It is even 'worse'.
I had eth0 as onboard ethernet card in my laptop
and wlan0 as the wireless connection.
I was using cable connection on eth0 and it went
fine, for a while.
Then I enabled wlan0 AFTER disconnecting my eth0,
and days have passed and many reboots later I
tried to smbclient to a Win machine on my private
LAN and it was telling me that
Destination Host Unreachable
annoying message.
'Annoying', so to speak, the ping was not working
as well and as I pinged my network's 192.168.127.100
machine the inexistent 192.168.127.102 replied to me
with the same message that you reported.
The only difference is that your response is from
your own IP and mine well, not since my laptop is
103 but I'll unveil the remaining below:
Same with the gateway, but that ficticious 102 machine
was speaking endlessly. Even to IP's of external
websites (using the IP, not the Domain Name of the
external website which worked, but the IP which didn't)
the same behaviour took place.
Then I read this post and very strangely I just
happened to go seeing with ifconfig like you did
and I saw that eth0, without any cable had it's
IP (damned be
192.168.127.102!!!!!!!
Then I immediately did
sudo ifdown eth0
and pinged through my wireless connection, now
certainly the unique one enabled.
And YES! The annonying behaviour is gone and
the machine 100 replied well with its 192.168.127.100
address and samba now is up :-)
Conclusion:
Never leave an 'up' connection without the cable.
If it is unplugged make sure you ifdown <iface>
the <iface> that hasn't any cable attached to it
as the internal Linux routing may go nuts lol
It worked for me, I hope it works for you.
It could be what broch told too, if you want
to have 2 interfaces plugged, not all routers
might support this. But it is not likely, since
an interface is handled independently by your
(external) router. I think it has to do with
internal Linux routing and the way you forget
or not to activate/deactivate via software the
interfaces etc. accordingly to the hardware
status (is the cable connected?). I think all
things must be conformant. E.g.: If there is
not a cable plugged to the interface it MUST
>>NOT<< be 'up' otherwise something might happen
like the one that I experienced.