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WINS Configuration Behind Router

David Walton
Occasional Visitor

WINS Configuration Behind Router

I've got a router set up that allows me to share my cable internet access between multiple pcs. This router also allows me to forward specific port requests on the isp assigned ip address to specific local ips as configured behind the router. Supposing my isp assigned ip is 95.94.93.92 and requests on port 80 should be forwarded to the local ip 192.168.0.2, here's an example of how this should work: With Apache running on my machine (OS: Windows 2000) (locally known as 192.168.0.2), if a remote internet request is made for http://95.94.93.92:80, the router will pass this along to my local ip where it is fielded by Apache & served. In practice, this works, sort of. If I am using any machine on the local network (with an ip of 192.168.0.*), I can browse http://95.94.93.92 with no problem. The router seems to be doing its job seamlessly. The problem is that when I try this from any remote computer, I get nothing. Now, if I ping my ip from my computer or any remote computer, the ping is processed. If I specify port 80, however, the ip fails to respond, even when I'm pinging from a local machine tethered to the router.
My question: Is it necessary to configure the WINS proxy in my local ip settings in order to let windows know that ping/info requests on port 80 locally are ok? Does this sound like something I should be configuring somewhere within Win2k security? Any help/info would be greatly appreciated.
6 REPLIES
Ron Kinner
Honored Contributor

Re: WINS Configuration Behind Router

It sounds more like a firewall/NAT issue. WINS just gives out names and is useful if you want to see something by browsing the network neighborhood. Since you are working with pure IP addresses it should not come into play.

NAT (Network Address Translation) changes a non registered address into a registered address when the packet goes through the router and toward the Internet (and vice versa in the other direction.

Normally a device on the local LAN can not see the NAT'd address of a server on the same LAN. It must use the local address to reach it. The fact that your local machines are able to reach the NAT'd address implies that your router is improperly setup. The router normally needs two network cards. One plugged into your cable modem and the second plugged into your local hub.

On a Cisco router you specify one network connection as Inside and the other as Outside then the router only NATs packets traveling from Inside to Outside or vice-versa.
Give me the the make and model number of your router and expalin how you have it conencted and I will see if there is enough info available on the web to figure out what the commands should be in order to make it work. (If by any chance it's a Cisco, just capture the output of show run and post it without your passwords and I can tell you what to do to make it work.)

Firewalls limit traffic based on a packet's source and destination and type. I'm not sure how you are trying to use a port 80 ping. Not sure there is such a thing since ping is ICMP which is separate from TCP and UDP which use port numbers but it's no surprise that it doesn't work. You can use telnet to test a connection by assigning a port other than the default 23. Usually the command is telnet A.B.C.D 80 but on some graphic based telnet you have to put it in under a drop down menu.

tracert -d A.B.C.D is also useful since it shows where the packet goes and does not try to get the name by going to the DNS server.

Ron
Ron Kinner
Honored Contributor

Re: WINS Configuration Behind Router

I forgot. If you feel you need WINS service you can add an entry for each local PC in a file named LMHOSTS. It already exists on a Windows PC so you can search for it. Just make sure that the TCP/IP setup under Networking in the control panel has the Use LMHOSTS box checked.

Normally this is only useful if you are trying to find a primary domain server and you have a router in between the pc and the server.

Ron
David Walton
Occasional Visitor

Re: WINS Configuration Behind Router

The router is an Etherfast Linksys Cable/DSL Router (Model #BEFSR41). The cable modem is fed to the WAN in port. My computer & the second computer are connected via the first 2 of the 4 ports. The router has a DHCP server built in and I've tried hosting with the option enabled and disabled, with the same result. The router does provide firewall protection but, supposedly, if an IP address is forwarded, web pages can be served, which I assumed meant that simple requests on forwarded ports would be granted. According to the documentation I have, I can also use the router's DMZ (de-militarized zone) Host capability and expose the nested IP to the outside world completely without firewall protection from the router, but when I tried that configuration, I continued to get the same errors. I'm not able to telnet in from an external computer right now, so I'm not sure what happens when an attempt is made as you described. I don't currently have any software set up to listen for incoming telnet attempts. What should I expect to see when I telnet the specified port?

Thanks for the quick reply yesterday, by the way. Hope this helps describe the situation a little better.
Ron Kinner
Honored Contributor

Re: WINS Configuration Behind Router

David,

Don't have time today but will probably get back to you tomorrow (Mon) PM. Looks like the website has enough info to figure it out.

Ron
Ron Kinner
Honored Contributor

Re: WINS Configuration Behind Router

Before I go into a lot of detail I need to know a few things.

Are you able to browse out through the router to the internet? (Is the router talking to the Cable Modem OK?)

Does the ISP provide the IP address?

In order to pass incoming requests into the html server you need to assign static IP addresses on the PCs and turn off the router's DHCP service.
Say the router's LAN address is 192.168.1.1 with mask 255.255.255.0. Make one computer 192.168.1.2 and the other 192.168.1.3 both with the same mask and with the 192.168.1.1 as the default gateway.

Finally, because of Code Red, many ISPs are now banning html servers and blocking port 80 incoming. Are you sure that yours allows it?

Ron

Patrick Ruane
Valued Contributor

Re: WINS Configuration Behind Router

It looks like you're having trouble setting up port forwarding. Check this link:

http://www.linksys.com/tech_helper/advanced.html

Extract:

Access the Router Setup Window by typing 192.168.1.1 in your browser's Address field.
Once you have entered your correct username and password to display the Setup Window, click on the "Advanced" tab, then click the "Forwarding" tab.

Under the "Forwarding" tab, enter the port(s) that your application uses under the "Service Port" field(s) - type in a number for each of the ports. Both the TCP and UDP ports are activated once you enter a port number in the field.

Then enter the IP address of the PC on the network that you would like the data to be forwarded to. Remember to assign a static IP address to that PC.

Let me know if you've already tried this, or if not, whether it works.
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