Connection looks heathy but no Internet

Question

I recently updated Ubuntu 16.04/64 and during several days switched between few networks (I was traveling last week). Now back home and cannot get any Internet connection - neither Ethernet nor Wifi. Whatever I did following the advices on stackoverflow etc, nothing does work. Moreover, after updating the second machine with the same OS lost Wifi connectivity, although Ethernet is working. The disease has the following symptoms:

1. Connection is easy to setup (both Ethernet and Wifi) and it looks healthy, but there is no Internet. Reboot/restart does not help.

2. Ip6 was assigned although I set it to "Ignore".

3. Some outputs (for Ethernet only setup):

$ ifconfig

enp1s0 Link encap:Ethernet HWaddr XX:XX:XX:XX:XX:XX

      inet addr:192.168.0.115  Bcast:192.168.0.255  Mask:255.255.255.0

      inet6 addr: XXXX::XXXX:XXXX:XXXX:XXXX/64 Scope:Link

      UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1

      RX packets:22 errors:0 dropped:0 overruns:0 frame:0

      TX packets:45 errors:0 dropped:0 overruns:0 carrier:0

      collisions:0 txqueuelen:1000 

      RX bytes:3455 (3.4 KB)  TX bytes:5608 (5.6 KB)

lo Link encap:Local Loopback

      inet addr:127.0.0.1  Mask:255.0.0.0

      inet6 addr: ::1/128 Scope:Host

      UP LOOPBACK RUNNING  MTU:65536  Metric:1

      RX packets:577 errors:0 dropped:0 overruns:0 frame:0

      TX packets:577 errors:0 dropped:0 overruns:0 carrier:0

      collisions:0 txqueuelen:1

      RX bytes:39066 (39.0 KB)  TX bytes:39066 (39.0 KB)

$ route

Kernel IP routing table Destination Gateway Genmask Flags Metric Ref Use Iface

default gateway 0.0.0.0 UG 100 0 0 enp1s0

link-local * 255.255.0.0 U 1000 0 0 enp1s0

192.168.0.0 * 255.255.255.0 U 100 0 0 enp1s0

$ ping 8.8.8.8

PING 8.8.8.8 (8.8.8.8) 56(84) bytes of data.

ping: sendmsg: Operation not permitted

ping: sendmsg: Operation not permitted

ping: sendmsg: Operation not permitted

--- 8.8.8.8 ping statistics ---

3 packets transmitted, 0 received, 100% packet loss, time 2014ms

$ cat /etc/network/interfaces

auto lo

iface lo inet loopback

$ iwconfig

lo no wireless extensions.

enp1s0 no wireless extensions.

wlp2s0 IEEE 802.11bgn ESSID:off/any

      Mode:Managed  Access Point: Not-Associated   Tx-Power=off

      Retry short limit:7   RTS thr:off   Fragment thr:off

      Power Management:off

$ ping www.google.com

ping: unknown host www.google.com

$ mtr

mtr: unable to get raw sockets.

$ cat /etc/resolv.conf

nameserver 127.0.1.1

search home

I would appreciate step by step instructions how to revive the system. I need to travel once again and full re-installation is the worst option in this case.

Answer 1

Googling for ping: sendmsg: Operation not permitted suggests that this is probably an issue with iptables blocking outbound packets:

https://serverfault.com/questions/372975/ping-sendmsg-operation-not-permitted-error-after-installing-iptables-on-arch-g