3

My system is running Ubuntu 16.04 LTS and I have been facing a weird problem ever since I started using it. Many times, when I try to open a website on my browser (Firefox), I'm told "Server Not Found" and only after refreshing the page numerous times I can get to the webpage. This problem does not occur always or for every website simultaneously, but it does happen frequently enough to annoy the hell out of me.

Can anybody shed any light on this?

PS. This issue seems to be unique for 16.04. I use a LAN connection and nobody else using this connection has this problem (none of them are running 16.04 though). Also, I had 12.04 before on the same system and it worked fine.

Edit

tracepath google.com


1?: [LOCALHOST]                                         pmtu 1500
 1:  192.168.0.1                                           0.647ms 
 1:  192.168.0.1                                           0.706ms 
 2:  10.119.246.117                                        1.054ms 
 3:  10.161.18.177                                         9.200ms asymm  7 
 4:  10.255.235.197                                        8.859ms asymm  7 
 5:  10.119.73.122                                         9.298ms 
 6:  no reply
 7:  no reply
 8:  no reply
 9:  no reply
10:  no reply
11:  no reply
12:  no reply
13:  no reply
14:  no reply
15:  no reply
16:  no reply
17:  no reply

and so on.

ping -c 20ping -c 20 google.com
PING google.com (216.58.220.206) 56(84) bytes of data.
64 bytes from del01s08-in-f14.1e100.net (216.58.220.206): icmp_seq=1 ttl=56 time=45.3 ms
64 bytes from del01s08-in-f14.1e100.net (216.58.220.206): icmp_seq=2 ttl=56 time=45.4 ms
64 bytes from del01s08-in-f14.1e100.net (216.58.220.206): icmp_seq=3 ttl=56 time=46.1 ms
64 bytes from del01s08-in-f14.1e100.net (216.58.220.206): icmp_seq=4 ttl=56 time=45.3 ms
64 bytes from del01s08-in-f14.1e100.net (216.58.220.206): icmp_seq=5 ttl=56 time=45.3 ms
64 bytes from del01s08-in-f14.1e100.net (216.58.220.206): icmp_seq=6 ttl=56 time=45.3 ms
64 bytes from del01s08-in-f14.1e100.net (216.58.220.206): icmp_seq=7 ttl=56 time=45.4 ms
64 bytes from del01s08-in-f14.1e100.net (216.58.220.206): icmp_seq=8 ttl=56 time=45.5 ms
64 bytes from del01s08-in-f14.1e100.net (216.58.220.206): icmp_seq=9 ttl=56 time=45.3 ms
64 bytes from del01s08-in-f14.1e100.net (216.58.220.206): icmp_seq=10 ttl=56 time=45.6 ms
64 bytes from del01s08-in-f14.1e100.net (216.58.220.206): icmp_seq=11 ttl=56 time=45.3 ms
64 bytes from del01s08-in-f14.1e100.net (216.58.220.206): icmp_seq=12 ttl=56 time=45.6 ms
64 bytes from del01s08-in-f14.1e100.net (216.58.220.206): icmp_seq=13 ttl=56 time=45.7 ms
64 bytes from del01s08-in-f14.1e100.net (216.58.220.206): icmp_seq=14 ttl=56 time=45.5 ms
64 bytes from del01s08-in-f14.1e100.net (216.58.220.206): icmp_seq=15 ttl=56 time=45.3 ms
64 bytes from del01s08-in-f14.1e100.net (216.58.220.206): icmp_seq=16 ttl=56 time=45.3 ms
64 bytes from del01s08-in-f14.1e100.net (216.58.220.206): icmp_seq=17 ttl=56 time=45.3 ms
64 bytes from del01s08-in-f14.1e100.net (216.58.220.206): icmp_seq=18 ttl=56 time=45.3 ms
64 bytes from del01s08-in-f14.1e100.net (216.58.220.206): icmp_seq=19 ttl=56 time=45.2 ms
64 bytes from del01s08-in-f14.1e100.net (216.58.220.206): icmp_seq=20 ttl=56 time=45.3 ms

--- google.com ping statistics ---
20 packets transmitted, 20 received, 0% packet loss, time 19027ms
rtt min/avg/max/mdev = 45.289/45.459/46.109/0.307 ms

Also this

 cat /etc/nsswitch.conf
# /etc/nsswitch.conf
#
# Example configuration of GNU Name Service Switch functionality.
# If you have the `glibc-doc-reference' and `info' packages installed, try:
# `info libc "Name Service Switch"' for information about this file.

