21.3.2. Reverse Settings of Global IP Address Used without Enterprise Cloud 2.0

With the reverse DNS lookup function, this section
explains how to made the reverse lookup settings with the global IP address that is used without Enterprise Cloud 2.0.

This section includes many descriptions about issues not supported (e.g., general setting-related issues of DNS). Customers are certainly expected to back up pre-edit settings on their own and well comprehend the setting items. Regarding transfer of authority for IP address reverse lookup, the application method and setting method differ depending on IP address providers used by customers. Contact the used provider directly.

21.3.2.1. [Example] Reverse lookup settings

With the items given below, the example here shows how to make the reverse lookup settings.

  • IP address to be found by the reverse lookup.

    198.51.100.200

  • Host name to be found by the reverse lookup.

    example.com.

21.3.2.2. Step 1. Adding a host zone

Register a host zone needed for reverse lookup. As a prerequisite, “owner” needs to be written in the PTR record, as defined by RFC1035. To write “owner”, domain “in-addr.arpa.” defined by RFC2317 is to be used. This is a domain for DNS reverse lookup for IPv4, and “200.100.51.198.in-addr.arpa.” is solved for reverse lookup of IP address “198.51.100.200”. That is, if solution of PTR record “200.100.51.198.in-addr.arpa.” results in “example.com.”, reverse lookup is possible. First, to enable registration of this record, register host zone “200.100.51.198.in-addr.arpa.” in DNS of this service.

Note

Reference: Creating Zone

Jot down the NS record issued at this time. In this example, the following NS record is assumed. - ns-01.dns.jp-e1.cloudn-service.com - ns-02.dns.jp-e1.cloudn-service.com - ns-03.dns.jp-e1.cloudn-service.com

21.3.2.3. Step 2. Adding a recordset

Next, create recordset “200.100.51.198.in-addr.arpa.” under host zone “100.51.198.in-adde.arpa.” just created. In this example, the following are assumed. - Name: 200 - Type: PTR-Pointer - Value: example.com. * A dot (.) after ezample.com also needs to be entered. * An absolute domain name starting from the root needs to be written.

Note

Reference: Creating Recordset

21.3.2.4. Step 3. Verifying the record

Check if registration has been properly performed on the DNS of this service. Check the record on the DNS with the following command.

$ dig @dns101-1.jp1.ecl.ntt.com -x 198.51.100.200

When the response below is returned, it means that registration of this service as the DNS is completed.

; <<>> DiG 9.8.3-P1 <<>> @dns103-1.jp1.ecl.ntt.com -x 111.68.200.113
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 50838
;; flags: qr aa rd; QUERY: 1, ANSWER: 1, AUTHORITY: 3, ADDITIONAL: 0
;; WARNING: recursion requested but not available

;; QUESTION SECTION:
;200.100.51.198.in-addr.arpa. IN PTR

;; ANSWER SECTION:
200.100.51.198.in-addr.arpa. 60 IN PTR example.com

;; AUTHORITY SECTION:
100.51.198.in-addr.arpa. 60 IN NS dns101-1.jp1.ecl.ntt.com.
100.51.198.in-addr.arpa. 60 IN NS dns101-2.uk1.ecl.ntt.com.
100.51.198.in-addr.arpa. 60 IN NS dns101-3.us1.ecl.ntt.com.
100.51.198.in-addr.arpa. 60 IN NS dns101-4.sg1.ecl.ntt.com.

;; Query time: 70 msec
;; SERVER: 153.128.36.49#53(153.128.36.49)
;; WHEN: Wed Nov 16 13:48:48 2016
;; MSG SIZE rcvd: 156

Next, check with the command below that the reverse lookup settings have been completed. * command Now the settings are completed.

$ dig -x 198.51.100.200

Setting up is completed.

Note

“When the expected response is not returned, check the following.
-Check if cache resulted from execution of dig with the same IP address remains.
-Check if the setting of reverse lookup DNS has been completed by the registration company being used. From domain registration to DNS record”