Show the configured DNS server on a Unifi device from the CLI - networking

When I am connected to a Unifi network device via the shell (SSH/Putty/Unifi admin shell), how do I show the current DNS server that is configured?

Type the following and press Enter:
cat /etc/resolv.conf

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Connect "Network is Unreachable" VPS Centos

I've edited eth0 and I made a mistake where my VPS is now offline and can not even connect to ssh with this message to the Recovery Console:
"Network is unreachable".
What is the command to configure / edit the network!?
Photo
If you have access to your machine. For example via tty then you can edit the network interface. After that you should restart the machine.
See this link to edit the network config.
https://www.serverlab.ca/tutorials/linux/administration-linux/configure-centos-6-network-settings/
If you dont have any access to you machine then you have to reset the machine. Some vps hosters have a recovery mode you can try this too.

How to create ssh tunnel and keep in running

I want to access machine A which is behind the firewall through a jump host from machine B.
I want to do the same either via ssh keys or via username and password.
What will be the steps and the commands to achieve the same?
The feature is called port forwarding:
ssh -L localport:machine-a-address.domain:remote-port machine-b
Then you can simply use localpott on localhost to access the remote service on machine-a, for example:
telnet localhost localport

my guest can't get ip form my network dhcp?

i set below configuration for guest
image description here
but after set it and restart my guest, it can't get IP from my network DHCP!!!!
how can i solve it?
The network settings on virtualbox look good, as long as the interface is correct.
What is the guest os?
Have you tried the following on the vm?
if windows: run ipconfig /release then ipconfig /renew on cmd, or run diagnostics on the interface. You can also try to disable and enable the interface. If nothing works, try setting up a static IP in the same subnet as the dhcp server and check if the server is reachable via ping (if it's not, troubleshoot your network).
if linux: dhclient [interface], also check if the interface is set to static or dhcp, set the correct mode otherwise you will have to run dhclient again if you reboot or shutdown the vm