passwd:         compat
group:          compat
shadow:         compat
gshadow:        files

hosts:          files mdns4_minimal [NOTFOUND=return] dns
networks:       files

protocols:      db files
services:       db files
ethers:         db files
rpc:            db files

netgroup:       nis

and this

computer                  
    description: Desktop Computer
    product: P6-2356IN (H3W39AA#ACJ)
    vendor: Hewlett-Packard
    serial: [REMOVED]
    width: 64 bits
    capabilities: smbios-2.7 dmi-2.7 vsyscall32
    configuration: boot=normal chassis=desktop family=103C_53316J G=D sku=H3W39AA#ACJ uuid=[REMOVED]
  *-core
       description: Motherboard
       product: 2ABF
       vendor: Foxconn
       physical id: 0
       version: 3.10
     *-firmware
          description: BIOS
          vendor: AMI
          physical id: 0
          version: 8.12
          date: 12/14/2012
          size: 64KiB
          capacity: 8128KiB
          capabilities: pci pnp upgrade shadowing cdboot bootselect edd int5printscreen int9keyboard int14serial int17printer acpi usb biosbootspecification netboot uefi
     *-cache:0
          description: L2 cache
          physical id: 23
          slot: CPU Internal L2
          size: 1MiB
          capacity: 1MiB
          capabilities: internal write-through unified
          configuration: level=2
     *-cache:1
          description: L1 cache
          physical id: 24
          slot: CPU Internal L1
          size: 256KiB
          capacity: 256KiB
          capabilities: internal write-through data
          configuration: level=1
     *-cache:2
          description: L3 cache
          physical id: 25
          slot: CPU Internal L3
          size: 6MiB
          capacity: 6MiB
          capabilities: internal write-back unified
          configuration: level=3
     *-cpu
          description: CPU
          product: Intel(R) Core(TM) i5-3330 CPU @ 3.00GHz
          vendor: Intel Corp.
          physical id: 27
          bus info: cpu@0
          version: Intel(R) Core(TM) i5-3330 CPU @ 3.00GHz
          slot: SOCKET 0
          size: 1707MHz
          capacity: 3800MHz
          width: 64 bits
          clock: 100MHz
          capabilities: x86-64 fpu fpu_exception wp vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx rdtscp constant_tsc arch_perfmon pebs bts rep_good nopl xtopology nonstop_tsc aperfmperf eagerfpu pni pclmulqdq dtes64 monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr pdcm pcid sse4_1 sse4_2 x2apic popcnt tsc_deadline_timer aes xsave avx f16c rdrand lahf_lm epb tpr_shadow vnmi flexpriority ept vpid fsgsbase smep erms xsaveopt dtherm ida arat pln pts cpufreq
          configuration: cores=4 enabledcores=4 threads=4
     *-memory
          description: System Memory
          physical id: 28
          slot: System board or motherboard
          size: 4GiB
        *-bank:0
             description: DIMM [empty]
             product: [Empty]
             vendor: [Empty]
             physical id: 0
             serial: [REMOVED]
             slot: DIMM1
        *-bank:1
             description: DIMM DDR3 Synchronous 1600 MHz (0.6 ns)
             product: RMR5040ED58E9W1600
             vendor: Ramaxel
             physical id: 1
             serial: [REMOVED]
             slot: DIMM3
             size: 4GiB
             width: 64 bits
             clock: 1600MHz (0.6ns)
     *-pci
          description: Host bridge
          product: Xeon E3-1200 v2/3rd Gen Core processor DRAM Controller
          vendor: Intel Corporation
          physical id: 100
          bus info: pci@0000:00:00.0
          version: 09
          width: 32 bits
          clock: 33MHz
          configuration: driver=ivb_uncore
          resources: irq:0
        *-pci:0
             description: PCI bridge
             product: Xeon E3-1200 v2/3rd Gen Core processor PCI Express Root Port
             vendor: Intel Corporation
             physical id: 1
             bus info: pci@0000:00:01.0
             version: 09
             width: 32 bits
             clock: 33MHz
             capabilities: pci pm msi pciexpress normal_decode bus_master cap_list
             configuration: driver=pcieport
             resources: irq:25 ioport:e000(size=4096) memory:f6000000-f70fffff ioport:e8000000(size=167772160)
           *-display
                description: VGA compatible controller
                product: GF119 [GeForce GT 620 OEM]
                vendor: NVIDIA Corporation
                physical id: 0
                bus info: pci@0000:01:00.0
                version: a1
                width: 64 bits
                clock: 33MHz
                capabilities: pm msi pciexpress vga_controller bus_master cap_list rom
                configuration: driver=nouveau latency=0
                resources: irq:28 memory:f6000000-f6ffffff memory:e8000000-efffffff memory:f0000000-f1ffffff ioport:e000(size=128) memory:f7000000-f707ffff
           *-multimedia
                description: Audio device
