networking – Need explanation for a public WiFi network

Check out the image here

I came across this network on a public WiFi on a Railway Station. I wanna know the network and the details and most specifically, how I was able to get an IP from the range 100.x.x.x as Private IP ranges are 10.x.x.x, 172.16.x.x-172.31.x.x & 192.168.x.x with subnets of 8, 16 and 24 respectively. I know there is a use of CIDR networking in this case due to which I can find out the number of networks and hosts using operation on individual bits. But how am I able to get an IP from a public IP range is what I’m intertested in knowing. A complete breakdown of the whole network will be highly appreciated. Thanks.

networking – Diagnosing Ubuntu Ethernet Connection

I’m running Ubuntu 18.04.4 LTS, with Cinnamon as desktop environment.

Yesterday my Ethernet connection disconnected and now I can no longer use the Internet; on Chromium the error is DNS_PROBE_FINISHED_NO_INTERNET. However, in my Network Manager, I am still connected to “Wired Connection 1”.

What steps do I take to diagnose where the problem is? Do I need to provide more information? I’m not familiar with networking. I’m currently using a mobile modem as a replacement.


Output of various commands that may be useful:

ifconfig – enp10s0 is the ethernet which is having issues.

enp10s0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet  netmask  broadcast
        inet6 fd80::d95c:db70:d668:7afc  prefixlen 64  scopeid 0x0<global>
        inet6 fd80::2de8:4bea:acf9:bc9a  prefixlen 64  scopeid 0x0<global>
        inet6 fe80::2618:40ca:20d3:6055  prefixlen 64  scopeid 0x20<link>
        ether 70:85:c2:55:07:64  txqueuelen 1000  (Ethernet)
        RX packets 2134  bytes 163311 (163.3 KB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 1895  bytes 168216 (168.2 KB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

lo: flags=73<UP,LOOPBACK,RUNNING>  mtu 65536
        inet  netmask
        inet6 ::1  prefixlen 128  scopeid 0x10<host>
        loop  txqueuelen 1000  (Local Loopback)
        RX packets 2864  bytes 234021 (234.0 KB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 2864  bytes 234021 (234.0 KB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0


Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
default         _gateway         UG    20100  0        0 enp10s0
link-local     U     1000   0        0 enp10s0   U     100    0        0 enp10s0

ping -c4

PING ( 56(84) bytes of data.
From icmp_seq=1 Destination Net Unreachable
From icmp_seq=2 Destination Net Unreachable
From icmp_seq=3 Destination Net Unreachable
From icmp_seq=4 Destination Net Unreachable

--- ping statistics ---
4 packets transmitted, 0 received, +4 errors, 100% packet loss, time 3035ms

sudo ethtool enp10s0

Settings for enp10s0:
    Supported ports: ( TP MII )
    Supported link modes:   10baseT/Half 10baseT/Full 
                            100baseT/Half 100baseT/Full 
                            1000baseT/Half 1000baseT/Full 
    Supported pause frame use: No
    Supports auto-negotiation: Yes
    Supported FEC modes: Not reported
    Advertised link modes:  10baseT/Half 10baseT/Full 
                            100baseT/Half 100baseT/Full 
    Advertised pause frame use: Symmetric Receive-only
    Advertised auto-negotiation: Yes
    Advertised FEC modes: Not reported
    Link partner advertised link modes:  10baseT/Half 10baseT/Full 
                                         100baseT/Half 100baseT/Full 
    Link partner advertised pause frame use: Symmetric
    Link partner advertised auto-negotiation: Yes
    Link partner advertised FEC modes: Not reported
    Speed: 1000Mb/s
    Duplex: Full
    Port: MII
    PHYAD: 0
    Transceiver: internal
    Auto-negotiation: on
    Supports Wake-on: pumbg
    Wake-on: g
    Current message level: 0x00000033 (51)
                   drv probe ifdown ifup
    Link detected: yes

ip route

default via dev enp10s0 proto dhcp metric 20100 dev enp10s0 scope link metric 1000 dev enp10s0 proto kernel scope link src metric 100 

networking – Netgear R6400v2 enable incoming IPv6

I’ve got a Netgear R6400v2 running V1.0.4.98_10.0.71 and have IPv6 enabled on it (and by my ISP). From an external network, I’m able to ping and connect to the router itself, but am unable to connect to any of the devices inside the network. It appears that the router is blocking incoming requests. I am fairly confident it is being blocked by the router as I’ve tried with both MacOS and Windows 10 – both of whom have their firewalls configured to allow external pings. I will further clarify that outgoing IPv6 (and regular browsing, and test-ipv6) work from both computers.

