LAN-WAN Internet issue

[ashearera]

Hi guys,

I am setting up a small lab network for my MCSA studies, I wanted to have a seperate physical network so it doesnt interfere with my family but also, if possible, connect through the same internet connection for downloading software updates etc.

I have two routers: a TP Link TD-W8968 is the internet router for the house and an ASUS RT-N56U. An ethernet cable runs from LAN port of the TP-Link to the WAN port of the ASUS. The ASUS WAN port has been set to Automatically detect an IP address, and a DHCP reservation has been setup on the TP Link for it. Then the LAN IP of the ASUS is on a different subnet. i.e.:

TPLINK
WAN IP: Auto assigned by ISP
LAN IP: 192.168.1.1
DNS: Automatic
DHCP Enabled
NAT enabled (I think, I haven't seen any option to turn it off.... its as default)

ASUS
WAN IP: 192.168.1.2 (DHCP reservation from TP LINK's DHCP)
LAN IP: 192.168.2.1
DNS: Automatic
DHCP enabled
NAT Disabled

Hope this makes sense.

In this setup, all clients connected to the TP Link can browse the internet as normal, clients connected to the ASUS however cannot ping 192.168.1.2 or 192.168.1.1 - the Asus router reports the Internet status is connected and shows the correct reserved WAN IP, but I just get page cannot be displayed when attempting to access web pages on a client. THe clients do get IP addresses fine through DHCP, and they can obviously ping 192.168.2.1 which is the ASUS' LAN IP.

Can anyone suggest where I may be going wrong? I can get more specific details of router models and firmware versions etc. tonight.

Thank you!

 

[azazel1024]

May need to set the default gateway IP address on the Asus to point to the TP-Link. Alternately or in addition, you may need to set static DNS for the Asus.

 

[ashearera]

Ah apologies, forgot to say: the Default Gateway of the ASUS is set to 192.168.1.1 and both DNS servers are entered also as 192.168.1.1

 

[azazel1024]

DNS servers shouldn't be set to that. That is probably why it isn't working. The top level router is NOT functioning as a DNS server, so you aren't getting name resolution from the second internal network. Set it to auto or set it to something like Google's DNS, 8.8.8.8.

See if that works (I suspect it will).

 

[ashearera]

Now that you say that it does seem like an oversight, maybe I jsut wasnt paying attenting when I did that! Weird, I did test the other night just browsing to some IP addresses rather than URLs and that didn't work either... but I'll try this tonight and report back. Thanks!

 

[azazel1024]

Can you get address resolution at all? First I'd change the DNS entries for the router, but then I'd check a ping and see if you get resolution.

Try pinging www.msn.com or www.google.com and see if it'll work.

 

[ashearera]

Ok so I must have already resolved the DNS thing last night as when I got back to the router to check it was in fact set to Automatically obtain DNS - apologies for the confusion!

I noticed the ASUS firewall was on, so i turned that off to rule it out, however still no luck. If I try to browse to any web page I just get "Unable to connect to the Internet".

A ping of google (from my macbook, which receives an IP from the ASUS fine):

7 packets transmitted, 0 packets received, 100.0% packet loss
andrews-mbp:~ ashearera$ ping www.google.com
PING www.google.com (74.125.230.244): 56 data bytes
ping: sendto: No route to host
ping: sendto: No route to host
Request timeout for icmp_seq 0
Request timeout for icmp_seq 1
Request timeout for icmp_seq 2
Request timeout for icmp_seq 3

and a ping of 8.8.8.8:

andrews-mbp:~ ashearera$ ping 8.8.8.8
PING 8.8.8.8 (8.8.8.8): 56 data bytes
ping: sendto: No route to host
ping: sendto: No route to host
Request timeout for icmp_seq 0
ping: sendto: No route to host
Request timeout for icmp_seq 1
ping: sendto: No route to host
Request timeout for icmp_seq 2
ping: sendto: No route to host
Request timeout for icmp_seq 3

 

[azazel1024]

Try enabling NAT on the Asus. That or change the IP on it to 192.168.1.2 (and change the DHCP reservation range on the TP-Link to 192.168.3-whatever number).

I just noticed that NAT was disabled on the Asus.

 

[ashearera]

Hm, exactly the same symptoms with NAT enabled as disabled. Strange...

 

[azazel1024]

What happens with a client behind the Asus, with NAT disabled on the Asus, if you go in and manually enter a gateway IP address of 192.168.1.1 (the TP-Link router)?

 

[ashearera]

On my macbook, connected to the ASUS, I entered a manual router address of 192.168.1.1 which would be the TP Link. As I expected, the client cannot browse anything on the network or load any web pages, or get to the TP Link admin console as they are on different subnets... or should I also change the subnet of the client's IP? Not sure what that would test though....

From a few articles I've read online this should be a very simple setup, so I'm starting to suspect this is a problem with the asus somehow, I first bought it years ago to act as a main router and it really did not seem to want to stay connected to our BT connection... eventually I just replaced it with one of these TP links. Would be interesting to test with a linksys or something...

 

[azazel1024]

It is deffinitely sounding like an issue with the Asus router at this point. You could always try swapping the setup around. Stick the Asus at the internet head end and the TP-Link behind it and see if the issue persists. Or just swap in a cheap $20 router.

 

[ashearera]

Well, I ordered a cheap £20 Linksys E1200, plugged it in, setup my DHCP info etc. as I did in post 1 and it worked first time with no issues - I'm posting from a client on the lab subnet now.

I really don't have a good word to say about the ASUS RT-N56U, it has caused me nothing but issues since day 1 - given the number of positive reviews I've seen I think mine must have some sort of hardware defect, it was extremely flaky even when it did work...

Anyway, sorted now and thanks for your time azazel!

 

[azazel1024]

I am sorry you had such frustrations, but I am glad you have it working now.