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I use WiFi for connecting to internet using my Ubuntu 18.04.2. It works fine. But, after some random interval of time, the internet connectivity goes down. The WiFi is still on and the device is connected to it(I also verified this by checking the active client list of my router by logging into the router from another device). After the connectivity goes down, I can't even ping my gateway(Router's IP). If I try to ping my router(IP 192.168.0.1), it shows that destination host is unreachable.

So, for troubleshooting the issue, I decided to take a look at my ARP table. After running the arp command, I see the following output:

Address                  HWtype  HWaddress           Flags Mask            Iface
192.168.0.1                      (incomplete)                              wlp13s0

192.168.0.1 is my router's IP address. This is it! the ARP requests are incomplete. This is the problem. But, I want to know exactly why this is happening. I know ARP poisoning is not being performed because, even if I disconnect all other devices and then perform an ARP request after clearing ARP cache, the problem still persists.

Surprisingly, if I turn off the WiFi and then turn it on again, I get my internet access back. This is a "temporary" fix of the issue. After getting my internet access back, if I run ARP request, I get the following response:

Address                  HWtype  HWaddress           Flags Mask            Iface
192.168.0.1              ether   My Router's MAC Addr   C                     wlp13s0

Can someone help me resolving this issue and tell me what next steps should I perform to fix this permanently?

Extra info:

My device uses RTL8723BE for WiFi connectivity and it has a known issue for having poor WiFi reception in Ubuntu. So, I use the rtlwifi_new driver by Larry Finger as suggested in this answer: https://askubuntu.com/a/722904/925252

user3752033
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    Try to remove the out-of tree driver. Support of this adapter is OK in new kernels. The answer you referred to is 2 year old. – Pilot6 Mar 03 '19 at 09:55
  • @Pilot6 If I remove the driver, my laptop receives an extremely poor WiFi signal. Link Quality=28/70 (from iwconfig command). – user3752033 Mar 03 '19 at 10:00
  • Did you use ant_sel parameter to fix antennas? – Pilot6 Mar 03 '19 at 10:00
  • @Pilot6 Yes, I need to set ant_sel=2 but, this thing does not work without this driver. – user3752033 Mar 03 '19 at 10:01
  • It should work. What does modinfo rtl8723be | grep parm show? What is your kernel version? – Pilot6 Mar 03 '19 at 10:06
  • @Pilot6 My kernel version: 4.15.0-45-generic – user3752033 Mar 03 '19 at 10:10
  • Output of modinfo:

    parm: swenc:Set to 1 for software crypto (default 0) parm: ips:Set to 0 to not use link power save (default 1) parm: swlps:Set to 1 to use SW control power save (default 0) parm: fwlps:Set to 1 to use FW control power save (default 1) parm: msi:Set to 1 to use MSI interrupts mode (default 0) parm: debug:Set debug level (0-5) (default 0) (int) parm: disable_watchdog:Set to 1 to disable the watchdog (default 0) parm: ant_sel:Set to 1 or 2 to force antenna number (default 0)

     – user3752033 Mar 03 '19 at 10:11
  • So ant_sel should work. Try 1 and 2 carefully. – Pilot6 Mar 03 '19 at 10:11
  • I tried both 1 and 2 but, it did not work until I installed that driver – user3752033 Mar 03 '19 at 10:12
  • I would first try turning off the power management function. See here. https://askubuntu.com/questions/85214/how-can-i-prevent-iwconfig-power-management-from-being-turned-on (Note: use the one in answer 21.) – kc1di Mar 03 '19 at 11:25
  • @kc1di I tried doing that but, it did not help. And I know that my radio activities are not being blocked in that state because I tried running nmcli and rfkill commands to check the connection status and here is what I got as output:

    Output of nmcli radio :

    WIFI-HW WIFI WWAN-HW WWAN enabled enabled enabled enabled

    and output of rfkill :

    ID TYPE DEVICE SOFT HARD 1 wlan phy0 unblocked unblocked 3 bluetooth hci0 blocked unblocked

     – user3752033 Mar 04 '19 at 16:42

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