Re: RPI using recent image boots with non functioning gateway

[Andy Ruhl <acruhl%gmail.com@localhost>]

On Wed, Dec 16, 2015 at 6:26 AM, Roy Marples <roy%marples.name@localhost> wrote:
> On 16/12/2015 13:55, Andy Ruhl wrote:
>> rpi# ping www.netbsd.org
>> ping: Cannot resolve "www.netbsd.org" (Host name lookup failure)
>> rpi# netstat -rn -f inet
>> Routing tables
>>
>> Internet:
>> Destination        Gateway            Flags    Refs      Use    Mtu Interface
>> default            192.168.0.254      UGS         -        -      -  axe0
>> 127/8              127.0.0.1          UGRS        -        -  33192  lo0
>> 127.0.0.1          lo0                UHl         -        -  33192  lo0
>> 192.168.0/24       link#2             UC          -        -      -L axe0
>> 192.168.0.254      fa:ke:ma:ca:dd:rr  UHLc        -        -      -L axe0
>
> Looks fine.
> At this point does ping 192.168.0.254 work?
> If not, I see you masked out the MAC address of the router .... but can
> you verify it is correct?
> Also, does ping 8.8.8.8 work?
>
> Trying to work out if DNS or routing is the one failing here.
> Can you tell us if you have any special DNS configured?
> What do `resolvconf -l` and `dhcpcd -U4 axe0 | grep domain` show?

Some more info. To get the machine into the "bad" state, I'm rebooting
it. I just rebooted it and pings to outside addresses worked fine.
Then I rebooted again and it's back to the "bad" state. So it seems a
little random.

Some answers (from the bad state):

rpi# ping 8.8.8.8
PING 8.8.8.8 (8.8.8.8): 56 data bytes
^C
----8.8.8.8 PING Statistics----
3 packets transmitted, 0 packets received, 100.0% packet loss
rpi# ping 192.168.0.254
PING 192.168.0.254 (192.168.0.254): 56 data bytes
64 bytes from 192.168.0.254: icmp_seq=0 ttl=64 time=0.698971 ms
64 bytes from 192.168.0.254: icmp_seq=1 ttl=64 time=0.757969 ms
^C
----192.168.0.254 PING Statistics----
2 packets transmitted, 2 packets received, 0.0% packet loss
round-trip min/avg/max/stddev = 0.698971/0.728470/0.757969/0.041718 ms
rpi# resolvconf -l
# resolv.conf from axe0.dhcp
# Generated by dhcpcd from axe0.dhcp
domain andy.home
search andy.home
nameserver 68.105.28.11
nameserver 68.105.29.11
nameserver 68.105.28.12

rpi# ping 68.105.28.11
PING 68.105.28.11 (68.105.28.11): 56 data bytes
^C
----68.105.28.11 PING Statistics----
3 packets transmitted, 0 packets received, 100.0% packet loss
rpi# dhcpcd -U4 axe0 | grep domain
axe0: dhcp_dump: No such file or directory
rpi# ping 8.8.8.8
PING 8.8.8.8 (8.8.8.8): 56 data bytes
^C
----8.8.8.8 PING Statistics----
2 packets transmitted, 0 packets received, 100.0% packet loss
rpi# route delete 0.0.0.0/0 192.168.0.254
delete net 0.0.0.0: gateway 192.168.0.254
rpi# route add default 192.168.0.254
add net default: gateway 192.168.0.254
rpi# ping 8.8.8.8
PING google-public-dns-a.google.com (8.8.8.8): 56 data bytes
64 bytes from 8.8.8.8: icmp_seq=0 ttl=54 time=31.946659 ms
64 bytes from 8.8.8.8: icmp_seq=1 ttl=54 time=25.406958 ms
^C
----google-public-dns-a.google.com PING Statistics----
2 packets transmitted, 2 packets received, 0.0% packet loss
round-trip min/avg/max/stddev = 25.406958/28.676808/31.946659/4.624267 ms

Seems like some IP stack internal issue to me. I could try setting a
static address and rebooting a few times to see if it happens I
suppose. It seems unlikely to be a dhcpcd issue given that it works
everywhere else.

Andy