sshd[1234]: reverse mapping checking getaddrinfo for failed - POSSIBLE BREAKIN ATTEMPT!

daily memorandum 2.3.0(2006-01-26) より

   sshd[1402]: Invalid user negro from 72.20.1.178

って感じなので、多分この 72.20.1.178 からアクセスしてるのだろうと思って、とりあえず逆引きしてみると・・・

1999,red,p1,0$ nslookup -q=any 178.1.20.72.in-addr.arpa
Server:         192.168.1.254
Address:        192.168.1.254#53

Non-authoritative answer:
178.1.20.72.in-addr.arpa        name = .

Authoritative answers can be found from:

おおっっ、逆引き名が「.」どう設定するとこうなるんだ．へぇー．

2000,red,p1,0$ nslookup -q=any 1.20.72.in-addr.arpa
Server:         192.168.1.254
Address:        192.168.1.254#53

Non-authoritative answer:
1.20.72.in-addr.arpa    nameserver = ns4.staminus.net.
1.20.72.in-addr.arpa    nameserver = ns5.staminus.net.
1.20.72.in-addr.arpa    nameserver = ns6.staminus.net.
1.20.72.in-addr.arpa    nameserver = ns1.staminus.net.
1.20.72.in-addr.arpa    nameserver = ns2.staminus.net.
1.20.72.in-addr.arpa    nameserver = ns3.staminus.net.

Authoritative answers can be found from:

2001,red,p1,0$ whois staminus.net

Whois Server Version 1.3

   Domain Name: STAMINUS.NET
   Registrar: DOTSTER, INC.
   Whois Server: whois.dotster.com
   Referral URL: http://www.dotster.com
   Name Server: NS1.STAMINUS.NET
   Name Server: NS2.STAMINUS.NET
   Name Server: NS4.STAMINUS.NET
   Name Server: NS5.STAMINUS.NET
   Name Server: NS6.STAMINUS.NET
   Name Server: NS3B.STAMINUS.NET
   Status: REGISTRAR-LOCK
   Updated Date: 30-nov-2005
   Creation Date: 25-jul-2001
   Expiration Date: 25-jul-2006

Registrant:
   Staminus Communications
   502 S. Harbor Blvd.
   Fullerton, CA 92832
   US

   Registrar: DOTSTER
   Domain Name: STAMINUS.NET
      Created on: 25-JUL-01
      Expires on: 25-JUL-06
      Last Updated on: 30-NOV-05

   Administrative Contact:
      Mahvi, Matt  toro00@yahoo.com
      502 S. Harbor Blvd
      Fullerton, CA  92382
      US
      949-551-3385

   Technical Contact:
      Mahvi, Mehdi  support@staminus.net
      Staminus Communications
      502 S. Harbor Blvd.
      Fullerton, CA  92832
      US
      949-551-3385


   Domain servers in listed order:
      NS1.STAMINUS.NET
      NS2.STAMINUS.NET
      NS3B.STAMINUS.NET
      NS4.STAMINUS.NET
      NS5.STAMINUS.NET
      NS6.STAMINUS.NET

End of Whois Information
2002,red,p1,0$ 

Staminus Communications http://www.staminus.net/ ですって．ホスティングか？