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I now know it is not a DNS issue, because I can't even ping 8.8.8.8. I've added the output of tracepath 8.8.8.8.

My machine running the most up-to-date version of 14.04 Trusty. The mobo has two ethernet ports and a Wi-Fi card. Both ethernet ports are plugged in. One goes directly into the router and has a static IP address. The other is plugged into a network switch and is DHCP. This machine was a fresh installation and has had DNS issues from the get-go. It's located in Texas, I'm in Denver, and I am controlling it remotely through Teamviewer so I know some outgoing/incoming traffic gets through. Other machines on the same network have no networking issues.

Symptoms:

  • Cannot load websites by name (google.com) or IP (64.233.177.103)
  • Cannot use sudo apt-get, times out connecting to servers
  • Cannot ping WAN IPs. Pinging 8.8.8.8 gets no response and 100% packet loss.
  • Can ping LAN IPs.
  • Can load router config page in web browser through LAN IP.
  • Allows Teamviewer remote connection. UDP does not seem to work, TCP works ok but I get kicked out regularly.

Troubleshooting steps taken so far:

  • Power cycled machine
  • Unplugged/Replugged both network cables
  • Changed connection type to DHCP, and back to static, for both ports through network settings GUI. Currently one is static and the other is DHCP.
  • Factory defaulted router and upgraded to latest firmware (Luxul XBR-4400)
  • Restarted Networking Service
  • Restarted network-manager
  • Tried adding static IP manually through /etc/network/interfaces. Made it match what I had set through GUI.
  • Bypassed local nameservers per this answer: Should I edit my resolv.conf file to fix wrong DNS problem?
    • This involved commenting out the dns=dnsmasq line in /etc/NetworkManager/NetworkManager.conf.
    • Running Sudo restart network-manager changed my /etc/resolv.conf file

from this:

# Dynamic resolv.conf(5) file for glibc resolver(3) generated by resolvconf(8)
#     DO NOT EDIT THIS FILE BY HAND -- YOUR CHANGES WILL BE OVERWRITTEN
nameserver 127.0.0.1
search lan

to this:

# Dynamic resolv.conf(5) file for glibc resolver(3) generated by resolvconf(8)
#     DO NOT EDIT THIS FILE BY HAND -- YOUR CHANGES WILL BE OVERWRITTEN
nameserver 192.168.8.1
nameserver 75.75.75.75
nameserver 8.8.8.8
search lan
  • I still get the same exact symptoms. DNS and static IP's have been configured through GUI.

Running nslookup www.google.com gets me a normal looking output, so nslookup seems to work (along with Teamviewer). However loading www.google.com or a direct IP for www.google.com (64.233.177.147) does not work.

Output of nslookup www.google.com:

Server:     192.168.8.1
Address:    192.168.8.1#53

Non-authoritative answer:
Name:   www.google.com
Address: 64.233.177.147
Name:   www.google.com
Address: 64.233.177.104
Name:   www.google.com
Address: 64.233.177.99
Name:   www.google.com
Address: 64.233.177.105
Name:   www.google.com
Address: 64.233.177.103
Name:   www.google.com
Address: 64.233.177.106

Output of /etc/network/interfaces:

# interfaces(5) file used by ifup(8) and ifdown(8)
auto lo
iface lo inet loopback

Output of nmcli dev list iface eth0 (eth0 is static)

