How to determine source of mysterious server name on my network - network-security

Over the last few days I have noticed a mysterious (unknown to me) server hostname that shows up on both Ubuntu's Nautilus Network section as well as Windows File Manager network group. The hostname does not show in the list of clients on my router. If I double click the hostname icon to try to connect to it I get a connection refused error. The hostname's appearance is random.
I have non-factory admin and wireless passwords set on my router as well as MAC filtering. Router firewall is on and no unneeded service ports are opened (NFS, etc.).
How can I determine the source of this unknown hostname and how can I close down my network in case this is really someone that has managed to break into my network? Also, if I have explicitly listed the MAC addresses of all my devices how could a non-listed device be able to connect?
Thank you for any comments you can provide.

Resolved; see previous comment on NetBios over TCP/IP.

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XAMPP/Wordpress is using a different IP address after new modem

So my ip address has changed so I can no longer access my WP Admin from my pc. It's redirecting to a different device/ip on my wifi so, therefore, cannot access it on my PC anymore. Can I edit/reset the Wordpress settings from ftp or PHPMyAdmin? So it points to localhost instead of a different device ip?
I also had a problem with my windows ten (my other Samsung Computer)
So I searched this up.
https://kinsta.com/knowledgebase/xampp-not-working/
This actually contains 3 common solutions to the problems that we both have had and are having.
Resolve Apache Port Conflicts (This actually fixed my problem)
Include the Listening Port in the Address When Accessing Localhost
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For more explanation, click on the link above.

How to setup SQL Server Express on local network with wireless router

Guidance on how to connect to SQL Server 2012 needed.
I am on Windows 10 Home Edition
I have set up SQL Server Express to allow remote connections on my database machine to serve up data to three client machines.
Firewall has been set for ports - check
Allowed mixed mode logins - check
Setup IPs through SQL Configuration Manager - check
The server is something like 192.168.1.40,1433 and I can login successfully through SQL Server Express on my client machines. I had a long LAN cable running along the floor which is not optimal. So, I went to the store and bought a router so that I could connect wirelessly but have limited experience in networking.
After, installation of the router I can no longer connect to SQL Server. This makes sense since there is another piece of hardware in the chain.
After doing an IP config on the command line I see that the IPV4 address has changed. I assume I am not picking up the private IP address of the router rather than the modem that I was initially connected to.
Should I be port forwarding?
What are my options?
I explored what I thought may be reasonable leads to get this working.
First, I tried to create a virtual server (I also assume this is how to port forward on my particular router). I didn't really know what to put in five fields that were given other than server name and Protocol TCP or if I was on the right track at all.
The other three fields consist of:
External Port, Internal IP, and Internal Port
If this is a reasonable solution can you let me know what to put in these fields and any changes to the SQL Server configuration or firewall might be?
Should I VPN ?
After exploring this option on google I also notice people saying, "set up a VPN is the correct way to go." However, I don't really know how to do this. The only VPNs I know of are external VPN providers. It seems that I would be setting up a VPN server if I am not corrected(maybe on the server computer) and connecting via my client machines.
Any clarification or direction would be greatly appreciated. I am sure I have missed the mark on many things here but still would like to make ground.

Allow lan segments to ping each other on multihomed router

I have a box running OpenSuse with two local network segments:
192.168.2.0/24 (lan0)
192.168.33.0/24 (vlan0)
and 3rd connection,
DHCP (wan), used for Internet access.
and I'd like to be able to route everything (tcp, udp, icmp, whatever) in lan0 and vlan0 segments.
I have enabled ip forwarding and ip masquarading using YaST. I also added both 192.168.xx.0/24 to trusted networks in SuSEfirewall2 and set up explicit routing in FW_ROUTE setting. rp_filter is off for both.
I have internet access on both segments and i am able to ping in both directions (router - pc on the segment) but cannot ping from lan0's machine to vlan0's one. I get 'destination host unreachable' error whenever I try to ping from lan0 to vlan0.
My understanding is i am missing some major settings which would let router route packets from lan0 to vlan0 instead of masquarading them and sending to the Internet. Windows boxes at lan0/vlan0 do not see each other too :(
Any help would be greatly appreciated.
In case someone runs into same problem - it appeared that pings do not work for Windows 10 boxes only. Android phone pings fine so the root cause is not OpenSuse box at all.

Connect to my localhost from another computer NOT in the same network

I have a real IP. Or so I think, basically how I tested this is under windows in cmd I pinged my IP address and I got packages back, so that must mean it's real. However when I start my xampp and go to my IP address in the browser I get
Unable to connect
Firefox can't establish a connection to the server
I tried looking up other questions but they didn't help cause all answers I found were suggesting LAN connection. Can you please explain to me any extra steps I need to take or link an answer that does that. Thanks!
The only way to access your localhost from other computers is over a Local Area Network (LAN); whether wired or wireless, there has to be a physical connection between the computers.
Once the computers are connected, you can access your localhost from the browser with the name of the computer on other computers:
http ://your-computer/path/to/files/
It also works on the same computer, so you can test it there.
You can find the name of your computer by going to the "Network" section in Windows Explorer.
EDIT:
If you want to access a localhost from a computer that is on another network, you have to create a web server; more or less what you would be paying for from a hosting company. Here is how you would do it:
http://arstechnica.com/gadgets/2012/11/how-to-set-up-a-safe-and-secure-web-server/

Share the internet access from laptop to beaglebone black and then access it through VNC server

