1.3 Asking Questions You Can t Find Answers To

1.3 Asking Questions You Can't Find Answers To

1.3.1 Problem

You have a pressing question about DNS or BIND and can't find the answer in this book.

1.3.2 Solution

Check one of the relevant mailing lists or newsgroups:

The BIND Users mailing list, at bind-users@isc.org , discusses the operation and configuration of BIND name servers and resolvers . BIND Users is bidirectionally gatewayed to the Usenet newsgroup comp.protocols.dns.bind .
The BIND 9 Users mailing list, at bind9-users@isc.org, discusses the operation and configuration of BIND 9 name servers.

You can also try asking me at Cricket's Corner: http://www.menandmice.com/9000/9300_DNS_Corner.html. I can't answer every question, but I answer as many as I can.

1.3.3 Discussion

Before asking a question on either of these mailing lists or the newsgroup, be sure to check their archives. See Section 1.2 for their locations. If everyone did this, the volume of messages on the mailing lists would drop precipitously, and newbies would get fewer curt or exasperated answers from cranky old-timers like me. (And we'd all live happily ever after.)

You may want to subscribe to one of the mailing lists or the newsgroup above, rather than just posing your question, getting an answer and disappearing until the next question pops into your head. Subscribing guarantees that you'll see any replies (since some folks won't copy you on responses) and will expose you to a wealth of DNS and BIND knowledge.

To subscribe to BIND Users or BIND 9 Users, send a message with the word "subscribe" in the body to bind-users-request@isc.org or bind9-users-request@isc.org, as appropriate.

1.3.4 See Also

Section 1.2 and "Handy Mailing Lists and Usenet Newsgroups" in Chapter 3 of DNS and BIND .

1.4 Getting a List of Top-Level Domains

1.4.1 Problem

You need a list of top-level domains (TLDs), possibly to figure out which one your organization belongs in.

1.4.2 Solution

See http://www.norid.no/domreg.html for an alphabetical list of top-level domains. See http://www.norid.no/domreg-alpha.html for a list of top-level domains alphabetized by country name (instead of the top-level domain label). Each list includes links to the registration authority for each TLD.

1.4.3 Discussion

The most recent edition of DNS and BIND, as of this writing, also contains a list of top-level domains as its Appendix A. However, that list does not include the new generic top-level domains (e.g., biz and info ), as they were introduced after that edition's publication.

1.4.4 See Also

Appendix A of DNS and BIND .

1.5 Checking Whether a Domain Name Is Registered

1.5.1 Problem

You want to check whether a particular domain name is already registered, or who has registered that domain name.

1.5.2 Solution

Use the whois service offered by the appropriate registration authority, or use a command-line version of whois to look up registration information about the domain name you're interested in.

The Internet Assigned Numbers Authority, or IANA, maintains a list of country-code top-level domains (ccTLDs) at http://www.iana.org/cctld/cctld-whois.htm,which includes links to the web pages of those ccTLDs registration authorities. Many of these web pages offer online whois lookups. The web site http://www.allwhois.com/also includes links to many whois lookup facilities.

If your host's operating system includes a command-line whois client, you can use that to look up to look up registration information about the domain name. Newer whois clients automatically determine which whois server to query, so you can simply run:

$ whois


domain-name

Older whois clients may require you to specify the whois server to use. For these, you can try tld.whois-server.net . For example:

$ whois -h ca.whois-servers.net risq.ca

The whois output usually contains information about the registrant (the person or organization that registered the domain name). For example:

$ whois isc.org

produces output that includes:

Registrant:
Internet Software Consortium (ISC2-DOM)
   950 Charter Street
   Redwood City, CA 94062
   US

   Domain Name: ISC.ORG

   Administrative Contact, Billing Contact:
      Conrad, David Randolph  (DC396)  drc@ISC.ORG
      Internet Software Consortium
      950 Charter Street
      Redwood City, CA 94063
      1-650-779-7061 (FAX) 1-650-779-7055
   Technical Contact:
      Vixie, Paul  (PV15)  paul@VIX.COM
      M.I.B.H., LLC
      950 Charter Street
      Redwood City, CA 94063
      +1.650.779.7000 (FAX) +1.650.779.7055

   Record last updated on 04-Mar-2002.
   Record expires on 05-Apr-2004.
   Record created on 04-Apr-1994.
   Database last updated on 14-Mar-2002 09:39:00 EST.

   Domain servers in listed order:

   NS-EXT.VIX.COM               204.152.184.64
   NS1.GNAC.COM                 209.182.195.77

1.5.3 Discussion

If the registration authority for your prospective top-level domain doesn't offer a whois server, or you can't find it, you can look up NS records for the domain name you're interested in. For example:

$ dig ns


domain-name

If the domain name has NS records, it's very likely registered. On the other hand, if a domain name lacks NS records, it may still be registered: some TLDs take a day or more to process a new registration and add the corresponding NS records.