Laptop can only access internet on one network

Question

I am experiencing an issue with my laptop where I can only connect to the internet on my home network. I have tried connecting to WiFi networks at work and my school but am unable to connect to the internet. The initial process of establishing a connection appears to work fine, but once connected I am unable to connect to the broader internet. When trying to access a webpage, Google chrome gives a DNS_PROBE_FINISHED_BAD_CONFIG error, while Firefox gives a more generic, "could not access internet". This issue happened once before and I only managed to fix it by reinstalling the OS, something I'm not looking forward to as I just reinstalled my OS (different reason) less then a week ago.

In summary:

Home WiFi - Works
School or Work WiFi - doesn't work
Home Ethernet - Works
Tethering (WiFi hotspot) - doesn't work
Tethering (USB) - doesn't work

System information:

OS: Ubuntu 15.10
Network controller: Intel Corporation Wireless 7260
Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller (rev 10)

Output of ifconfig:

enp2s0    Link encap:Ethernet  HWaddr 1c:b7:2c:5d:f8:b5  
          UP BROADCAST MULTICAST  MTU:1500  Metric:1
          RX packets:550 errors:0 dropped:0 overruns:0 frame:0
          TX packets:482 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:169295 (169.2 KB)  TX bytes:92222 (92.2 KB)

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:198 errors:0 dropped:0 overruns:0 frame:0
          TX packets:198 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0 
          RX bytes:50104 (50.1 KB)  TX bytes:50104 (50.1 KB)

wlp3s0    Link encap:Ethernet  HWaddr 7c:5c:f8:28:7d:7d  
          inet addr:192.168.1.70  Bcast:192.168.1.255  Mask:255.255.255.0
          inet6 addr: 2602:306:37a0:1780:6d45:f56b:b8e3:8875/64 Scope:Global
          inet6 addr: 2602:306:37a0:1780:7e5c:f8ff:fe28:7d7d/64 Scope:Global
          inet6 addr: fe80::7e5c:f8ff:fe28:7d7d/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:16014 errors:0 dropped:0 overruns:0 frame:0
          TX packets:12997 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:13259711 (13.2 MB)  TX bytes:2317858 (2.3 MB)

Is the DHCP Address that you're using at home set by you, or did your router give that to you? — eyoung100, Mar 28 '16 at 20:56
@eyoung100 Nope, I did not do any special configuration on any of these networks. — Robopilot99, Mar 28 '16 at 21:13
@eyoung100 That didn't fix it but I think you're on the right track. It would certainly explain the strange behavior. I'll experiment with the DHCP settings some more tomorrow and see if that doesn't fix the issue. Thank you for the informative and complete post anyways. — Robopilot99, Mar 28 '16 at 23:54

score 1 · Answer 1 · edited Jun 12 '20 at 14:37

Problem

First, I love this handy little comment in my hosts file:

#
# According to RFC 1918, you can use the following IP networks for private
# nets which will never be connected to the Internet:
#
#       10.0.0.0        -   10.255.255.255
#       172.16.0.0      -   172.31.255.255
#       192.168.0.0     -   192.168.255.255
#
# In case you want to be able to connect directly to the Internet (i.e. not
# behind a NAT, ADSL router, etc...), you need real official assigned
# numbers.  Do not try to invent your own network numbers but instead get one
# from your network provider (if any) or from your regional registry (ARIN,
# APNIC, LACNIC, RIPE NCC, or AfriNIC.)

It sounds to me as though your router is handing out a Class C non registered IP Address between 192.168.0.0 and 192.168.255.255, just like the above comment states. The problem here is, your school and any other network you've decided to connect to is also handing out a Class C non registered IP Address between 192.168.0.0 and 192.168.255.255, with the following caveat (In bold):

Solution

The DNS Server stored in your home networks Gateway, usually 192.168.1.1, in your case, is not the DNS Server for all the other networks, stored in their gateway. Since your network at home, and the network at school are using the same RFC rules, your new address is most likely never requested, possibly because you're not disconnecting from your network at home. For example, you can't use your home connection entry for school.

Please use the Following AskUbuntu Question and answer:

How do I remove obsolete Network entries from Network Connection Applet

noting that your connections aren't obsolete, just misconfigured.

After removing them all, recreate the one for your Home, and name it Home, when at home, one for School named School, when at school, and lastly, one at the CoffeShop... you gt the idea. Make sure each one is set to DHCP, with empty DNS Servers, and IPv4 only. Someone will tell you if it's IPv6.

After recreating all your connections, properly use NetworkManager to uncheck Home, and check School etc. Wireless is not automatic.

score 0 · Answer 2 · edited Jun 11 '18 at 13:58

It seems like packages will only be sent through a specific router, since both home ethernet and wifi work (and that's via the same router I suppose). Maybe according to some odd configuration based on the IP or MAC address?

Check out iptables frontend ufw and if the configuration under "network connections"/"cable connection 1"/"IPv4 settings" (sorry for the rough translation) is the same as for the school/work connections

Laptop can only access internet on one network

2 Answers2

Problem

Linked