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I have a computer A (190.21.8...) and B (190.21.5....) and C(222.104.100....) I can mstsc from A to B, and also - I have ping from A to C, and from A to B, but not from B to C?

How can this be fixed? For example, is it possible to add a route that will make B contact A and from there to C?

Thank you. ___forgot to mention - all pc computers

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migrated from stackoverflow.com May 22 '11 at 2:28

This question came from our site for professional and enthusiast programmers.

closed as not a real question by pauska, Mark Henderson Jul 4 '11 at 10:06

It's difficult to tell what is being asked here. This question is ambiguous, vague, incomplete, overly broad, or rhetorical and cannot be reasonably answered in its current form. For help clarifying this question so that it can be reopened, visit the help center.If this question can be reworded to fit the rules in the help center, please edit the question.

    
Is it possible that ICMP echo (ping) is blocked on the 190.21.5.* network? Also, is this for some household or small biz setup? If so, you need to use IP addresses in a range that you control -- or in one of the many private address blocks. –  debracey May 22 '11 at 2:06
    
Is there a specific reason you don't want B to contact C or is this design intent? If not you could add route to C on B and route to B on C and make them ping each other directly. –  Vijay May 22 '11 at 2:21
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This questions doesn't have anywhere near enough details to give a reasonable answer; there plenty of reasons this might be broke. The questioner is obviously not a system administrator. Thanks SO for another steaming shovel full. –  Chris S May 22 '11 at 2:41
    
@Chris S, I agree that this question doesn't have enough details, but that is not a sufficient condition to say it's unsalvagable; all you have to do is ask clarifying questions: we do this all day long on StackOverflow. The real problem here is that we have no way to communicate with @ComputeALot after the question has been migrated. I'm submitting to Meta as a case to see what should be done. –  Mike Pennington May 23 '11 at 2:38
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@Mike, "the real problem here is that" ComputeALot is not a System Administrator, as per the requirements stated in SF's FAQ this question should not have been migrated here. I know SO doesn't require prerequisite knowledge in the topic of the question, but this isn't SO, it's SF; thank you for appreciating the difference. User question related to a Windows environment (or "pc computers" as this user thinks all PCs inherently run Windows) should be migrated to SU; if it was related to a *nix environment unix.SE (probably) would have been a better fit. –  Chris S May 23 '11 at 3:25

1 Answer 1

Knowing the exact error would be helpful to debug this problem. Also this seems more like a sysadmin problem (superuser?). In any case, running traceroute would also help debug this problem.

But assuming that there is some administrative blocking of B->C, it is technically possible to go through A. It isn't a route, instead you need to create a tunnel (such as openvpn, or ipip, or any number of other tunnels) between B and A, then on A you would (typically) NAT or MASQUERADE B's IP address to A or some IP address assigned to A. C then is not aware of B's IP address. Packets travel from A to B through the tunnel (source B, destination C), B then rewrite the packet to, etc from A to C. C replies to B, B rewrite again from C to B, packet travels over tunnel.

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