1. whois
a. [Domain Name] DOCOMO.NE.JP d. [Network Service Name] i mode service l. [Organization Type] Network Service m. [Administrative Contact] JN9094JP n. [Technical Contact] JN9094JP p. [Name Server] ns001.docomo.ne.jp p. [Name Server] ns002.docomo.ne.jp s. [Signing Key] [State] Connected (2023/07/31) [Registered Date] 1998/07/17 [Connected Date] 1998/07/30 [Last Update] 2022/08/01 01:02:16 (JST) ns002.docomo.ne.jp. 86400 IN A 49.102.160.24 ns001.docomo.ne.jp. 86400 IN A 49.102.160.23 docomo.ne.jp. 3204 IN TXT "v=spf1 +ip4:203.138.203.0/24 +ip4:210.153.87.192/29 +ip4:210.153.87.224/29 ~all"
1.203.138.203.in-addr.arpa. 3600 IN PTR mail101.docomo.ne.jp.
203.138.203.16
2. history
$ dig -x 210.153.87.192 210.153.87.224