2.11bsd unix resolver
Maciej W. Rozycki
macro at linux-mips.org
Sun May 24 10:56:47 CDT 2020
On Thu, 21 May 2020, Richard Sheppard via cctalk wrote:
> On Solaris it’s the “hosts” line in the /etc/nsswitch.conf/ file.
Having /etc/nsswitch.conf was actually Solaris's invention and Solaris
itself came from System V rather than BSD. It was only adopted by the
freely available *BSD systems much later.
> Perhaps something similar in BSD.
Ultrix as a sole notable exception had /etc/svc.conf, and anyway with a
BSD version as early as 2.11 I'd expect the resolver's sequence of queries
to be hardcoded.
Perhaps the source of the problem is something as silly as the use of
<CR>+<LF> as line endings in /etc/hosts, causing the entry for 127.0.0.1
to correspond to `localhost^M' rather than expected `localhost' (a common
and confusing issue with shebang scripts imported or transmitted over FTP
in the binary rather than text mode from a foreign system causing an error
./myscript.sh: No such file or directory
$ ls -l ./myscript.sh
-rwxr-xr-x 1 macro macro 251 Jan 1 1970 ./myscript.sh
$ head -1 ./myscript.sh
$ # Hmm...
For the record older versions of Linux (up to libc 5), including a.out
ones in particular, used /etc/host.conf to configure the resolver.
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