GENERAL.DEVICE:                         eth0
GENERAL.TYPE:                           802-3-ethernet
GENERAL.VENDOR:                         Realtek Semiconductor Co., Ltd.
GENERAL.PRODUCT:                        Motherboard
GENERAL.DRIVER:                         r8169
GENERAL.DRIVER-VERSION:                 2.3LK-NAPI
GENERAL.FIRMWARE-VERSION:               rtl8168g-2_0.0.1 02/06/13
GENERAL.HWADDR:                         FC:AA:14:E5:55:DD
GENERAL.STATE:                          100 (connected)
GENERAL.REASON:                         0 (No reason given)
GENERAL.UDI:                            /sys/devices/pci0000:00/0000:00:1c.3/0000:04:00.0/net/eth0
GENERAL.IP-IFACE:                       eth0
GENERAL.NM-MANAGED:                     yes
GENERAL.AUTOCONNECT:                    yes
GENERAL.FIRMWARE-MISSING:               no
GENERAL.CONNECTION:                     /org/freedesktop/NetworkManager/ActiveConnection/3
CAPABILITIES.CARRIER-DETECT:            yes
CAPABILITIES.SPEED:                     1000 Mb/s
CONNECTIONS.AVAILABLE-CONNECTION-PATHS: /org/freedesktop/NetworkManager/Settings/{0}
CONNECTIONS.AVAILABLE-CONNECTIONS[1]:   29935289-bf46-4dcf-89a0-b282fa8b3f69 | Wired connection 2
WIRED-PROPERTIES.CARRIER:               on
IP4.ADDRESS[1]:                         ip = 192.168.8.99/24, gw = 192.168.8.1
IP4.DNS[1]:                             192.168.8.1
IP4.DNS[2]:                             75.75.75.75
IP4.DNS[3]:                             8.8.8.8

Output of nmcli dev list iface eth1 (eth1 is DHCP)

GENERAL.DEVICE:                         eth1
GENERAL.TYPE:                           802-3-ethernet
GENERAL.VENDOR:                         Intel Corporation
GENERAL.PRODUCT:                        Ethernet Connection I217-V
GENERAL.DRIVER:                         e1000e
GENERAL.DRIVER-VERSION:                 2.3.2-k
GENERAL.FIRMWARE-VERSION:               0.13-4
GENERAL.HWADDR:                         FC:AA:14:E5:55:DB
GENERAL.STATE:                          100 (connected)
GENERAL.REASON:                         0 (No reason given)
GENERAL.UDI:                            /sys/devices/pci0000:00/0000:00:19.0/net/eth1
GENERAL.IP-IFACE:                       eth1
GENERAL.NM-MANAGED:                     yes
GENERAL.AUTOCONNECT:                    yes
GENERAL.FIRMWARE-MISSING:               no
GENERAL.CONNECTION:                     /org/freedesktop/NetworkManager/ActiveConnection/2
CAPABILITIES.CARRIER-DETECT:            yes
CAPABILITIES.SPEED:                     1000 Mb/s
CONNECTIONS.AVAILABLE-CONNECTION-PATHS: /org/freedesktop/NetworkManager/Settings/{2}
CONNECTIONS.AVAILABLE-CONNECTIONS[1]:   117aa4b3-1265-468e-b07d-d3c8998b14ea | Wired connection 1
WIRED-PROPERTIES.CARRIER:               on
IP4.ADDRESS[1]:                         ip = 192.168.8.141/24, gw = 192.168.8.1
IP4.DNS[1]:                             192.168.8.1
IP4.DOMAIN[1]:                          lan
DHCP4.OPTION[1]:                        host_name = nimbus-NS150
DHCP4.OPTION[2]:                        domain_name = lan
DHCP4.OPTION[3]:                        expiry = 1439959400
DHCP4.OPTION[4]:                        broadcast_address = 192.168.8.255
DHCP4.OPTION[5]:                        dhcp_message_type = 5
DHCP4.OPTION[6]:                        dhcp_lease_time = 43200
DHCP4.OPTION[7]:                        ip_address = 192.168.8.141
DHCP4.OPTION[8]:                        subnet_mask = 255.255.255.0
DHCP4.OPTION[9]:                        dhcp_renewal_time = 21600
DHCP4.OPTION[10]:                       routers = 192.168.8.1
DHCP4.OPTION[11]:                       dhcp_rebinding_time = 37800
DHCP4.OPTION[12]:                       domain_name_servers = 192.168.8.1
DHCP4.OPTION[13]:                       network_number = 192.168.8.0
DHCP4.OPTION[14]:                       dhcp_server_identifier = 192.168.8.1

