Bug 144700

Description Dmitry Marakasov 2010-03-12 16:40:01 UTC

Recently I've seen just too many cases when the default way dhclient
is ran breaks stuff for people (samba, ntpd, other services don't start
with lots of errors, because resolving or routes are not set up), so,
though there exists related conf/133987, I though this should be
submitted again with critical status.

As far as I remember, the reason we don't have synchronous_dhclient="YES"
by default (which will fix things for all these people) is for the sake
of mobile users who don't always have interfaces up on boottime.

However I don't believe we have more mobile than stationary users, so to
benefit most I think we should at have synchronous_dhclient="YES" by
default. In addition, this setting is much easier to debug - as dhclient
popping up on boot when it's not desired, leads to obvious conclusion
that it should be turned off, while current setting leads to many
services failing randomly, without obvious relation to DHCP - for example,
ntpd is unable to resolve any server addresses and ends up without peers,
doing nothing. Unless you look into logs, you won't even know it's not
working.

Fix: 

First thing, we definitely need to have synchronous_dhclient="YES" by default.

Additional changes may be useful for mobile users, for example, something
like this:

http://www.mail-archive.com/svn-src-all@freebsd.org/msg08127.html

Finally, we may think of some solution that delays service startups
until networking is up. Not sure if that can really be useful though.
How-To-Repeat: Setup services that need networking (resolving, most commonly) at startup.
Run them on DHCP-enabled system, watch them fail because by the time
they're run, networking is not set up yet.