I am trying to share the internet with the Beaglebone Black from my laptop. Here is what I tried till now-
I connected Beaglebone Black to my laptop running Windows 8 via USB cable. Then, I went to network and sharing center. Then, the network which I want to share, I shared it with the Beaglebone(It says Local Area Connection). Now, I went to the Gate one SSH on Beaglebone and wrote - "ping www.google.com". But it said "Unknown Host".
Now, since the above didn't work, I connected the Beaglebone Black with the standard ethernet cable and again tried sharing my network, but it still didn't work.
Here is what I am trying to do-
If I am able to connect to internet, I want to set up VNC server and through that I want to load the GUI of linux on my laptop.
Any help will be greatly appreciated. If there is any other method to accomplish this, please tell me about it. I have tried most of the tutorials on the internet, but didn't succeed.
Here is the detailed answer, after long long waiting I finally figured out how to share internet on BBB. This question is being seen at least 10 times everyday so I though I should answer it by my own. (Also SO gave me Popular question badge for this!)
First thing I tried was:
I connected the BBB(running angstrom) to laptop (running windows 8). The laptop recognized the device and I was able to SSH it through putty.
Now, I tried to ping my computer back whose IP address is 192.168.7.1 .. This step never worked for me, my BBB was never able to ping my computer back but, I was able to ping the beaglebone itself through the provided IP that is 192.168.7.2 (which is obvious)
I searched everywhere on internet and did everything to overcome this glitch such as:
I made the default gateway in BBB to 192.168.7.1
/sbin/route add default gw 192.168.7.1
but that also didn't worked.
I previously thought that it is necessary for me to ping 192.168.7.1 in order to get the internet on BBB.
Since nothing was working I decided to skip this step.
I simply connected the BBB, and then went to network and sharing center in windows 8 and from there, I shared the internet connection from my wifi connection to the beaglebone.
As you will do this, you will see that BB will loose its connection from the putty (if you started putty before network sharing), This is because computer assigns an IP to the BB which you have to change to 'Obtain the IP automatially'
To do this right click and go to properties of the BB connection and then from the list select the IPV4 tcp/IP and go to its properties. In that, you will see the option 'Obtain IP automatically'
Now again start putty (as previous connection will get terminated) and you will see that BB is able to connect.
Now simply add the default gateway as I showed above and then you will be able to ping 8.8.8.8 or any other IP address. Now, simply add the nameserver like this:
cd /etc
more resolv.conf
nano resolv.conf
and add this line below nameserver 127.0.0.1
nameserver 8.8.8.8
and save it, you will be able to ping google.com.
Now comes the VNC server part. For that case also I was wrong. To connect to VNC server you do not need internet connection on the BBB. Yes, you will need that for installing the VNC server on it but not afterwards. Once it is installed, you have to simple do this in BB:
x11vnc -bg -o %HOME/.x11vnc.log.%VNCDISPLAY -auth /var/run/gdm/auth-for-gdm*/database -display :0 -forever
and press enter and BB will reply with VNC started at port 5900
Thats it, now comeback to windows and start VNC server, add the address 192.168.7.2 and you can see the GUI on the screen. I am also able surf internet on the beaglebone.
Thank you for the support and if I am wrong here in my question then please notify me.
Also if you have any doubt, refer to this awesome video my derek molloy: He has explained it very well and remember to skip the step of pinging back 192.168.7.1 if it is not working.
I have not yet figured it out. I will edit the answer once I get it.
1) On your Beaglebone:
sudo su
ifconfig usb0 192.168.7.2
route add default gw 192.168.7.1
2) Now share the network and make sure your pc's ip is 192.168.7.1 after you do
connect beaglebone black to router via ethernet
now use
adb tcpip 5555
adb connect bbb_ip:5555 then use adb shell
The problem you're facing is of resolving nameservers. If you're able to access the device through SSH (using PuTTy, for example), then you can provide it internet too- but the device needs to know where to look for.
The BeagleBone Black has a utility called Connman that manages its connections.
/usr/lib/connman/test has functions related to it.
Use ./set-ipv4-method in there to set different values. Be sure to set the nameservers right. If in doubt, use 8.8.8.8 as the only entry. Also note that the gateway for your BeagleBone must be your computer.
If you're not a newbie and need more detailed instructions, see this.
To continue from the answer provide by Vikas Arora, 3 things you have to do primarily to provide ethernet over usb connection to your Beaglebone. Firstly, share your PC internet connection with the local network made with Beaglebone, a process well explained above. And also setting up the IP address to be obtained automatically.
Secondly, setting up the nameserver to the public DNS server address 8.8.8.8 also explained above. But this setting is not persistent i.e. once you reboot, the settings will be lost. It is because the network manager on Angstrom 'connman' resets the etc/resolv.conf on startup. To correct that I disabled the connman service on my device by going to /lib/systemd/system and
firing commands
systemctl stop connman.service
systemctl disable connman.service
This will make your nameserver file persistent and you can always start connman service again if you need.
Thirdly you have to set your gateway to the address of your internet sharing machine also explained above. But this setting is also not persistent. To do that make a script like below in your home directory
echo "********Setting up the default gateway"
route add default gw 192.168.7.1
and make a service that will kick off on startup and trigger your script. A process well explained at
https://askubuntu.com/questions/506167/how-do-you-save-the-routing-table-on-the-beaglebone-blackangstrom
and
http://mattrichardson.com/BeagleBone-System-Services/

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