[gentoo-user] Strange behaviour of dhcpcd

[Marc Joliet <marcec@gmx.de>]

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Hi list

First off: this is a "fixed" issue, in that I don't see the behaviour anymore,
so time is not of the essence ;) . I'm only looking for an explanation, or for
comments from other people who experienced this.

So the issue was some really strange behaviour on the part of dhcpcd.  I
completed a move a few weeks ago and got an internet connection last Wednesday
(using a local cable company, that is, using a cable modem connected to via
ethernet). I reconfigured my system to use regular DHCP (a relief after the
PPPoE mess in the dorm), but dhcpcd could not apply the default route; it
*obtained* one, but failed with "if_addroute: Invalid argument". I tried it
manually, to no effect: "ip route" complained about invalid arguments, and I
think plain "route" said "file exists", but I'm not sure anymore (either way,
the error messages were less than clear).  The funny thing is, I *could* set
the default route, just not to the one advertised via DHCP, but to the x.y.z.2+
instead of x.y.z.1, which even gave me access to the internet part of the time.

Now the funny thing is what fixed it:
 
  *commenting out the entirety of /etc/dhcpcd.conf*

Then dhcpcd ran with   default settings and could apply the default route. Even
more bizarre is the fact that it kept working after uncommenting it again (and
I track it with git, so I'm 100% sure I got it back to its original state).
This leads me to believe that there was some (corrupted?) persistent state
somewhere that got overwritten by starting dhcpcd after I commented out the
file, but I have no clue where.

Has anyone seen this sort of behaviour before, or anything similar to it?  I
searched for the error messages I was seeing, but couldn't find anything.  I
was using gentoo-sources-3.15.9 (now I'm at 3.16.6) and dhcpcd 6.4.3 at the
time, but also had the issue with dhcpcd 6.4.7, to which I could upgrade by
using the aforementioned x.y.z.2 gateway. Perhaps it was a bug in the kernel?
But that's just guessing.

Regards,
-- 
Marc Joliet
--
"People who think they know everything really annoy those of us who know we
don't" - Bjarne Stroustrup

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