Geo routing (lines)

Geo routing lets one hostname return different answers to visitors from different places. For example, you can send visitors in Asia to an Asian server, send users of one ISP to a dedicated IP, or send your office network to an internal address. Yeap Cloud DNS calls these conditions 调度线路 (routing lines).

#Kinds of lines

A record's routing line can be built from three kinds of conditions:

You can combine location and ISP, for example "China / Guangdong" plus one ISP. A record with no conditions at all is the hostname's default line. The console shows it as 全局 or 全局默认 (Global default).

How the visitor's location is determined: the nameserver looks at the IP address the query came from to work out location and ISP. If the recursive resolver sends client subnet information (EDNS Client Subnet) with the query, that subnet is used. Otherwise the resolver's own IP is used. So for visitors on a public resolver, the answer depends on whether that resolver sends client subnet information.

#Set a line on a record

1. Open the zone's records page.
2. Add the default record first. Add a record with no line, for example name www, type A, content 203.0.113.10.
3. Add a second record with the same name and type, or edit an existing one. While the row is in edit mode, click its 调度线路 (Routing line) cell to open the 调度线路配置 (Routing line settings) window:
   • 地理位置 (Location): pick continent, country, province/region and city. Each level has an "所有…" (All) option, which means don't narrow further.
   • ISP运营商 (ISP): pick a country and an ISP type, then search for the ISP.
   • 自定义线路 (Custom line): pick a CIDR list.
4. Click 确定 (OK) to close the window, then save the record.

The 调度线路 column in the record list shows each record's line. Hover over it to see the full conditions. The line filter above the list lets you show only 地理定位 (geo-targeted) or 全局默认 (default) records.

#How matching works

For each query, the nameserver looks at the records with the same name and type and picks the set that best matches the visitor:

1. A more precise location wins: city > province/region > country > continent.
2. A record with an ISP set matches only if the visitor's ISP is the same. When it does match, it beats a record at the same location level with no ISP set.
3. A record with a custom line matches only if the visitor's IP is in that CIDR list. A record that has only a custom line (no location and no ISP) ranks at the same level as a continent match when it matches. That is below country-level and more precise location lines.
4. If no record with a line matches, the default record is returned.

For example, say www has three A records: the default 203.0.113.10, "Asia" 198.51.100.20, and "Asia / Japan" 198.51.100.30. A query from Japan gets 198.51.100.30, a query from Singapore gets 198.51.100.20, and a query from Europe gets 203.0.113.10.

#Multiple records and weights

You can have several records with the same name and type on one line, for simple load sharing:

• A / AAAA: all matching records are returned, in a random order each time. The record's 优先级 (Priority) field acts as a weight here. A higher value makes the record more likely to come first. A blank or 0 counts as weight 1. When all records have the same weight, the order is fully random.
• CNAME: only one record is returned each time, picked at random by weight.

#Custom lines (CIDR lists)

#Create a CIDR list

1. Go to DNS管理 → CIDR管理 (DNS Management → CIDR lists). The top of the page shows CIDR配额使用 (CIDR quota used). The quota is the total CIDR allowance across all your DNS plans.
2. Click 添加CIDR (Add CIDR). Enter a CIDR名称 (name) such as "Office egress" and an optional description, then save.
3. In the list, click the list's IP条目数 (entry count, "查看详情" View details) to open its entries page.

#Add IP ranges

• Click 添加条目 (Add entry). Enter the CIDR (for example 192.0.2.0/24 or 2001:db8::/64), an optional description, and the IP版本 (IP version): 自动检测 (auto-detect), IPv4 or IPv6. The version you pick must match the address.

• Or click 批量导入 (Bulk import) and enter one entry per line in this format:

  textCopy

  CIDR|description|IP version
  192.0.2.0/24|Office egress|ipv4
  2001:db8::/64|IPv6 test network

  You can leave out the IP version. It defaults to auto-detect.

• Select several entries and use 批量操作 (Bulk actions) to delete them or change their IP version together.

Lists marked 系统预设 (system preset) come from the platform. You can use them in records, but you can only view them, not edit them.

#Use a list in a record

In 调度线路配置, pick the list under 自定义线路. The 使用状态 (Usage) column on the CIDR lists page shows how many records use each list.