Steps that I could take to troubleshoot a network connection for a desktop (no wifi) - networking

This is my first post, so don't judge if I mess something up.
The problem is that I bought a new Desktop PC for my office (a Windows 8 machine with motherboard Z97-HD3 (has integrated Ethernet/LAN card)) and it worked OK for a few weeks, but now, the internet is gone.
When I boot up my PC I get "Network Identifying". After a minute or so, it says that it is connected, but when I open a browser it either says: "This webpage is not available" (more often) or "SSL certificate problem" (rarely). I've been chipping on this problem for a few days and the only steps that I've mustered up to take are these:
1. Is it the cable? Try the Ethernet/LAN cable on a different computer
Tried that. It works on my other laptop. So I conclude that the problem is with the new computer.
2. Is it a software problem or hardware?
2.1. Look at the back of the PC. The Ethernet card lights are on.
2.2. Try pinging localhost. Start > Open command prompt (cmd) > "ping 127.0.0.1". All 4 packages are sent and received with time 1ms
2.3. Maybe there is something wrong with Windows? Tried installing Ubuntu, but the internet doesn't connect as well
Anything else I could do? Or should I conclude that this is a hardware issue and return it to the shop?

First, make sure that you can ping your Gateway (gateways are computers/routers that are between two networks ). You can find out the IP of your gateway by running this in cmd:
ipconfig
There you will see your currently assigned(or static) ipaddress, the subnetwork, as well as the IP of your Gateway. Then try to ping your Gateway.
If you can then you know that all is good with cables and software and the problem is either configuration(you dont have gateway set) or the gateway can't make the connection outside of your local network.
if you can't ping your gateway, then you know something is wrong on your PC.

Related

ESP8266-05 always return +CWJAP:4 on connection to any Wi-Fi network

I am a novice with ESP8266. I have an ESP-05 module connected to my PC USB through CH340 com-port adapter.
I was able to list all networks with AT+CWLAP, but when I put the command to connect to, it shows me a CWJAP:4 error. I tried my home network, the network in my office, and the Wi-Fi network created by my Android phone. The same result always...
AT+GMRAT version:1.3.0.0(Jul 14 2016 18:54:01)
SDK version:2.0.0(5a875ba)
v1.0.0.3
Mar 13 2018 09:35:47
OK
AT+CWMODE=1
OK
AT+CWLAP+CWLAP:(3,"TheSecretChamber",-76,"f0:79:59:d3:00:44",13,68,0)
+CWLAP:(4,"Ufanet_70",-90,"04:5e:a4:76:0d:cf",3,50,0)
+CWLAP:(3,"AndroidAP",-49,"84:98:66:ce:a6:ed",6,66,0)
OK
AT+CWJAP="TheSecretChamber","mypasswordhere"+CWJAP:4
FAIL
The password is 100% valid (I've tried to put the wrong password, in this case, it returns CWJAP:3 as required).
What can be a reason?? Thanks.
I found the solution by myself. It looks like the USB port I used initially has not enough power or it's broken somehow. The network list command is working, but its USB power was not enough to handle transmitting.
I just tried another USB port and it works well.
Thanks all.

Can't access device through network

I'm trying to interface a device with python.
The device is connected to another machine in the same network (the university network) and I know it's Port number.
I can access the device from the PC where it is plugged with the following code:
dev = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
dev.connect(('137.195.53.140',51019))
where '137.195.53.140' is the PC ip, and 51019 is the port number.
However, if I try the same from another machine, ipython gets stack at the command "dev.connect(('137.195.53.140',51019))", and when I abort the evaluation and then look at "dev" I get this:
<socket.socket fd=15, family=AddressFamily.AF_INET, type=SocketKind.SOCK_STREAM, proto=0, laddr=('137.195.204.85', 50393)>
where '137.195.204.85' is the IP of the machine I'm using, and the port number I've no idea.
Since ssh works with no problem within this network, I thought that my approach for accessing the device would have worked as well.
Does anyone have any clue for this? I'm sorry if I haven't been clear, but I know absolutely nothing of networking (and not very much of Python either tbh).
There's couple of things to consider:
Your university network ports
Your device's opened ports
Your network might have the 51019 port blocked. Also, ssh uses port 22 to make it's connection. Every port is a world, so there's the chance that just because 22 is open, it doesn't mean that another is. School networks usually have a pretty rigid policy on port closing for security and blocking unwanted sites too.
You can test your device access by pinging it as
$ ping 137.195.204.85
If that works, then you can go trying different ports

What is causing putty to not connect to beaglebone black

I have a Beaglebone Black(rev c),I am trying to connect it to Windows 8 laptop using putty. I am putting IP address as 192.168.7.2 and port as 22,but when I says open to it,putty window will pop-up and after sometime I will get fatal ERROR saying:
"Network connection time-out"
I am new to this, can someone tell me what am i missing?
Seems to indicate the an SSH server is not running on the BBB. Or possibly for some reason the BBB did not take 192.168.7.2 as an IP. Or perhaps you might need to wait a little bit longer for the SSH server to start up.
Short of this, there is not much to go on. One way to trouble shoot the issue would be to get a serial debug cable, connected and working to the BBB. Then you could dmesg | grep ssh or some such and hopefully get closer to what the actual problem is. Sorry if this is not enough for you to go by, but it is really hard to figure out what is going on without more information.
Other potential problems could be as simple as a USB cable that sometimes works or sometimes doesn't.
It may not be this but have you installed the drivers? See step 2 here: http://beagleboard.org/getting-started. If it's not that or you have already installed those then I am not sure sorry. Perhaps someone else has another suggestion.
Is the BeagleBone connected to your network with an Ethernet cable? It will only use 192.168.7.2 for the network-over-usb when there's only a USB cable connected - if you have Ethernet connected it will use DHCP to get an IP from your router, in which case you can check your router page to see what IP it got.
If you do just have USB connected then a driver issue is the most likely culprit, but you could try to ssh to the hostname beaglebone.local instead of the IP.

