Configuring Custom Lines

Scenarios

Public DNS resolution provides you with more than 300 carrier and region lines. You can also configure custom resolution lines based on specific IP address ranges. Usually, a DNS server returns the same IP address to all visitors, irrespective of where they come from. With custom lines, the DNS server returns a specific IP address based on the IP addresses of visitors.

• If the local DNS server of the broadband service provider used by the visitor does not support the Extension Mechanisms for DNS (EDNS), the authoritative DNS server checks whether the public IP address of the local DNS server matches the configured IP address range of the custom line.
• If the local DNS server of the broadband service provider used by the visitor supports EDNS, the authoritative DNS server checks whether the visitor's public IP address encapsulated in the EDNS matches the configured IP address range of the custom line.
• If IP address scheduling through ISP lines or region lines is inaccurate, you can configure custom lines to address this issue.

You can configure custom resolution lines to obtain different resolution results based on source IP addresses of visitors.

If your website (example.com) is providing services both for external and internal users, you can configure different resolution lines so that the DNS server can return the external server address (1.1.1.1) to external users and internal server address (2.2.2.2) to internal users.

Add Custom Resolution Lines

1. Go to the Custom Lines page.
2. Click Add Custom Line.
3. Configure the parameters based on Table 1.

   Table 1 Parameters for adding a custom resolution line

   Parameter	Description	Value 1	Value 2
   Line Name	Custom line name	Line 1	Line 2
   IP Address Range	Source IP address range Enter a range of 1 to 50 IP addresses and separate the start and end IP addresses with a hyphen (-).	1.0.0.1-1.0.0.2	1.0.0.3-1.0.0.4

4. Click OK.

Add Record Sets with Custom Lines

For example, add record sets for example.com with Line 1 (to IP address 1.1.1.1) and Line 2 (to IP address 2.2.2.2).

1. Go to the Public Zones page.
2. On the Public Zones page, click the domain name (example.com) of the public zone.
3. Click Add Record Set.

   The Add Record Set dialog box is displayed.

4. Add two A record sets for example.com. Configure the parameters based on Table 2.

   Table 2 Parameters for adding an A record set

   Parameter	Description	Line 1	Line 2
   Type	Record set type. Select a record set type based on service requirements. For details, see Table 1. An A record set is selected here.	A – Map domains to IPv4 addresses	A – Map domains to IPv4 addresses
   Name	Prefix of the domain name to be resolved. This value is left empty by default. For example, if the domain name is example.com, the value of the Name can be as follows: www: The domain name is www.example.com and usually used for a website. Left blank: The domain name is example.com and usually used for a website. To use an at sign (@) as the domain name prefix, just leave this parameter blank. abc: The domain name is abc.example.com, a subdomain of example.com. mail: The domain name is mail.example.com and usually used for email servers. *: The domain name is *.example.com. It covers all subdomains of example.com.	www	www
   Line	Resolution line. The DNS server will return the IP address of the specified line, depending on where end users come from. The default value is Default. Default: returns the default resolution result irrespective of where the visitors come from. ISP: returns the resolution result based on end users' carrier networks. For details, see Configuring ISP Lines. Region: returns the resolution result based on end users' geographical locations. For details, see Configuring Region Lines. Custom Lines: returns the resolution result based on specified IP address ranges. For details, see Configuring Custom Lines. Select Custom Lines for Line and select the desired line name.	Resolution Lines_Line1	Resolution Lines_Line2
   TTL (s)	How long a local DNS server caches a DNS record. It is measured in seconds. Default value: 300 Value range: 1 to 2147483647 If your service address changes frequently, set TTL to a smaller value. Otherwise, set TTL to a larger value.	Default value: 300	Default value: 300
   Value	Returned result of domain name resolution. For details, see Table 1.	1.1.1.1	2.2.2.2
   Alias	Whether to associate the record set with a cloud resource. Unlike a CNAME record set, an alias supports second-level domain names. This option is disabled by default. Types of record sets that support alias include A, MX, AAAA, TXT, SRV and CAA.	No	No
   Tag	Identifier of the record set. Each tag contains a key and a value. You can add up to 20 tags for a record set. The tag key: Cannot be left blank. Must be unique for each resource. Can contain a maximum of 128 characters. Cannot start or end with a space, or cannot start with _sys_. Only letters, digits, spaces, and the following special characters are allowed: _.:=+-@ The tag value: Can be left blank. Can contain a maximum of 255 characters. Can contain letters, digits, spaces, and special characters _ . : / = + - @. NOTE: If your organization has configured tag policies for the DNS service, you need to add tags to your record sets based on the tag policies. If you add a tag that does not comply with the tag policies, record sets may fail to be created. Contact the administrator to learn more about tag policies.	example_key1 example_value1	example_key1 example_value1
   Description	Supplementary information about the record set. Can contain a maximum of 255 characters.	-	-

5. Click OK.