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Matt_Morrison
Posts: 11
Registered: ‎01-17-2007
Accepted Solution

Static DNS Issues

Hi there,
 
I have a small issue where I believe I have not configured my static DNS properly.  At the moment, all notebooks and PC's connect on a static IP to get internet access but I want them to be DHCP.
 
I have three routers as follows:
 
ADSL2MUE - IP: 192.168.1.1 (modem)
BEFVP41 - IP: 192.168.2.1 (VPN router)
WRT54GS - IP: 192.168.3.1 (wireless router)
 
The VPN and Wireless router both have the the 'Static DNS 1' set to: 192.168.1.1
Without this, I don't seem to get any webpages (can't ping www.google.com) but I think (if I remember correctly) I can connect via RDP to my server (not on the LAN).
 
Cheers, Matt :smileyhappy:
Expert
Expert
Posts: 12,649
Registered: ‎07-16-2006

Re: Static DNS Issues

First: why do you run three separate networks in your LAN? Is there a specific purpose for this? Generally it is not a good for most home LANs to run several subnets in a LAN as it makes things only terribly complicated. If there is no specific reason I would rather recommend to put everything into a single subnet instead of three.

Second: you don't write what DNS server your clients get from the router through DHCP. That would be very helpful to know. Check with "ipconfig /all" in a command prompt window. I suggest you post the DNS servers in the routers (from the Status page) and the clients (from ipconfig) have when running through DHCP (in the way you want it to work, i.e. without the static dns server configuration). Also please post the WAN interface configuration of the internal routers (BEF and WRT).

Third: the router's DHCP server usually either pass on or proxy the DNS servers they get on the WAN side. For instance, your BEF may give out its own address 192.168.2.1 through its DHCP server to clients connected to the BEF. The BEF will then be a proxy DNS server to the DNS servers which it will get on the WAN interface. If the WAN interface is automatic/DHCP it should use the the DNS server which the router got itself through DHCP. I guess that should be the 192.168.1.1 in your network if that is your main router (could be something else, if the main router hands out the IP address of your ISP's DNS servers instead of proxying).
Matt_Morrison
Posts: 11
Registered: ‎01-17-2007

Re: Static DNS Issues

Hi, firstly thank you for your help,
 
There is no reason for multiple subnets, I am a developer and not so good with networking!  The reason I configured on 1.1, 2.1, 3.1 etc is because the Linksys easy setup installer did this with just two routers so I extended that; not that either have ever worked effectively.
 
Forgetting the wireless for the time being, my VPN is 2.1 and behind the 1.1 modem router, my PC is connected wired to the 2.1 VPN, the 2.1 VPN is set to obtain an IP address automatically and has it's own address pool for it's DHCP clients.  When I change my PC IP and DNS to be dynamic, the DNS servers passed to the PC are: the modem (192.168.1.1 and 1.1); I can also confirm that I can RDP but not ping google.
 
Not sure if it's relevent but the Windows IP configuration says no IP routing is enabled?  Also the main router is 1.1, then 2.1 then 3.1 (modem, VPN, Wireless)
 
Cheers, Matt
Expert
Expert
Posts: 12,649
Registered: ‎07-16-2006

Re: Static DNS Issues

First, please check what mode the two internal routers are running: gateway or router mode. On the WRT you should find the configuration on the Advanced Routing tab. The BEF should have something similar. Both routers should be in Gateway mode.

Next, on a computer setup for DHCP connected to one of the internal routers (i.e. it gets the DNS server address 192.168.1.1) open a command prompt window again and enter:

nslookup

It should reply with the standard server name and address which should be 192.168.1.1 again for you. Then you see the sign ">" for the prompt. Simply enter "www.google.com" and press enter. If it cannot resolve the name you'll get an error message. Please post the exact error message.

As I wrote before, I would however not recommend your kind of setup. With this setup, you are for instance not able to use workgroup browsing across the routers. Also you are not able to access a computer in the internal router's LAN from the main router's LAN.

