
The default behavior in the libresolv.so.2 (BIND 4.9.3)  resolver
library  is to initially regard any host name containing at least
one dot as fully qualified. Hence, if  the  DNS  domain  name  is
"a.b.c",  and  the  resolver  library  is asked to resolve "x.y",
libresolv.so.2 will generate searches in the following order:

x.y x.y.a.b.c x.y.b.c

The old libresolv.so.1 (BIND 4.8.3) would have used  a  different
order:

x.y.a.b.c x.y.b.c x.y

Normally, the final result will be the same. However, if desired,
the  "ndots"  option  can be used to change the search order. For
example, by adding the line

options ndots:2

to /etc/resolv.conf, or by setting  the  RES_OPTIONS  environment
variable  to "ndots:2", at least two dots will be required before
a name is regarded as fully qualified. In the example above, this
means   that   libresolv.so.2  uses  the  same  search  order  as
libresolv.so.1.

For further information, see the cat manpages that came with this
patch -- IN.NAMED, NAMED-XFER, NSLOOPUP, RESOLVER and RESOLV.CONF.

