I use Ubuntu 16.04 and connect my machine alongside other machines by using a switch to a modem to use Internet. Today I encountered a problem:
Other machines can connect to the Internet; but I cannot access the web (Server Not Found error on browser and
ping: unknown host google.com as result of
$ ping google.com in terminal), except after doing disconnecting/re-connecting network cable. But this way only works for a short time, a few seconds up to 2 minutes. Meanwhile, my Android device can connect to the web continuously without any problem through WiFi.
I tried connecting my machine directly to the modem and even changed the network (Ethernet) cable. But result was the same.
What causes this problem and how I can solve it?
I can open 192.168.1.1 from my machine but cannot login; although it is possible to do that from my other machines.
I checked my connection and
/var/log/syslog. It seems that my machine automatically changes used connection from
Internet (which is used to access web) to
virbr0 which causes problem:
When I can access web:
When problem occurs:
virbr0 must be created and used by VirtualBox. I use VirtualBox 5.1.38.
Also sometimes I can access the web without any problem from my guest OS, during time that I cannot do that from host! But I created guests along time ago, for example 2 or 3 monthes ago, and this problem occurred only this week.
nslookup askubuntu.com when I can access the web:
$ nslookup askubuntu.com Server: 127.0.1.1 Address: 127.0.1.1#53 Non-authoritative answer: Name: askubuntu.com Address: 18.104.22.168 Name: askubuntu.com Address: 22.214.171.124 Name: askubuntu.com Address: 126.96.36.199 Name: askubuntu.com Address: 188.8.131.52
I did these; but problem remains:
- using another modem
- replacing network cable with another
Also I tethered my machine to an Android device and could access the web without any problem.
I could connect to Internet in
guest session without any problem, so it seems that problem only occurs on my current account and I'm sure
NIC does not cause this problem.