I would rather suggest that you put all internal routers in your main router's LAN. That way you only have a single LAN 192.168.1.*. The WRT would mainly work as wireless access point and hardware switch. The BEF would be mainly a switch and VPN server if necessary.

My suggestion for you would be to assign the LAN IP address 192.168.1.2 to the BEF and the LAN IP address 192.168.1.3 to the WRT. Turn off the DHCP servers on the WRT and BEF. Now connect the BEF and WRT using a numbered LAN port to the main router. The internet/WAN port of the BEF and WRT remain unused! You can ignore the internet connection settings in the BEF and WRT.

With this kind of setup anything wired to the BEF or WRT is basically connected through a simple switch to the main router. The wireless clients also are bridged into your LAN. All computers connected get their IP address from the DHCP server of the main router. All computers use the main router as internet gateway. All computers will also use the DNS proxy server on the main router. As there is no router involved anymore between a computer connected to the BEF or WRT and the main router, they can directly access the main router and there should be no access problems.

Also, with this setup you can use standard file and printer sharing with Windows and name resolution works fine throughout the whole LAN.
Matt_Morrison
Posts: 11
Registered: ‎01-17-2007

Re: Static DNS Issues

I want to share in a workgroup and I also want to follow your recommendations.  Therefore, I have followed the guidelines you gave me and I still have no connection...
 
  1. I turned off the DHCP Server on WRT & BEF, which also disabled the static DNS and IP address pool configuration etc
  2. I changed the BEF IP to 192.168.1.2 and the WRT to 192.168.1.3
  3. I also connected the modem ethernet to LAN port 1 on the BEF; nothing in WAN port (internet port)
  4. Then I connected the BEF on LAN port 4 (uplink port) to WRT LAN port 1; again nothing in WAN port.
  5. I then connected my PC to port 2 on the BEF
  6. No connection available...so...
  7. ipconfig gave me 1.1 on gateway and dns servers 1 & 2
  8. Then I did nslookup, which said the following:

*** Can't find server name for address 192.168.1.1: No response from server
*** Default servers are not available
Default Server:  UnKnown
Address:  192.168.1.1

>www.google.com
Server:  UnKnown
Address:  192.168.1.1

*** UnKnown can't find www.google.com: No response from server
>

I just wanted to say you are being very helpful, thank you!  I've also learned something new... I thought that the subnet mask defined the subnet but I was being so silly, of course!  It's a mask, not the actual subnet! haha :smileyvery-happy:

Expert
Expert
Posts: 12,649
Registered: ‎07-16-2006

Re: Static DNS Issues

Can you please verify that a computer directly connected to the modem does work and has internet without modifications?

Does the computer really have DHCP set up? Could you open a command prompt window ("Run..." and enter "cmd"), and run the command

ipconfig /all

Please copy the output into your next post.
Matt_Morrison
Posts: 11
Registered: ‎01-17-2007

Re: Static DNS Issues

Well I haven't tried directly connecting the PC to the modem yet but here is the ipconfig /all results...