I’ve disabled the routers VPN functionality already (as the configuration interface stated IPv6 doesn’t work with the router’s VPN server enabled).

Where can I configure it to allow incoming requests? It appears as the router is acting as a firewall on IPv6, but I can’t find anywhere to configure its IPv6 port blocking.

networking – Issues connecting to aws ec2 instance behind eip

I have an ec2 instance on which I’m running a dev server via parcel index.html --host that ultimately listens on Before creating and associating an eip to my instance, I wanted to use the public ip address assoc’d with it and modified my iptables via

sudo iptables -t nat -A PREROUTING -i eth0 -p tcp --dport 80 -j REDIRECT --to-port 1234

This allowed me to visit my server via the browser using the public ip address assoc’d with my ec2 instance and receive the response I expect.

However, I’ve now created and assoc’d an eip with my instance (because it’s a dev server and I start and stop the instance regularly, I want a constant ip address) and although I can continue to ssh into my instance via the eip address, I can’t visit the server by using the eip address in my browser.

Since I’m able to ssh to the instance via the eip I wonder if there is some configuration local to the instance that I need to modify to make requests to my server.

Any help is greatly appreciated. Thanks.

networking – isc-dhcp-server host can’t reach the clients

I’ve setup an isc-dhcp-server on an odroid-h2+ on one of the LAN ports, while the other one connected to my main router. I have the dhcp server network port connected to a PoE router with one camera plugged in and my laptop is also plugging in on that side.

I can see that the isc-dhcp-server is leasing IPs fine (i’m using webmin to make management a little easier). From the laptop (on the same subnet), I can reach the web interface of the camera and can view the video stream with issues. When I try to navigate to the camera web interface from the odroid-h2+, which is running the dhcp server, I can’t hit any of the leased IPs, including the camera. Is there additional setup I need to do?

networking – Internet connection error with wine/game maker studio 2

I have installed Ubuntu 20.04 and wine 5.01 and am trying to run game maker studio 2. I was finally able to get the gamemaker software installed but when I try to login to my account, I get an error that the gamemaker program that runs through wine can’t access the internet. Does anyone know any way that I can resolve this and get it to work?

networking – Have access 2 networks but both are still independent

This is my setup:

    *House 1*      :   House 2**
          (C)      :      Device1
         /         :     /
          Devices  :      Device 2
  • (A) – modem router: internet source1 global, also is DHCP server
  • (B) – Router: used as extender (DHCP off)
  • (C) – modem
    router: internet source2 closed, DHCP is off (
  • (D) –
    Router: used as another extender, DHCP is off

What I do to access (C) internet through (D) by setting device gateway( and ip (, and was able to get this to work but couldn’t make it work now

Essentially what I want to achieve is to (D) to only have access to (C) internet but also be able to access a server on network (A). Like access 2 networks via one cable and only House 2 having access to (C)

I have minimal knowledge on networking, and most of the routers in this setup have just basic functionality

networking – Use raspberry pi 3 as network switch?

I own a raspberry pi 3 with integrated wifi and I have several computers I would like to connect with ethernet cables for gigabit file transfers. Unfortunately the home’s router is located on a different level of the house and there is NO chance of getting an ethernet cable from the router downstairs. I own a network switch.

I am wondering if it is possible to connect the switch to the raspberry pi, which is connected to the router wirelessly, and then plug each computer into the switch to transfer files between them at gigabit speeds. Would this work, or is it impossible? If impossible, why?

networking – I am looking for a service that can host PDF files in the local network over HTTP

Problem: In the local network i have touchscreen devices with embedded HTML5 browsers (no other OS. No possibility for FTP to download a file).

I would like to host a bunch of PDF files on one machine, so each of the touchscreen devices could read the PDF files in their browsers.

An example URL would be:

At times there is no internet access, so i don’t want to host them online either.

networking – High ping in emulator

I want to play mlbb on pc android emulator since it does not run on android x86. I have 70~90 ping on my network. But i am getting more than 150 in emulator. I tried switching netork mode and used bluestac and nox. But no difference. Why is my emulator ping high?

Cpu=core i3 6100
Gpu=gtx 1050 ti
ram=4gb(8gb page)