It seems that i can ping google DNS to its IPv6 address 2001:4860:4860::8888 but i can't ping it's IPv4 address

luka@luka-Inspiron-3458:~$ ping
PING ( 56(84) bytes of data.
--- ping statistics ---
173 packets transmitted, 0 received, 100% packet loss, time 173374ms

luka@luka-Inspiron-3458:~$ ping6 2001:4860:4860::8888
PING 2001:4860:4860::8888(2001:4860:4860::8888) 56 data bytes
64 bytes from 2001:4860:4860::8888: icmp_seq=1 ttl=48 time=286 ms
64 bytes from 2001:4860:4860::8888: icmp_seq=2 ttl=48 time=60.6 ms    
64 bytes from 2001:4860:4860::8888: icmp_seq=3 ttl=48 time=61.3 ms
64 bytes from 2001:4860:4860::8888: icmp_seq=4 ttl=48 time=60.8 ms
64 bytes from 2001:4860:4860::8888: icmp_seq=5 ttl=48 time=60.9 ms
64 bytes from 2001:4860:4860::8888: icmp_seq=6 ttl=48 time=60.2 ms
64 bytes from 2001:4860:4860::8888: icmp_seq=7 ttl=48 time=59.5 ms
64 bytes from 2001:4860:4860::8888: icmp_seq=8 ttl=48 time=60.8 ms
--- 2001:4860:4860::8888 ping statistics ---
8 packets transmitted, 8 received, 0% packet loss, time 7010ms
rtt min/avg/max/mdev = 59.573/88.846/286.406/74.672 ms

i have a really slow internet conection in this laptop (i'm using Ubuntu 16.04), pages take literal hours to load and sometimes it ends with "Site Can't be Reached", and i believe it's because of this issue. I also can't ping my router's IP which is Every other PC in my house uses the internet with no problem, even the same laptop, when i boot on windows, connects without any issues.

output of cat /etc/network/interfaces

luka@luka-Inspiron-3458:~$ cat /etc/network/interfaces 
 # interfaces(5) file used by ifup(8) and ifdown(8)
 auto lo
 iface lo inet loopback

output of ifconfig:

eth0      Link encap:Ethernet  HWaddr 20:47:47:29:b9:98
          UP BROADCAST MULTICAST  MTU:1500  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
         RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)

lo        Link encap:Local Loopback
          inet addr:  Mask:
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:65536  Metric:1
          RX packets:11920 errors:0 dropped:0 overruns:0 frame:0    
          TX packets:11920 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1
          RX bytes:778490 (778.4 KB)  TX bytes:778490 (778.4 KB)

wlan0     Link encap:Ethernet  HWaddr b4:6d:83:9b:1d:6f      
        inet addr:  Bcast:  Mask:    
          inet6 addr: 2806:10a6:5:177c:b66d:83ff:fe9b:1d6f/64 Scope:Global
          inet6 addr: 2806:10a6:5:177c:c61:441f:5f13:8edf/64 Scope:Global
          inet6 addr: fe80::b66d:83ff:fe9b:1d6f/64 Scope:Link
          RX packets:9990 errors:0 dropped:0 overruns:0 frame:0
          TX packets:11766 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:586026 (586.0 KB)  TX bytes:1298218 (1.2 MB)

output iwconfig:

lo        no wireless extensions.

wlan0     IEEE 802.11abgn  ESSID:"INFINITUM0368"  
          Mode:Managed  Frequency:2.462 GHz  Access Point: E4:3E:D7:3B:1B:42   
          Bit Rate=72.2 Mb/s   Tx-Power=20 dBm   
          Retry short limit:7   RTS thr:off   Fragment thr:off
          Power Management:on
          Link Quality=69/70  Signal level=-41 dBm  
          Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0
          Tx excessive retries:0  Invalid misc:521   Missed beacon:0

eth0      no wireless extensions.

output of cat /etc/resolv.conf

luka@luka-Inspiron-3458:/etc/init.d$ cat /etc/resolv.conf 
# Dynamic resolv.conf(5) file for glibc resolver(3) generated by resolvconf(8)
search rga.ip

output route -n

luka@luka-Inspiron-3458:~$ route -n
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface         UG    600    0        0 wlan0     U     1000   0        0 wlan0   U     0      0        0 vmnet0   U     0      0        0 vmnet8   U     0      0        0 vmnet1   U     600    0        0 wlan0

output from route -6 -n

luka@luka-Inspiron-3458:~$ route -6 -n
Kernel IPv6 routing table
Destination                    Next Hop                   Flag Met Ref Use If
2806:10a6:5:177c::/64          ::                         Ue   256 0     0 wlan0
fe80::/64                      ::                         U    256 0     0 vmnet0
fe80::/64                      ::                         U    256 0     0 vmnet1
fe80::/64                      ::                         U    256 0     0 vmnet8
fe80::/64                      ::                         U    256 4   271 wlan0
::/0                           fe80::1                    UG   600 3     9 wlan0
::/0                           ::                         !n   -1  1  2291 lo
::1/128                        ::                         Un   0   5    19 lo
2806:10a6:5:177c:8cb0:eddf:714e:872f/128 ::                         Un   0   2   179 lo
2806:10a6:5:177c:e3a2:3a53:f36d:2567/128 ::                         Un   0   1     0 lo
fe80::250:56ff:fec0:0/128      ::                         Un   0   1     0 lo
fe80::250:56ff:fec0:1/128      ::                         Un   0   1     0 lo
fe80::250:56ff:fec0:8/128      ::                         Un   0   1     0 lo
fe80::e97b:d589:3ece:1f53/128  ::                         Un   0   2   299 lo
ff00::/8                       ::                         U    256 4    69 vmnet0
ff00::/8                       ::                         U    256 4    61 vmnet1
ff00::/8                       ::                         U    256 4    61 vmnet8
ff00::/8                       ::                         U    256 4   221 wlan0
::/0                           ::                         !n   -1  1  2291 lo

output from ip neigh

luka@luka-Inspiron-3458:~$ ip neigh dev wlan0 lladdr e4:3e:d7:3b:1b:42 STALE
fe80::1 dev wlan0 lladdr e4:3e:d7:3b:1b:42 router STALE

IPv4 tab on Edit Connections... IPv4

Thanks everybody for your help.

migrated from serverfault.com Dec 19 '17 at 21:49

This question came from our site for system and network administrators.

  • Comments are not for extended discussion; this conversation has been moved to chat. – Journeyman Geek Dec 20 '17 at 1:45
  • Looks like you have a VMware network (with interface vmnet1) on the same subnet as your router ( Could you check that? – Dubu Jan 17 '18 at 15:07

Based on the information provided we can see that there is some compatibility problem between your Ubuntu 16.04 machine and your router. That somehow breaks IPv4 connectivity.

However given that you appear to have working IPv6 connectivity you can use that and NAT64 to access IPv4-only sites as well.

The steps to achieve that setup are as follows:

  • Click on the WiFi icon.
  • Click on Edit Connections...
  • Choose your SSID from the list.
  • Click on Edit...
  • Choose the IPv4 Settings tab
  • Change Method from Automatic to Disabled
  • Choose the IPv6 Settings tab
  • Change Method from Automatic to Automatic, addresses only
  • Fill in the DNS servers field with 2-3 DNS64 addresses

The above changes will only apply to the chosen SSID, which is the desired behavior as you likely only have the problem when connected to that specific router.

You will get the best latency if you find DNS64 addresses provided by your own ISP. But otherwise these two sites TREX and go6 Lab have 6 different public DNS64 addresses that you can use.

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