WebDNS: A simple system for distributed-management

WebDNS is a in-house system used to allow support staff to maintain their own host records. This talk will discuss the current system and the future directions that may be taken.

Purpose

• Every host that has an IP address should be registered in the DNS.
• We should know more than just the hostname.

Assumptions

Delegation

• At at the University of Queensland, there are three methods of delegation.
• None - We edit the zone file on the central nameservers.
• Full - A normal DNS delegation to the local nameserver.
• WebDNS - A simple system for distributed management.

Delegation: None

• Pros
  • Simple case - master the zone centrally.
  • Administered by Hostmaster (a role - always there).
  • Central control for any necessary modifications.
• Cons
  • Modifications must go via Hostmaster.
  • As a result, data often out of date, especially for desktops.

Delegation: Full

• Pros
  • Total control is passed to department / whatever.
• Cons
  • No central control short of revoking delegation.
  • Requires local nameserver administration and expertise.
  • Local Hostmaster is not always present.

Delegation: WebDNS

• Pros
  • No local nameserver to administer.
  • Web interface usable from most clients.
  • Less burden of understanding on local support staff.
  • Simple host details management.

Some numbers

• There are 195 delegated subdomains of uq.edu.au, of which
  • 40 are locally edited zone files,
  • 42 are delegated to departmental nameservers, and
  • 113 are generated by WebDNS, containing 10492 host records.

Architecture

Demonstration: webdns.conf

domain  test2.uq.edu.au
subnet  130.102.93      10-29,30-254
users   suter

• The users directive refers to Kerberos accounts, so we benefit from the central account administration. The actual authentication is handled by the webserver, which sets REMOTE_USER appropriately.

Demonstration: host records

130.102.93.10|platypus|Mark Suter|58221|42|411|ASI Pentium III|Linux||950083078|suter
130.102.93.11|bilby|Mark Suter|58221|42|411|Dell PowerEdge 6350|Linux||950083295|suter
130.102.93.12|bigred|Mark Suter|58221|42|411|Sun Ultra 5|Linux||950083295|suter
130.102.93.13||||||||||

Demonstration: WebDNS interface

• test2.uq.edu.au

Demonstration: forward zone file

$TTL 86400

@       IN      SOA     cuscus.cc.uq.edu.au. hostmaster.cc.uq.edu.au. (
                        2000020902      ; Serial
                        10800           ; Refresh
                        1800            ; Retry 
                        3600000         ; Expire
                        3600 )          ; RFC 2308 negative cache TTL
        IN      NS      cuscus.cc.uq.edu.au.
        IN      NS      krefti.cc.uq.edu.au.
        IN      MX      0       bunyip.cc.uq.edu.au.

localhost       IN      A       127.0.0.1

bigserver       IN      A       130.102.93.1
; User: Mr Big                  Phone: 112
; Building: AAPT                Room: MR3
; Hardware: Starfire            Operating System: Solaris

platypus        IN      A       130.102.93.10
bilby           IN      A       130.102.93.11
bigred          IN      A       130.102.93.12

Demonstration: reverse zone file

$TTL 86400

@       IN      SOA     cuscus.cc.uq.edu.au. hostmaster.cc.uq.edu.au. (
                        2000020902      ; Serial
                        10800           ; Refresh
                        1800            ; Retry 
                        3600000         ; Expire
                        3600 )          ; RFC 2308 negative cache TTL
        IN      NS      cuscus.cc.uq.edu.au.
        IN      NS      krefti.cc.uq.edu.au.

1       IN      PTR     bigservers.test2.uq.edu.au.

10      IN      PTR     platypus.test2.uq.edu.au.
11      IN      PTR     bilby.test2.uq.edu.au.
12      IN      PTR     bigred.test2.uq.edu.au.

Future Directions

• There is a possibility that we may use Lucent's QIP Enterprise or similar in the future.
• WebDNS v2.0 may be developed.

WebDNS v2.0

• The following items are on the wish list
• Use ndc reload <zone> effectively.
• Perform more frequent remakes - currently once per hour.
• Redesign the front end, possibly in PHP.

More information

• Please visit the DNS Resources Directory at http://www.dns.net/dnsrd/. This site contains links to the most useful DNS-related sites on the Internet.
• For information on the Apache webserver, go to http://www.apache.org/httpd.html.
• The homepage for the Internet Software Consortium's BIND is at http://www.isc.org/products/BIND/.

Thank-you.

Are there any more questions?

Self Reference

• This is available on the web at the following addresses.
  • As a single page at http://www.uq.edu.au/~suter/talks/webdns/; and
  • as slides, starting at http://www.uq.edu.au/~suter/talks/webdns/slide1.html.