Microsoft Windows XP [Version 5.1.2600]
(C) Copyright 1985-2001 Microsoft Corp.
C:\Documents and Settings\Matthew Morrison>ipconfig /all
Windows IP Configuration
       Host Name . . . . . . . . . . . . : firenet-pc01
       Primary Dns Suffix  . . . . . . . :
       Node Type . . . . . . . . . . . . : Unknown
       IP Routing Enabled. . . . . . . . : No
       WINS Proxy Enabled. . . . . . . . : No
Ethernet adapter VMware Network Adapter VMnet8:
       Connection-specific DNS Suffix  . :
       Description . . . . . . . . . . . : VMware Virtual Ethernet Adapter for
VMnet8
       Physical Address. . . . . . . . . : 00-50-56-C0-00-08
       Dhcp Enabled. . . . . . . . . . . : No
       IP Address. . . . . . . . . . . . : 192.168.47.1
       Subnet Mask . . . . . . . . . . . : 255.255.255.0
       Default Gateway . . . . . . . . . :
Ethernet adapter VMware Network Adapter VMnet1:
       Connection-specific DNS Suffix  . :
       Description . . . . . . . . . . . : VMware Virtual Ethernet Adapter for
VMnet1
       Physical Address. . . . . . . . . : 00-50-56-C0-00-01
       Dhcp Enabled. . . . . . . . . . . : No
       IP Address. . . . . . . . . . . . : 192.168.126.1
       Subnet Mask . . . . . . . . . . . : 255.255.255.0
       Default Gateway . . . . . . . . . :
Ethernet adapter Local Area Connection:
       Connection-specific DNS Suffix  . :
       Description . . . . . . . . . . . : VIA Rhine II Fast Ethernet Adapter
       Physical Address. . . . . . . . . : 00-30-18-B0-43-11
       Dhcp Enabled. . . . . . . . . . . : Yes
       Autoconfiguration Enabled . . . . : Yes
       IP Address. . . . . . . . . . . . : 192.168.1.102
       Subnet Mask . . . . . . . . . . . : 255.255.255.0
       Default Gateway . . . . . . . . . : 192.168.1.1
       DHCP Server . . . . . . . . . . . : 192.168.1.1
       DNS Servers . . . . . . . . . . . : 192.168.1.1
       Lease Obtained. . . . . . . . . . : 18 January 2007 11:31:19
       Lease Expires . . . . . . . . . . : 18 January 2007 12:31:19
C:\Documents and Settings\Matthew Morrison>
Matt_Morrison
Posts: 11
Registered: ‎01-17-2007

Re: Static DNS Issues

[ Edited ]
Ok, I have tried connecting directly to the modem but exactly the same happens.
 
I can ping external IP's but not ping google; nslookup on google doesn't resolve either.
 
I have only a USB and Ethernet port on the back of the ADSL2MUE, I only tried using ethernet direct from my PC; not the USB, shouldn't make a difference should it?
 
Anyway, the modem connects fine to the ISP and all the settings are correct i.e. PPPoATM VPI 0 VCI 38.  There doesn't seem to be much more to the webadmin; it's pretty basic.

Message Edited by Matt_Morrison on 01-18-200704:50 AM

Matt_Morrison
Posts: 11
Registered: ‎01-17-2007

Re: Static DNS Issues

[ Edited ]
I had an idea... I would like to do the following, can you advise if this is ok?
 
  1. Turn off the DHCP on the ADSL2MUE, leave the IP as 192.168.1.1
  2. Put it into bridge mode
  3. Turn on the DHCP on the BEF and leave the IP as 192.168.1.2
  4. Then configure the BEF to have static IP and DNS because there is no problem with the connection to the ISP from the modem and the webconfig is very basic.

What do you think?

Message Edited by Matt_Morrison on 01-18-200705:17 AM

Expert
Expert
Posts: 12,649
Registered: ‎07-16-2006

Re: Static DNS Issues

Generally it is a good idea to put the modem into bridge mode. However, it won't work for you: you are using PPPoA on the line. When you put the modem into bridge mode, it works as modem only. Your router must be able to do PPPoA then which I doubt it will.

I don't know which operating modes the modem has. Thus I can only guess here. But I guess the only way to get this working would be to leave the modem in router mode. Then you use the BEF as router for your LAN. Therefore you must configure a different subnet on the BEF for your LAN. Otherwise you have address conflicts. You could choose the LAN IP address 192.168.2.1 for your BEF with subnet mask 255.255.255.0. Configure the internet connection of the BEF for DHCP. Now you connect the modem with the internet port of the BEF. All clients in your network should use DHCP also for IP address and DNS servers.

This setup should work to give you an internet connection and DNS access. Check if/what is working with this setup. You should still check the modem and the manual to see what operating modes it has. Let me know. Maybe we'll find a better solution.