                product: GF119 HDMI Audio Controller
                vendor: NVIDIA Corporation
                physical id: 0.1
                bus info: pci@0000:01:00.1
                version: a1
                width: 32 bits
                clock: 33MHz
                capabilities: pm msi pciexpress bus_master cap_list
                configuration: driver=snd_hda_intel latency=0
                resources: irq:17 memory:f7080000-f7083fff
        *-communication
             description: Communication controller
             product: 6 Series/C200 Series Chipset Family MEI Controller #1
             vendor: Intel Corporation
             physical id: 16
             bus info: pci@0000:00:16.0
             version: 04
             width: 64 bits
             clock: 33MHz
             capabilities: pm msi bus_master cap_list
             configuration: driver=mei_me latency=0
             resources: irq:29 memory:f730a000-f730a00f
        *-usb:0
             description: USB controller
             product: 6 Series/C200 Series Chipset Family USB Enhanced Host Controller #2
             vendor: Intel Corporation
             physical id: 1a
             bus info: pci@0000:00:1a.0
             version: 05
             width: 32 bits
             clock: 33MHz
             capabilities: pm debug ehci bus_master cap_list
             configuration: driver=ehci-pci latency=0
             resources: irq:16 memory:f7308000-f73083ff
           *-usbhost
                product: EHCI Host Controller
                vendor: Linux 4.4.0-47-generic ehci_hcd
                physical id: 1
                bus info: usb@1
                logical name: usb1
                version: 4.04
                capabilities: usb-2.00
                configuration: driver=hub slots=2 speed=480Mbit/s
              *-usb
                   description: USB hub
                   product: Integrated Rate Matching Hub
                   vendor: Intel Corp.
                   physical id: 1
                   bus info: usb@1:1
                   version: 0.00
                   capabilities: usb-2.00
                   configuration: driver=hub slots=4 speed=480Mbit/s
                 *-usb
                      description: Keyboard
                      product: USB Receiver
                      vendor: Logitech
                      physical id: 1
                      bus info: usb@1:1.1
                      version: 29.00
                      capabilities: usb-2.00
                      configuration: driver=usbhid maxpower=98mA speed=12Mbit/s
        *-multimedia
             description: Audio device
             product: 6 Series/C200 Series Chipset Family High Definition Audio Controller
             vendor: Intel Corporation
             physical id: 1b
             bus info: pci@0000:00:1b.0
             version: 05
             width: 64 bits
             clock: 33MHz
             capabilities: pm msi pciexpress bus_master cap_list
             configuration: driver=snd_hda_intel latency=0
             resources: irq:30 memory:f7300000-f7303fff
        *-pci:1
             description: PCI bridge
             product: 6 Series/C200 Series Chipset Family PCI Express Root Port 1
             vendor: Intel Corporation
             physical id: 1c
             bus info: pci@0000:00:1c.0
             version: b5
             width: 32 bits
             clock: 33MHz
             capabilities: pci pciexpress msi pm normal_decode bus_master cap_list
             configuration: driver=pcieport
             resources: irq:16
        *-pci:2
             description: PCI bridge
             product: 6 Series/C200 Series Chipset Family PCI Express Root Port 2
             vendor: Intel Corporation
             physical id: 1c.1
             bus info: pci@0000:00:1c.1
             version: b5
             width: 32 bits
             clock: 33MHz
             capabilities: pci pciexpress msi pm normal_decode bus_master cap_list
             configuration: driver=pcieport
             resources: irq:17 memory:f7200000-f72fffff
           *-network DISABLED
                description: Wireless interface
                product: RT5390R 802.11bgn PCIe Wireless Network Adapter
                vendor: Ralink corp.
                physical id: 0
                bus info: pci@0000:03:00.0
                logical name: wlp3s0
                version: 00
                serial: [REMOVED]
                width: 32 bits
                clock: 33MHz
                capabilities: pm msi pciexpress bus_master cap_list ethernet physical wireless
                configuration: broadcast=yes driver=rt2800pci driverversion=4.4.0-47-generic firmware=N/A latency=0 link=no multicast=yes wireless=IEEE 802.11bgn
                resources: irq:17 memory:f7200000-f720ffff
        *-pci:3
             description: PCI bridge
             product: 6 Series/C200 Series Chipset Family PCI Express Root Port 6
             vendor: Intel Corporation
             physical id: 1c.5
