SIMPLE DNS questions - Can you help? 1

[mikeyddd]

I'm new to DNS, but can you help me:

1) I have simple computer network. Two computers behind a netgear router (machine1 and machine2).

2) I have a dyndns account set up, which is automatically updated (myname.dyndns.com).

3) If I'm at machine1, I can ping/ssh/access machine2.myname.dyndns.com with no problem. However, I cannot do this from outside my network on an external computer (for example, at a coffee shop or school computer).

4) Is the possible? Can I go to an external computer and access my home computer via machine2.myname.dyndns.com ?

5) Is this a feature of the router (to block this activity)?

6) If I install BIND on a Linux router, and set that up as my DNS server / router, can I set this kind of "externally-accessible" system up?

7) How would I go about doing this?

 

[WhoKilledKenny]

The simple answer is that your hosts are not know on the Internet. Meaning they do not have host records on the DNS servers that resolve names on the Internet. Your DNS server host records for you internal network only.

Couple of things to consider:
-It is possible to host your own external DNS, I have not done this but you can reasearch how.
- If your public IP address (provided by your ISP) is static you can connect via IP Address. You will have to open ports on your firewall to allow connection.
- My public IP is dynamic so I had to do the following. I registered a domain name, used a service from no-ip.com to host and change my public DNS record each time my IP changes, opened a port on my firewall that allows me to use RDP to connect to my machine at home.

 

[mikeyddd]

Thanks for reply.

Does anybody out there know how to "host your own external DNS".

I'm doing the port-forward thing right now, but I want to access machine1.myname.dyndns.com instead.

thanks.

 

[WhoKilledKenny]

Setting up External DNS Server.

http://www.microsoft.com/technet/se...d_Configure_External_DNS_Server.mspx?mfr=true

 

[lhuegele]

In your example, "machine1.myname.dyndns.com" the "machine1" part is considered a subdomain and may not be covered by Dyndns.

What you can do is set-up "machine1.dyndns.com" and "machine2.dyndns.com" but what you have to remember is that it's your router that is getting the external IP address, not your internal machines.

Hosting your own external DNS server won't help you either unless you are hosting your own external domain as well.

What I do is just use port forwarding on the router to get to my 2 machines at home. Since I never need the same things from them, that's not a problem for me. If I do need to access one of the other machines, I just remote desktop into one of them, then remote desktop from there into the other internal machine.

Hope this makes sense, and good luck.

 

[mikeyddd]

so it appears that i'm getting closer to the answer.

obviously, in order to access:

machine1.mydomain.com

from an external machine, the following needs to happen:

1) My DNS Broadcasting server needs to be connected to the

http://WWW somehow.

That is, from an external machine, I need to be able to access my networked machine via the following pathway: COM->MYDOMAIN->Machine1

I've got the COM->MYDOMAIN pointing to my router. However, I do not have my router "broadcasting" the Machine1 to the WWW.

2) According to one of the posts, in order for this to happen, I need to be hosting my own "external domain". What is the LINUX open source software for this? How is my domain "registered" in the WWW? That is, how do the backbone servers know that mydomain.com points to my "external domain" server? How do I register this?


Surely, there is a Ph.D. computer scientist out there that knows the right answer and can point me to the specific routing software.

 

[bradmg1]

Since your using dyndns this is no problem. Here is how you do it:

In dyndns you should have a record pointing to your domain.

example: mydomain.com

mydomain.com should have a current IP address the same as the IP address (external) on your router. If so, you are good to go. Now you can use the port forwarding capability of your router to access machines on your internal network. Access the routers webpage and look for port forwarding.

You can go beyond this by creating host records (A records (WWW,

http://WWW2,

FTP)) in dyndns and publishing services on your internal network. TSWeb (Terminal Services) comes to mind here. Keep in mind most ISPs block port 80 and others, though there are simple workarounds for this.

I would recommend you think about using a VPN to access your network to minimize your exposure to the web. PPTP though not perfect is a good solution and can be easy to implement.



Jeffrey Botsford
MCSE/CCNA/Cyber Forensics L1