Non routable networks

15 pts.
Network administration
Network routing
Network security
Hi, Please, I need someone to tell me what are non-routable networks and what are examples? Are there any security risks involved in having them? How can we mitigate those risks and if there are tools we can use, what are the examples? Thank you so much.

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Not 100% sure about your question, but here it goes.

A non routable network is, a network that is not “visible” in the Internet.
These are private networks; those which we use internally in our home and company intranets.

These are reserved IP address scopes that no router routes to the internet.
They provide a little extra security layer to the “internal” side of a network.

Ip addresses reserved for private networks: – – –

If you want to leaen alittle more about this, you can check the RFC 1597.


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  • Gabe9527
    Basically these are the IP addresses that you would use inside your firewall. These IP are not used on the internet so will not cause conflicting IP ranges if your users connected to a SITE somewhere. ie if you used the 209.85.169.X range you would get to a User that would conflict with Google. q: Are there any security risks involved in having them? a: There are your internal IP ranges... secure access to these from the outside world via Firewalls.... standard practice. q: How Can we mitigate those risks and if there are tools we can use, what are the examples? a: Control what can access your network Air defence - Manage Network Access - not just Windows
    11,095 pointsBadges:
  • TomLiotta
    In very simplified terms, networks are connected together through "routers". Routers use IP addresses to figure where to send data from one IP address to a different IP address on a different network. There are some IP addresses that have been designated as "non-routable". If your PC has a non-routable IP address, then another PC on a different network cannot connect to your IP address. The routers in between the two PCs simply discard the request. (That doesn't mean that connections can't be made between the two. It only means that the systems can't use the non-routable addresses to make connections. Routers can do other things like 'address translation' to allow you to control those situations.) By using non-routable addresses inside a network, it becomes possible for systems on different networks to have the same addresses. The addresses can be used over and over again, once on each network. (We'd have run out of new addresses long before now otherwise.) Perhaps nearly all local networks use non-routable addresses for the systems inside the networks. On the inside of a router, it doesn't matter. Pretty much every address can be connected to by any other address as long as the connection doesn't have to go through a router. Generally, however, addresses are assigned in local networks according to a pattern chosen by the network administrator rather than using 'just any address'. The patterns generally are called "subnets". And generally the security risks tend more to be in not using non-routable addresses. (Apologies for a double negative.) No matter how things are set up, there will always be risks. The question should come down to the relationship between cost and risk. Using non-routable addresses is practically no cost for eliminating nearly all risks of routable addresses. Other than a classroom exercise, what prompted the question? If it's a real-life scenario, there might be specifics that could be addressed. Tom
    125,585 pointsBadges:
  • 345E
    Thankyou guys for your help.
    15 pointsBadges:
  • Violett

    Can someone with experience of corporate network communication tell me am I right or not. I run the self-test training Microsoft Exam?
    It is about “non-routable” networks.
    Contoso company acquires Fabrikam, Inc. Both have a Windows Server 2012 R2 servers with the Hyper-v role installed. Both use System Center 2012 R2 Virtual Machine Manager (VMM) to manage the environment.
    CVM1 (of Contoso) must be able to communicate with a virtual machine named FVM2(of Fabrikam) on a non-routable subnet in the Fabrikam Hyper-V environment
    You need to ensure that CVM1 can communicate with FVM2.
    Which technology should you implement?

    A. Remote Desktop (RD) Gateway
    B. Windows Network Load Balancing (WNLB)
    C. Windows Server Gateway

    D. Reverse Proxy Server

    I think the answer is C.  'Windows Server Gateway'.

    Here, the keyword being “non-routable” networks, means two private networks inside of companies. And the communication between them goes through the  Internet. 
    There are different solutions how you manage this connection. From the choices of this question only C and can be A are meaningful. But I am curious if the experionced Administrator would be not agree with answer C.
    When I run some exam tests I always emagine the real scenarious. I am not Enterprise Administrator yet. I hope one day I'll be. [:)]

    With kind regards,

    30 pointsBadges:
  • Genderhayes

    is a network that uses private IP address space, following the standards set by for IPv4 and RFC 4193 for IPv6

    10,730 pointsBadges:
  • Violett
    Thank you, Genderhayes, for your attantion!

    Sorry for my late respond, I have only now discovered your respond on my question.

    About your question: I think  the both private networks using IP4 addresses. But as you can see it is not mentioned in Microsoft question.
    30 pointsBadges:

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