Bug 202617 – /proc/sys/kernel/domainname not set

• Product: Gentoo Linux
• Status: RESOLVED INVALID

[Description John Huttley 2007-12-17 20:31:49 UTC]

This is one of the variables setable by sysctl.conf.
You can set your dnsdomain name  in /etc/conf.d/net, and /bin/dnsdomainname may give the correct answer, but that variable is left as empty.

Does this actually matter to anything?

Reproducible: Always

Steps to Reproduce:
1. sysctl -a | grep name
2.
3.

Actual Results:  
its possible to manually set it, but again, it doesn't seem to do anything.

[Comment 1 SpanKY 2007-12-18 07:51:26 UTC]

the standard kernel syscalls that the standard utilities make when setting the hostname/domainname take care of updating the internal variables that the /proc/sys/ interface exposes.  there's no point in setting them in two places when one already updates the other.

[Comment 2 John Huttley 2007-12-19 04:19:19 UTC]

(In reply to comment #1)
> the standard kernel syscalls that the standard utilities make when setting the
> hostname/domainname take care of updating the internal variables that the
> /proc/sys/ interface exposes.  there's no point in setting them in two places
> when one already updates the other.
> 
This turns out not to be the case.
It's easy to show.

Case #1.
set your dns name in /etc/conf.d/net
reboot and confirm that it is set by running /bin/dnsdomainname.

cat /proc/sys/kernel/domainname
to get (none)

Case #2
remove dns name from /etc/conf.d/net and /etc/resolv.conf
reboot and confirm that it is not set by running /bin/dnsdomainname.
(returns Unknown Host)

Then edit /etc/sysctl.conf 
kernel.domainname=example.com

and reboot
/bin/dnsdomainname  still returns Unknown Host

cat /proc/sys/kernel/domainname
gives example.com


Conclusion: They don't share internal state.
So whats it for?
Regards,
john

[Comment 3 SpanKY 2007-12-19 11:47:31 UTC]

you arent comparing apples to apples

# domainname f
# cat /proc/sys/kernel/domainname
f