Output of ifconfig -a:

eth0      Link encap:Ethernet  HWaddr fc:aa:14:e5:55:dd  
          inet addr:192.168.8.99  Bcast:192.168.8.255  Mask:255.255.255.0
          inet6 addr: fe80::feaa:14ff:fee5:55dd/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:331544 errors:0 dropped:2390 overruns:0 frame:0
          TX packets:132548 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:43753936 (43.7 MB)  TX bytes:67745643 (67.7 MB)

eth1      Link encap:Ethernet  HWaddr fc:aa:14:e5:55:db  
          inet addr:192.168.8.141  Bcast:192.168.8.255  Mask:255.255.255.0
          inet6 addr: fe80::feaa:14ff:fee5:55db/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:839361 errors:0 dropped:0 overruns:0 frame:0
          TX packets:1113669 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:85882847 (85.8 MB)  TX bytes:427516880 (427.5 MB)
          Interrupt:20 Memory:f7e00000-f7e20000 

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:2373781 errors:0 dropped:0 overruns:0 frame:0
          TX packets:2373781 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0 
          RX bytes:623910191 (623.9 MB)  TX bytes:623910191 (623.9 MB)

wlan0     Link encap:Ethernet  HWaddr ac:fd:ce:47:1e:77  
          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)

Pinging my router:

PING 192.168.8.1 (192.168.8.1) 56(84) bytes of data.
64 bytes from 192.168.8.1: icmp_seq=1 ttl=64 time=0.308 ms
64 bytes from 192.168.8.1: icmp_seq=2 ttl=64 time=0.227 ms
64 bytes from 192.168.8.1: icmp_seq=3 ttl=64 time=0.220 ms
^C
--- 192.168.8.1 ping statistics ---
3 packets transmitted, 3 received, 0% packet loss, time 1999ms
rtt min/avg/max/mdev = 0.220/0.251/0.308/0.043 ms

Pinging 8.8.8.8:

nimbus@nimbus-NS150:~$ ping 8.8.8.8
PING 8.8.8.8 (8.8.8.8) 56(84) bytes of data.
^C
--- 8.8.8.8 ping statistics ---
4 packets transmitted, 0 received, 100% packet loss, time 3022ms

tracepath 8.8.8.8

1?: [LOCALHOST]                            pmtu 1500
1: Luxul.lan                                 0.485ms
1: Luxul.lan                                 0.502ms
2: no reply
3: no reply

To sum it up: LAN DNS seems to work fine. DNS settings look correct (as far as I can tell). WAN DNS does not work. However remote desktop software such as Teamviewer is semi-functional.

Thanks for your help, Jeff

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1 Answer 1

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First off all: thanks for a very elaborate question! :-)

Couple additional ones (question/remark):

  • is the switch (where LAN-interface is connected to) connected to the router as well? I ask this because LAN- and WAN-address are in the same "network" 192.168.8.x ? This might create packet-loops (ie. router gets request from LAN-ip for web, wants to return answer through shortest path to host, being WAN-ip, PC doesn't know what to do?)
  • Your "WAN DNS" is working, nslookup works? "WAN Ping" is a different story.

Second, I would do this:

Put WAN-interface on DHCP, edit the router to always hand out the same IP-address to the MAC-address of said WAN-interface.

Put LAN-interface on Static, and DON'T add gateway. That way, all internet-related traffic is forced to WAN-interface.

Regards.

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  • Thanks for the reply! - The switch is connected to the router, it's an unmanaged switch so the whole network is managed by the router. The idea was to have a more robust connection with 2 network ports, but it may be causing these issues :) - Good to know on the DNS. I changed the static to DHCP, I'm hesitant to remove the gateway from the second LAN because I believe that is the port Teamviewer is primarily using (based on upload/download size). I'm going to disconnect one of the ports, if it's a packet feedback issue that should solve it.
    – ubawesomtu
    Aug 19, 2015 at 16:21
  • Unplugging one of the network cables fixed it, so it must have been a packet feedback error! Thank you for your help, I don't have enough rep to vote your answer up but I really appreciate it. Marking this question as solved.
    – ubawesomtu
    Aug 19, 2015 at 16:42
  • A gateway is defined as a portal to a different network than your own (19.2.168.8.x). If you know for a fact that any traffic on the LAN-connection is on the same network, a gateway is not required. Removing the Gateway from LAN-connection would force all traffic for the web over the WAN-connection, including Teamviewer. If it fails, it's pretty easy to put back? :)
    – Anakin
    Aug 20, 2015 at 6:36

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