Configuring and Managing MPE/iX Internet Services (MPE/iX 6.5)
Chapter 8 127
DNS BIND/iX
Data Files
news IN CNAME nova.maxx.net.
mail IN CNAME nova.maxx.net.
ns IN CNAME nova.maxx.net.
loghost IN CNAME nova.maxx.net.
lucy IN A 204.251.17.242
linux IN CNAME lucy.maxx.net.
lucy IN MX 10 lucy.maxx.net.
messdos IN A 204.251.17.243
messdos IN MX 10 messdos.maxx.net.
pentium IN CNAME messdos.maxx.net.
solaris IN A 204.251.17.244
solaris IN MX 10 solaris.maxx.net.
maxx4 IN CNAME solaris.maxx.net.
maxx5 IN A 204.251.17.245
maxx5 IN MX 10 maxx5.maxx.net.
maxx6 IN A 204.251.17.246
maxx6 IN MX 10 maxx6.maxx.net.
Most database file entries are known as DNS resource records.
Generally, the resource records are shown in order: SOA, NS, followed
by the other types, but this ordering isn’t required. The data in each
entry may be entered in upper, lower, or mixed case. All entries in the
database file must start at the beginning of the line. Blank lines as well
as any text following a semicolon is ignored.
SOA stands for Start of Authority. This acronym notifies named that
operational parameters follow. The most important one is the Serial
field. Every time you make a change to a database file, you must
increment its serial number. Only by doing this will secondary servers
know they need to reach into your system and pull out new name server
data, a procedure known as a “zone transfer.” Many DNS
administrators use a date-time stamp for this field, like 9602171 for the
first version on February 17, 1996.
First, focus on the SOA section:
maxx.net. IN SOA nova.maxx.net. tyager.maxx.maxx.net.
The “maxx.net.” field tells named the domain defined by this file. The
name server will automatically append it to any host name that
appears in the file. The trailing dot is not a type; it keeps named from
trying to tack on your domain name. Without it, the resolver would be
confused by named’s expansion of my domain name to
“maxx.net.maxx.net.”
The IN stands for the “Internet” class of data. Even though other
classes exist, they aren’t in common usage. The “nova.maxx.net” field
is the host on which these database files reside. Finally,
“tyager.nova.maxx.net” represents the e-mail address of the DNS
administrator, where the first dot (between tyager and nova) would be
replaced by the @ symbol to create a valid address. (The @ symbol can’t
be used here because it has a reserved meaning in DNS database files.)