64 domain names are supported in one rule talbe (not case sensitive).
- Click OK to add the domain names.
- In the domain list, select a domian, and then click New > SmartDNS Rule, the New SmartDNS Rule dialog appears. Configure the SmartDNS rule on the dialog. The description of options on the dialog is listed in the table below.
- Click OK.
Notes:
- The priority of proximity address is lower than that of the ISP static address. The system will not match the proximity address unless the matching of ISP static address fails.
- The ISP route being referenced by the SmartDNS rule table cannot be deleted.
- The status of SmartDNS rule table may be active or in active, depending on the status of the interface and the track object.
- 如果只配置了引用的ISP路由但没有配置入站接口，规则状态始终为活跃；
- 如果配置了入站接口但接口上没有配置监测对象，接口的协议状态为可用（UP）时规则状态为活跃，协议状态为不可用（DOWN）时规则状态为非活跃；
- 如果配置了入站接口且接口上配置了监测对象，监测成功时规则状态为活跃，监测失败时规则状态为非活跃。
<新建SmartDNS规则>选项说明：
| 选项 |
说明 |
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域名
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显示已选中的需要被智能解析的域名。
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用户所属ISP
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指定请求源地址需要匹配的ISP名称，从下拉框选择系统中预定义或用户自定义的ISP名称。当请求源地址匹配该ISP中的地址条目，系统返回指定的IP地址。
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返回地址
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对不同请求来源返回不同的IP地址，选项包括：
- IP ：指定返回的IP地址。用户可以为一个域名最多配置64个IP地址。
- 权重 ： 指定返回IP地址的权重。取值范围是1到100，默认值为1。SmartDNS规则表中一个域名可能对应多个IP地址，系统会根据权重值对IP地址进行排序后返回给用户。
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ISP链路
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指定请求源地址需要匹配的接口就近地址簿。当请求源地址匹配该就近地址簿中的地址条目，系统返回指定的IP地址。选项包括：
- 入站接口 - 从下拉框选择请求源地址需要匹配的接口就近地址簿。
- 监测对象 - 从下拉框选择系统中已添加的接口类型监测对象，或新建接口类型监测对象。如果监测对象状态为失败，则该接口上的就近地址簿失效。
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在入站负载均衡页面还可以执行以下操作：
- 点击<SmartDNS规则>列表上方的『编辑』按钮，编辑所选的SmartDNS规则。
- 点击<SmartDNS规则>列表上方的『删除』按钮，删除所选的SmartDNS规则。
- 点击<列选择>下拉菜单，指定<SmartDNS规则>列表中显示的项目。
- 点击『域名』列表中的『编辑』按钮，编辑相应的域名。
- 点击『域名』列表中的『删除』按钮，删除相应的域名。