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- Steps to take when undertaking DNS modifications:
-
- - No need to worry about SOA serial numbers -- these are updated
- automatically (using RCS revision information) if any relative
- data has been modified.
-
- - Use RCS for all modifications. The automatic SOA serial number
- generation depends on _all_ DNS config files containing an RCS
- "Id" string.
-
- - Are you adding a zone? -- If so, your file should be called
- <something>.zone, and it should $INCLUDE a file called
- <something>.SOA, and probably at least NS.generic. Then you need
- to add some "nameserver delegations" (NS entries for
- authoritative nameservers) to the parent zone (see
- example.org.au/top.zone for more information). Use another .zone
- file as an example.
-
- You will need to add mention of your zone file to the Makefile.
- Also, you will need to add it to named.boot.
-
- - Do you want to add the "standard" set of MX records for a node?
- -- Use an $INCLUDE like the following:
-
- ; ORIGIN is currently sub.example.org.au.
- red IN A 191.254.1.10
- IN HINFO Sun-SS2 SunOS
- $INCLUDE MX.generic red
-
- The "red" on the end of the $INCLUDE statement sets the ORIGIN
- to "red.sub.example.org.au." for the contents of the INCLUDE-ed
- file.
-
- - Have you added any new files? -- add them to the correct
- variable(s) in the Makefile and run "make depend".
-
- - Have you added/removed/changed any $INCLUDE directives in any of
- the files? -- Run "make depend".
-
- - Do you want to install your changes? -- Run "make install". This
- will install any files that have been modified since the last
- "make install".
-
- - Do you want "named" to start using your changes? -- Run
- "make configure". The "configure" target does an implicit
- "install", so if you want to install and configure, you only need
- to use "make configure".
-
- You should check the startup/reload messages from named to check
- that your changes are OK. Use the following command on your
- primary server:
-
- $ grep named /var/adm/messages | tail -50
-
- If everything is OK, you should (eventually) see something like:
-
- Jul 21 12:53:27 ns named[103]: reloading nameserver
- Jul 21 12:53:43 ns named[103]: Ready to answer queries.
-
- - Do you want to clean up any temporary files? -- Run "make clean".
-
-
- Rules for DNS data:
-
- - If a particular zone ("red.sub.example.org.au", "sub.example.org.au"
- and "example.org.au" are all zones) is to have a CNAME entry, it
- can not have any other entries (as this would not make sense).
- If you want "sub.example.org.au" to be an alias for
- "white.sub.example.org.au" use the following:
-
- ; ORIGIN is currently "sub.example.org.au."
- @ IN A (the IP-address for white)
- IN HINFO CNAME white.sub.example.org.au.
-
- - All A records should have corresponding PTR records in an
- IN-ADDR.ARPA zone. In other words, software using DNS should be
- able to find retrieve any hostname, given a valid IP address.
-
- - All PTR records should refer to an A record that exists. In
- other words, if you are given a valid IP address, you should be
- able to fetch a hostname via a PTR lookup, then re-fetch any IP
- addresses via an A lookup.
-
- PTR records that refer to CNAME's are bogus.
-
- - All CNAME records _should_ refer to a zone that has an A record.
- I don't know whether it is useful to have an alias for a zone
- that does not have any A records, but they should at least refer
- to a valid zone.
-
- - If a host has more than one IP address (perhaps it is a
- gateway), all PTR records for those addresses should refer to the
- same hostname, which is the offical name for that host. If a
- specific interface on a host needs to be referred to, a seperate A
- record can be used to do this, but the corresponding PTR record
- should still refer to the official hostname.
-
- You may find instances where software does not like this
- configuration (NIS on Sun's, which can only return one address
- for a hostname can cause problems - use DNS if you have Solaris
- 2), but it is recognised on the Internet as the proper thing to
- do.
-
- An example, for illustration:
-
- ; ORIGIN is currently sub.example.org.au
- yellow IN A 191.254.16.1
- IN A 191.254.17.1
- yellow-i1 IN A 191.254.16.1
- yellow-i2 IN A 191.254.17.1
- ;
- 1.16.254.191.IN-ADDR.ARPA. IN PTR yellow
- 1.17.254.191.IN-ADDR.ARPA. IN PTR yellow
-
- - "named" is picky about HINFO records. They must contain two
- values (which are usually interpreted as make/model followed by
- operating-system), separated by whitespace. If you want to put
- whitespace in one of the values, quote it. If you have a HINFO
- record that does not match this format, named will get messed up.
- Here are some examples:
-
- ; These are OK
- foo IN HINFO Sun-SS2 SunOS
- bar IN HINFO Spagthorpe "GSZXBRRF2 750RR"
- snafu IN HINFO Sun-3/60 Sun-Xkernel
- ; These are NOT
- ding IN HINFO Microwave
- hiss IN HINFO Stainless-Steel Hot Water Urn
- ahhhhh IN HINFO Coin-operated Coke Vending-Machine
-
- --
- Tim Cook
- Systems Engineer
- Computing & Communications Services
- Deakin University
-