             bus info: pci@0000:00:1c.5
             version: b5
             width: 32 bits
             clock: 33MHz
             capabilities: pci pciexpress msi pm normal_decode bus_master cap_list
             configuration: driver=pcieport
             resources: irq:17 ioport:d000(size=4096) memory:f7100000-f71fffff
           *-network
                description: Ethernet interface
                product: RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller
                vendor: Realtek Semiconductor Co., Ltd.
                physical id: 0
                bus info: pci@0000:04:00.0
                logical name: enp4s0
                version: 06
                serial: [REMOVED]
                size: 100Mbit/s
                capacity: 1Gbit/s
                width: 64 bits
                clock: 33MHz
                capabilities: pm msi pciexpress msix vpd bus_master cap_list ethernet physical tp mii 10bt 10bt-fd 100bt 100bt-fd 1000bt 1000bt-fd autonegotiation
                configuration: autonegotiation=on broadcast=yes driver=r8169 driverversion=2.3LK-NAPI duplex=full firmware=rtl_nic/rtl8168e-2.fw ip=[REMOVED] latency=0 link=yes multicast=yes port=MII speed=100Mbit/s
                resources: irq:26 ioport:d000(size=256) memory:f7104000-f7104fff memory:f7100000-f7103fff
        *-usb:1
             description: USB controller
             product: 6 Series/C200 Series Chipset Family USB Enhanced Host Controller #1
             vendor: Intel Corporation
             physical id: 1d
             bus info: pci@0000:00:1d.0
             version: 05
             width: 32 bits
             clock: 33MHz
             capabilities: pm debug ehci bus_master cap_list
             configuration: driver=ehci-pci latency=0
             resources: irq:23 memory:f7307000-f73073ff
           *-usbhost
                product: EHCI Host Controller
                vendor: Linux 4.4.0-47-generic ehci_hcd
                physical id: 1
                bus info: usb@2
                logical name: usb2
                version: 4.04
                capabilities: usb-2.00
                configuration: driver=hub slots=2 speed=480Mbit/s
              *-usb
                   description: USB hub
                   product: Integrated Rate Matching Hub
                   vendor: Intel Corp.
                   physical id: 1
                   bus info: usb@2:1
                   version: 0.00
                   capabilities: usb-2.00
                   configuration: driver=hub slots=6 speed=480Mbit/s
                 *-usb:0
                      description: Generic USB device
                      product: SLP
                      vendor: SAMSUNG
                      physical id: 4
                      bus info: usb@2:1.4
                      version: 4.00
                      serial: [REMOVED]
                      capabilities: usb-2.00
                      configuration: driver=usbfs maxpower=48mA speed=480Mbit/s
                 *-usb:1
                      description: Mass storage device
                      product: Mass Storage Device
                      vendor: Generic
                      physical id: 6
                      bus info: usb@2:1.6
                      logical name: scsi5
                      version: 1.00
                      serial: [REMOVED]
                      capabilities: usb-2.00 scsi emulated scsi-host
                      configuration: driver=usb-storage maxpower=100mA speed=480Mbit/s
                    *-disk
                         description: SCSI Disk
                         physical id: 0.0.0
                         bus info: scsi@5:0.0.0
                         logical name: /dev/sdb
                         configuration: logicalsectorsize=512 sectorsize=512
        *-isa
             description: ISA bridge
             product: H61 Express Chipset Family LPC Controller
             vendor: Intel Corporation
             physical id: 1f
             bus info: pci@0000:00:1f.0
             version: 05
             width: 32 bits
             clock: 33MHz
             capabilities: isa bus_master cap_list
             configuration: driver=lpc_ich latency=0
             resources: irq:0
        *-storage
             description: SATA controller
             product: 6 Series/C200 Series Chipset Family SATA AHCI Controller
             vendor: Intel Corporation
             physical id: 1f.2
             bus info: pci@0000:00:1f.2
             version: 05
             width: 32 bits
             clock: 66MHz
             capabilities: storage msi pm ahci_1.0 bus_master cap_list
             configuration: driver=ahci latency=0
             resources: irq:27 ioport:f070(size=8) ioport:f060(size=4) ioport:f050(size=8) ioport:f040(size=4) ioport:f020(size=32) memory:f7306000-f73067ff
        *-serial UNCLAIMED
             description: SMBus
             product: 6 Series/C200 Series Chipset Family SMBus Controller
             vendor: Intel Corporation
             physical id: 1f.3
