How to know which machine the remote machine will connect to? - security

I am taking my first network class and I came across a question I just cant wrap my head around.
We have an external machine that has a public IP address from using NAT, the external machine want to contact one other machines but using their local IP address no the one public provided by NAT. How can initiate the connection in order for the remote machine to contact the local one?
Any tips would be highly appreciated

Related

How can I connect to an IIS site being served on my computer from my iPad?

Both devices are connected to the same WiFi network.
I have set IIS bindings to allow connections to my IP:
However, my computer's IP address is the same as my iPad's.
Is there a way to make this work?
That's not your IP. Every time you use a laptop on a Wifi network, you'll be using the public IP address of whatever network you're on.
The IP address of "your" computer doesn't belong to your computer. It belongs to the network you're connected to. Your computer is just borrowing it for a while.
Try to set a static IP address for your computer and use another machine to send ping command to it. Then use iPad to connect.
Initially when I posted this question, I was using an xfinitywifi hotspot and I assume that came with a whole host of problems. Full-disclosure, I did not figure out how to make it work in this scenario.
However when I moved to my own home wifi network, I was still having this problem.
I had to do two things, one of which, I know is not recommended, but it was really easy.
First, I had to enter my network and sharing center and set my connection as home connection instead of public which is what I previously had it at.
Second, which is not recommended, I turned off Windows firewall. I only do this when I need to access my site from another device for debugging. I turn it back on when I am done. For a more permanent setup I know it is recommended to just enable the port you need, but I could not figure this out.

Which kind of network should i choose to setup a Satndalone Spark Cluster

I have 2 PC (with Windows as default OS), let's say PC_master and PC_slave. Since it is recommended to work with Linux to manage a spark Cluster i created one Virtual Machines with Linux on each of theses PC: VM_master on PC_master and VM_slave on PC_slave.
I would like to setup a Standalone Spark Cluster, so which Networking configuration should i use (NAT, Bridge, HostOnly?) for theses 2VM in order that they own their private IP adress letting me ssh from one to another without the need of port forwarding ?
Edit: My two laptop are linked to the same box, so they have private IP and supposed to be linked to the same router.
Finally it seems that if i want to give each VM its own Ip adress to create a private Network i have to choose Bridge Network which will assign a unique Ip for each VM!

Remote ssh with no router configuration

I will be sending a linux machine to a non technical customer overseas. After the customer has connected the machine to his LAN , which is also connected to the Internet, I want to be able to ssh into this machine without requiring the customer to do any router configuration (no port forwarding for instance).
The linux machine is connected to the internet through a router. It does not have a public ip address.
Is this possible using ssh configuration only?
If not then what is the simplest way to achieve this?
I used to work in a place where we had a setup that allowed for this, but unfortunately I can't remember the details - here is are the basics of the setup though.
The customers machine would connect using SSH to a machine with a known hostname using the -R option to ssh to setup a reverse port forward. We could then connect to the known machine and use the forwarded port to get to port 22 on the customers machine.
Sorry I can't remember more, but it worked absolutely perfect :)
If that linux system is directly connected with modem then it must have public ip address so you will able to access that linux system from anywhere . but make sure the remote system has static public ip address otherwise you need to do dynamic dns.

Accessing vitual linux-system

I have just installed an virtual Linux system. I was trying to access is from a different location but I could get trough.
When I have looked up the ip-address (ifconfig) on the system, which is:
inet addr: 10.0.2.15
but I still cant seem to manage it. Can anyone help?
It depends on virtualizing software you're using, but address pretty much looks like NATed. In that case you can't directly access it, unless you'll configure VM to map virtual network controller directly to host network.
What do you mean with different location? 10.x.x.x are private IP addresses, which can only be accessed within its subnet. What IP address does the host system have?
If the host system is within 192.168.x.x subnet, then an outside computer cannot know how to access 10.x.x.x when there is no route. You have then to set up NAT on your host computer.
A more easier approach would be to use bridged networking which will then eventually get an IP address through DHCP from your router (or whatever you might have).

ossec Setup with Virtual Machine

How does one set up ossec to have the host work as a server, and the guests have agents in them? Specifically, at least one point in the installation confuses me as to how this would work-how do you set the sever IP, if you are running ossec on a laptop, the IP address will change. How do you resolve the host that is running the guests ip dynamically?
Maybe the question should in that case be retitled to that, but the base cause for asking this question is for an ossec setup, and I will likely have more questions later, I'd rather them all be related to this.
Perhaps there is a guide to explain how to do what I want, which is to set up a mac os X lion host running ossec as the server, and have several vm guests with agent setups on them that talk to the host.
One deployment scenario is to create one OSSEC server and then to install OSSEC agents on everything you would like to watch for security events.
Regarding DHCP configured OSSEC agents, you can check out "Agent systems behind NAT or with dynamic IPs (DHCP)" http://www.ossec.net/doc/manual/agent/agent-dhcp-nat.html
If you have a specific DHCP or network range you would like any OSSEC agent to be able use and to be able to connect to the OSSEC server, then you can modify the following lines in the ossec.conf file (snippet borrowed from the OSSEC book):
We can also use the <allowed-ips></allowed-ips> tag to explicitly state which IP address
we allow connections from. In the following example, we used the <allowed-ips></allowed-ips>
tag in conjunction with the <connection></connection> tag to indicate that we expect OSSEC
HIDS agent connections from the 192.168.10.0/24 network
<ossec_config>
<remote>
<connection>secure</connection>
<allowed-ips>192.168.10.0/24</allowed-ips>
</remote>
</ossec_config>
I found out from vmware that the host VM's that are using a NAT configuration have a static IP address that corresponds to the host: 192.168.231.1 will reach the host from within the guest VM. This way, when you set up agents within the guest VM's you can use this address, and it will work.

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