NETSH port forwarding from local port to local port not working

I'm trying to use NETSH PORTPROXY command to forward packets sent to my XP PC (IP 192.168.0.10) on port 8001 to port 80 (I've a XAMPP Apache server listening to port 80).
I issued the following:
netsh interface portproxy add v4tov4 listenport=8001 listenaddress=192.168.0.10 connectport=80 connectaddress=192.168.0.10
Show all confirms that everything is configured correctly:
netsh interface portproxy show all
Listen on IPv4: Connect to IPv4:
Address Port Address Port
--------------- ---------- --------------- ----------
192.168.0.10 8001 192.168.0.10 80
However, I'm not able to access apache website from http://localhost:8001. I'm able to access through the direct port at http://localhost as shown below.
Additionally, I've also tried the following:
1. Access the Apache website from a remote PC using the link: http://192.168.0.10:8001. Firewall turned off.
2. Changing listenaddress and connectaddress to 127.0.0.1.
Without further information, I can't find a way to resolve the problem. Is there a way to debug NETSH PORTPROXY?
Note: By the way, if you're wondering why I am doing this, I actually want to map remote MySQL client connections from a custom port to the default MySQL Server port 3306.
I managed to get it to work by issuing:
netsh interface ipv6 install
Also, for my purpose, it is not required to set listenaddress and better to set connectaddress=127.0.0.1, e.g.
netsh interface portproxy add v4tov4 listenport=8001 connectport=80 connectaddress=127.0.0.1
If netsh's port proxying is not working as expected, then you should verify the followings, preferably in that order:
Make sure the port proxy is properly configured
Start or restart the related Windows service
Ensure support for IPv6 is installed
Make sure the port is not blocked by a firewall
Make sure the port proxy is properly configured
This might seems to be trivial, but just in case, take the time to review your configuration before you go any further.
From either a command prompt or PowerShell prompt, run the following command:
netsh interface portproxy show all
The result should look something like this:
Listen on ipv4: Connect to ipv4:
Address Port Address Port
--------------- ---------- --------------- ----------
24.12.12.24 3306 192.168.0.100 3306
24.12.12.24 8080 192.168.0.100 80
Carefully review those settings. Make sure that you can indeed connect to the addresses on the right side of that list, from the local computer. For example, can you locally open a web browser and reach 192.168.0.100:80? If the protocol is not HTTP, then use telnet: telnet 192.168.0.100 3306 (see here for how to install the Telnet client on Windows).
Then, are the values on the left side correct? Is the IP address valid for your machine? Is that the port number you are trying to connect to, from the external machine?
Start or restart the related Windows service
On latest versions of Windows, netsh's port proxying is handled by a Windows service named "IP Helper" or "iphlpsvc". Proxying will obviously not work if that service is stopped. I have also faced situations that turned out to be resolved by restarting that service.
To do that in latest versions of Windows:
Open the Task manager, then go to the Services tab.
In the "Name" column, find the service named either "iphlpsvc" or "IP Helper".
Right click on that service, then select Restart. If restart is not available, then the service is probably stopped, and actually has to be started, so select Start.
On previous versions of Windows, look for Services in Administrative Tools, inside the Control Panel.
Ensure support for IPv6 is installed (older releases of Windows only)
On earlier versions of Windows (that is Windows XP, for sure, upto some early releases of Windows 10, apparently, though this is not clear), netsh's port proxying feature (including for IPv4-to-IPv4 proxys) was actually handled by a DLL (IPV6MON.DLL) that was only loaded if IPV6 protocol support was enabled. Therefore, on these versions, support for the IPv6 protocol is required in order to enable netsh's port proxying (see Microsoft's support article here).
From either a command prompt or PowerShell prompt, run the following command:
netsh interface ipv6 install
If you get an error indicating that command interface ipv6 install was not found, then it means that you are using a recent release of Windows, in which netsh's IPv6 support is implicit and cannot be disabled.
Make sure the port is not blocked by a firewall
A local firewall may potentially block the port even before they reach the IP Helper service. To make validate this hypothesis, temporarily disable any local firewall (including Windows' native firewall), then retest. If that works, then simply add a port exclusion to your firewall configuration.
I have the problem with you. I have solve it just now. There is a Windows Service named "IP Helper" that supplies the funcions tunnel connections. You should ensure it has been started.
You must Run Command.exe as Administrator first, by right-clicking the Command Prompt icon and choosing Run as Administrator. You will asked to confirm.
Paste your netsh Command in the command.exe window and press Enter.
If no error message is shown, the command worked.
In your web browser go to http://your-up:8001 to see it works.
The Windows Event Log might have information to help find the cause of a failure.

Meteor - accessing the app using public ip

I can access the app using localhost:3000 but I am trying to test from mobile devices locally, without having to deploy it. But I couldn't access the site.
I am allowing incoming request:
sudo ufw status verbose
Status: active
Logging: on (low)
Default: allow (incoming), allow (outgoing)
New profiles: skip
To Action From
-- ------ ----
3000/tcp ALLOW IN Anywhere
3000/tcp ALLOW IN Anywhere (v6)
I found that my ip address is 128.84.125.239 and so I visit 128.84.125.239:3000 and nothing happens.
This turned out to be an issue of using the right IP, or configuring the NAT of the router appropriately. Using a service such as cmyip.com will only provide you with your external IP address. This address can only reach your meteor app if your router is configured accordingly, i.e., the router will forward requests on port 3000 (or whichever port you are running your app on) to your server.
For testing on a mobile device during development you are most likely best off using your internal IP address, assuming your mobile device is on the same network as your app-serving machine.
On Linux you can use ifconfig to get your internal IPs. If you are connected via ethernet then you'll be looking for the device eth0 (in most cases). If you are connected over wifi, then the device you are looking for is typically called wlan0.
On Mac OSX you can use ifconfig as well, and look for devices called enX, where X is a number (often 0, or 2).
Your service is probably only running locally (on local ports, 127.0.0.0/8), To confirm this, run netstat -tulpn to see what services are running and on what ports/interfaces. If you don't see 0.0.0.0:3000 or 128.84.125.239:3000 then you won't be able to get ti it from the IP you are trying and you need to change the bind address of your app to be that IP (or all interaces).

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