Edit: "I cannot access few websites and portal"
If you are not able to access some websites, there may be an ACL on these networks (such as a public IP limitation), or you could have routing issues to the subnets in which they resolve.
For example, if you can't reach mytest.portal.business.com
and it resolves as 10.1.1.3
, then this would stipulate it's an internally hosted service that you've got a static record for. If a large portion of websites work (such as YouTube, Google, AskUbuntu) but a subset don't, this would indicate more of an issue with networking/routing than the system in itself.
If you're able to successfully resolve (via nslookup
) and test an ICMP connection (ping
) then this denotes you have network connectivity; if you perform sudo apt upgrade -y
and it functions, you have networking connectivity and this brings the issue down to an application fault.
In this instance, it appears that you're in fact using WiFi as your connection medium, as denoted by your ip a
which resulted in:
wlp3s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
link/ether 5c:e0:c5:3a:7d:0c brd ff:ff:ff:ff:ff:ff
inet 192.168.0.107/24 brd 192.168.0.255 scope global dynamic noprefixroute wlp3s0
valid_lft 85831sec preferred_lft 85831sec
inet6 fe80::f9d:3b03:c8d4:43e3/64 scope link noprefixroute
valid_lft forever preferred_lft forever
DHCP
First and foremost, I would confirm that you're getting DHCP on the same logical subnet as other clients that are working - this is simple, compare ip a
on hosts to ensure you're in the same range. For example, this could be 192.168.0.1
or 172.20.20.1
but (usually) neither together.
To view your DHCP configuration (if you're using netplan
) you can run ls -l /var/lib/NetworkManager
, and what is most important is cat
your lease file - for me:
cat /var/lib/NetworkManager/internal-16fa33b0-caa7-3219-a480-331e166fd77c-eno2.lease
# This is private data. Do not parse.
ADDRESS=192.168.0.116
NETMASK=255.255.255.0
ROUTER=192.168.0.1
SERVER_ADDRESS=192.168.0.1
T1=42600
T2=74550
LIFETIME=85200
DNS=208.67.222.222 208.67.220.220
DOMAINNAME=loopback.local
CLIENTID=01b42e9933fa61
Make sure in the DHCP lease, your router IP address is your local router - and not another IP address you cannot route to without a VPN connection (additional adapter).
DNS
The first test is to ensure your DNS is not the fault, run resolvectl status | grep "DNS Servers"
to list the current server you're using; you can update this to be
something such as 1.1.1.1
as a test:
# See man:systemd-resolved.service(8) for details about the supported modes of
# operation for /etc/resolv.conf.
nameserver 1.1.1.1
Proxy Server
At this point in time, if you're not able to resolve websites (well, load), move on to diagnosing if your system is using a proxy: env | grep proxy
- if you're using a proxy, it'll return an answer. You can find more answers on diagnosing proxies here.
Firewalls
On Ubuntu, you can disable the Firewall temporarily to see if this is contributing. For firewalld
the command is:
systemctl stop firewalld # Disables the Firewall
systemctl status firewalld # Gets the firewall's status
For ufw
, perform the following:
sudo ufw status verbose # Gets the firewall's status
sudo ufw disable # Disables the Firewall
You could further diagnose this by performing a netstat
or a Wireshark capture, if you believed this a networking issue.
Application Diagnostics
From this point, if your browser still doesn't want to load, load an additional browser such as Vivaldi, and see if the same issue occurs. You can run the application via the terminal to get output - or using inbuilt console.
Lastly - as I had this happen to me once - I had a strange "profile" issue with my wireless network. I had to remove the network and reconnect/establish to get it working.
Best Answer
I'd suggest trying another browser.
I get full Flash and Java functionality in SeaMonkey (Firefox engine, skinned to look and act like the old Netscape Navigator Suite, including integrated e-mail and IRC chat clients as well as HTML editor), using
update-sun-jre
andpepperflashplugin
(the latter uses the Chrome Pepper Flash plugin wrapped to match the API the Firefox core expects). Both plugins are as up to date as they can be, and update automatically through the standard Ubuntu software update process (though at least one requires enabling an additional repository -- which itself is considered a security risk).Unfortunately, if you're an "open software" purist, both of these plugins use proprietary code -- but they're what works, at least for me.