Is there a way to detect the number of connections active on a Wifi network?

If I want to detect the number of connections active on my home Wifi network, how should I go ahead doing it? This can be useful for building applications which would serve as monitoring unidentified/unrecognized people being fraudulently misusing a person's Wifi network.
How to know whether your neighbors or others are using your wireless network is rather complicated.
If your neighbors are experienced Wi-Fi hackers, you might not be able to tell at all.
If they're just stealing your Internet connection, you may be able to tell from the logs on your router.
To find out who's on your wireless network, you'll need to start by taking inventory of all the devices that are meant to be connected. Find out their MAC IDs and their IP addresses (if they're static).
To find out the MAC ID/IP address on a PC, click the Start menu and choose Run. Type cmd and click OK. In the screen that opens, type ipconfig /all and hit Enter. The MAC address will be shown as the physical address. Once you know the MAC addresses of each of the PCs on your network, you will recognize any addresses that don’t belong under the screen that shows the MAC addresses of current connections.
Check IP addresses
Likewise you may be able to see how many IP addresses have been dished out by the DHCP server. If you check the IP addresses of each of your PCs, you can see if other IP addresses have been served.
To find out your IP address from the Start menu, click Run. Then type in cmd and click OK. In the screen that comes up, type ipconfig which will display the IP address for that computer. (Bear in mind, however, that if the PC is set to auto detect settings, then the PC's IP address will change the next time the computer is rebooted or switched on. Sometimes previously served numbers have not yet expired, so you may think someone is connected when they are not.)
Dealing with intruders
If you do find someone using your connection, they may well not be doing so maliciously or even knowingly. Sometimes people can’t tell which is their own connection and they may honestly believe that they are using their Wi-Fi router rather than yours. The best way to deal with this is to set up your own security and maybe you can help them find their own router!
The optimal solution is to set up a strong password using WPA or WPA 2 of almost 20 to 30 digits and numbers. Once your network is functioning, you can switch off the SSID broadcast (which prevents it from advertising the name of your network) so it would effectively disappear as far as your neighbors are concerned, and the first you might hear of it is when someone complains that their Web connection has disappeared.
You could look for logs such as current LAN clients, connection or status log, or connected MAC addresses.
Be Happy :-)
Do you have access to the Access Point management ?
Look for MAC addresses and their filtering. Modern APs allow you to filter devices and or limit the timeframe during which devices can authenticate themselves, using a hardware button.
A link on how to secure your AP here, and a good start to know what to play with !
You can Either USE this Command... On your Router or Modem... Some Modem's have console for Ping and Commands like that....
ipconfig -all

Raspberry Pi gets a 192.168.x.x address, but rest of my home network is 10.21.179.x

There is a lot of history here, so please bear with me.
Our home network used to be fine when we were with Comcast, but we wanted better speed and reliability, so we switched to FIOS. At that point, the Wifi connections from my Raspberry Pis stopped working. I got frustrated after a couple of weeks of trying to discover the cause of the problem and eventually put it aside.
The other day, I started to configure a new Raspberry Pi 4 that I plan to use on my new Sphero RVR. I set it up following the usual directions and the Pi connects to the Internet without problem over WiFi, but I can't ping it from my Windows 10 desktop.
So I started digging. I downloaded the Fing app onto my Pixel 3 Android phone and looked at the network. I immediately noticed that all the devices now have a 10.29.179.xxx addresses. That easily explains why I can't ping from my PC to the Raspberry Pi. They aren't in the same address space.
I did discover that I can ping the Raspberry Pi if I use the IPV6 address. I can even get PuTTY to connect using the IPv6 address, although I was unable to successfully login. I don't know what is causing the login problem, but it's probably something mundane.
I suspect that I can make my Rpi conform to the rest of the network using a static IP address, but that might cause problems if I take the robot somewhere else to demonstrate what it can do. What I would like to understand is why most of my network, using DHCP, is on the 10.x.x.x network and the Raspberry Pis seem to wind up with 192.168.1.xxx addresses.
One further wrinkle. We have two routers, the FIOS router, and a LinkSys WRT1900AC, which is the router on which WiFi is enabled.
I suspect this problem is caused by having the two routers or by something inherent in the way the Raspberry Pi interacts with DHCP.
I would like for my Raspberry Pi to configure with an IPv4 address I can use, no matter what network I am connecting it to, and I'd like to understand why this problem is happening in the first place.
Let me know what additional information you'd like to see.
* Additional Notes *
As to the comment that I have not done research. I spent a week reading through stackoverflow problems and reading up on documentation of DHCP without finding the answers to my question. I do not ask questions idley. I ask questions when I cannot find answers and need the help of people more expert than myself in the areas in which I am having trouble.
I have solved the login problem. It was a stupid password mistake.
So now I can login, over wifi, using the IPv6 address, but not with the IPv4 address.
On the FIOS router, both the 2.4 and 5GHz wifi channels are turned off.
As suggested by Ljm Dullaart, the problem was that there were two DHCP servers on the network. After I turned off the FIOS DHCP, my problems went away.

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