I have 2 computers on my private network behind a router (with a public IP). The public IP is DHCP and therefore keeps changing. I have setup dynamic DNS hosts to point to my updated public IP.

I have two dynamic DNS hosts pointing to the same public IP.

server1.dynamichost.com --> Public IP

server2.dynamichost.com --> Public IP

Question: if there is a solution to have the dynamic hosts route to my private IPs like this:

server1.dynamichost.com --> Public IP --> (Private IP)

server2.dynamichost.com --> Public IP --> (Private IP)

What do I need to do for this to work?

Thanks much!

  • what model of router do you have? – John Kennedy Dec 26 '13 at 20:18
  • Apple Airport Extreme - not really a customisable router, but I can replace it if I find a working solution. – Daniel Matei Dec 26 '13 at 20:29
  • Unfortunately, this is question is not about network engineering as defined in the "On Topic" guidelines. Have you seen Super User? It is geared more towards these types of questions. Specifically it looks like you're looking for information on how to do NAT/PAT on consumer networking equipment, which would fall outside of the Network Engineering area of focus. – Brett Lykins Dec 26 '13 at 20:41

No, but you can have your router perform port redirection (or static PAT or port translation, they are just different names for the same technologies).

For instance, if you needed ssh access to, you could configure your router to forward connections on TCP port 22 of its public IP to your private IP. If you wanted to have RDP forwarded to, the same logic would apply.

Most routers can also do translation as part of this process. I.e. you can have your router forward connections to port 9001 (external) to on port 22, and connections to port 9002 (external) to on port 22.

  • Many thanks for reply. I would like to access port 22 and port 80 on both *1 and *2 private computers. So there is no other solution than using different ports to route to one or other private IP?! – Daniel Matei Dec 26 '13 at 20:42
  • you can make a configuration like this: ports 22 and 80 get forwarded to ports 22 and 80 respectively on PC 1. Ports 23 and 81 get forwarded to ports 22 and 80 respectively on PC2. Your question "is there no other solution" is rather vague. You can buy an NLB or configure microsoft NLB if we're talking about servers in a cluster which might technically fulfill what you are talking about, but not how you think it will. I concur with Brett's comment on your origonal question – John Kennedy Dec 26 '13 at 20:58
  • Thanks John. I will use your suggestion. You're right I'm not looking for enterprise solutions, it's only for personal use. And sorry for posting the Q in the wrong corner. – Daniel Matei Dec 26 '13 at 21:40

For web traffic, it is possible but requires additional configuration on your internal server (assuming that you can't set up your router to do the redirection). The bad news is that your web server needs to be able to proxy one of the domains or you need to set up a proxy to redirect both.

Question: why not just use virtual hosts on a single web server? Most modern web services are capable of such, and you won't have to redirect or proxy anything.

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