             bus info: pci@0000:00:1f.3
             version: 05
             width: 64 bits
             clock: 33MHz
             configuration: latency=0
             resources: memory:f7305000-f73050ff ioport:f000(size=32)
     *-scsi:0
          physical id: 1
          logical name: scsi1
          capabilities: emulated
        *-disk
             description: ATA Disk
             product: ST3500414CS
             vendor: Seagate
             physical id: 0.0.0
             bus info: scsi@1:0.0.0
             logical name: /dev/sda
             version: CA14
             serial: [REMOVED]
             size: 465GiB (500GB)
             capabilities: gpt-1.00 partitioned partitioned:gpt
             configuration: ansiversion=5 guid=f83e4e9e-ebeb-4ea7-b272-14a761ba61bd logicalsectorsize=512 sectorsize=512
           *-volume:0 UNCLAIMED
                description: Windows FAT volume
                vendor: mkfs.fat
                physical id: 1
                bus info: scsi@1:0.0.0,1
                version: FAT32
                serial: [REMOVED]
                size: 510MiB
                capacity: 511MiB
                capabilities: boot fat initialized
                configuration: FATs=2 filesystem=fat name=EFI System Partition
           *-volume:1
                description: EXT4 volume
                vendor: Linux
                physical id: 2
                bus info: scsi@1:0.0.0,2
                logical name: /dev/sda2
                logical name: /
                version: 1.0
                serial: [REMOVED]
                size: 461GiB
                capabilities: journaled extended_attributes large_files huge_files dir_nlink recover extents ext4 ext2 initialized
                configuration: created=2016-09-08 18:49:43 filesystem=ext4 lastmountpoint=/ modified=2016-11-19 08:19:23 mount.fstype=ext4 mount.options=rw,relatime,errors=remount-ro,data=ordered mounted=2016-11-19 08:19:29 state=mounted
           *-volume:2
                description: Linux swap volume
                vendor: Linux
                physical id: 3
                bus info: scsi@1:0.0.0,3
                logical name: /dev/sda3
                version: 1
                serial: [REMOVED]
                size: 4052MiB
                capacity: 4052MiB
                capabilities: nofs swap initialized
                configuration: filesystem=swap pagesize=4095
     *-scsi:1
          physical id: 2
          logical name: scsi4
          capabilities: emulated
        *-cdrom
             description: DVD-RAM writer
             product: DVD A  DH16ACSHR
             vendor: hp
             physical id: 0.0.0
             bus info: scsi@4:0.0.0
             logical name: /dev/cdrom
             logical name: /dev/cdrw
             logical name: /dev/dvd
             logical name: /dev/dvdrw
             logical name: /dev/sr0
             version: JHG6
             capabilities: removable audio cd-r cd-rw dvd dvd-r dvd-ram
             configuration: ansiversion=5 status=nodisc
  *-power UNCLAIMED
       product: Standard Efficiency
       physical id: 1
       capacity: 32768mWh
Improve this question
9
  • 1
    Does your ISP have IPv6 enabled by any chance? Who is your ISP?
    – Ken Sharp
    Nov 16, 2016 at 4:04
  • 1
    @KenSharp My internet access is provided by my university, which probably is also my ISP. As for whether IPv6 is enabled, I really cannot say for sure. But test-ipv6.com tells me that "No IPv6 address detected".
    – Sayantan
    Nov 16, 2016 at 5:45
  • 1
    What about any other browser?
    – kcpr
    Nov 19, 2016 at 13:03
  • 1
    @kcpr I tried with Chromium. Same thing.
    – Sayantan
    Nov 20, 2016 at 2:40
  • 2
    @Sayantan, Could you add some debuging info: ping -c 20 google.com , tracepath google.com , cat /etc/nsswitch.conf , ifconfig , route , iwconfig, sudo lshw -sanitize
    – user.dz
    Nov 20, 2016 at 23:44

2 Answers 2

Reset to default
0

Check first your Network Manager. whether your IPv6 is enable or not doesn't give much attention but when when your IPv4 is in a static then you'll get a problem. Make sure your IPv4 is on a obtain mode for dynamic IP address. then just like windows disable and enable it for a few seconds,to refresh.Then open again your browser.

Improve this answer
0

You are probably experiencing a DNS problem, mostly caused by slow local DNS servers. You can find out your current DNS setting by invoking:

nmcli dev show | grep DNS

Try setting your DNS to something like 4.2.2.4.

For a better diagnosis, do the steps listed here:

Server Not Found - Troubleshoot connection problems

https://support.mozilla.org/en-US/kb/server-not-found-connection-problem

You should test other browsers, and upon the result you can find out exactly the root of problem. But according to what you have stated, the highest possiblity is the DNS problem. This can be remedied with DNS prefetching, although it has some drawbacks.

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