Configure RTN66U as a wifi access point with DHCP server for connected devices

[dboy]

I am between two internet providers. Will be another 2 months until I get fibre connection up and going.
Meanwhile, I have set up an old PC running WinXP with a GSM SIM card connected to the net via 3G. I share its connection on my LAN via the ethernet port connected to a switch.

All work fine as long as I use static IP addressing on all connected devices. I can surf fine on cable connected ethernet computers.

I have assigned the RTN66U a static adress, 192.168.0.2, on the LAN, so it is connected on the LAN. It works fine to connect to the RTN66U via wifi, and it assigns IP addresses to wifi connected devices via its DHCP server. However, no traffic is routed via the WiFi port on the RTN66U to/from the WinXP PC to the internet.

I am not using the WAN port on the router. I have tried to connect an ethernet cable from the WinXP computer to the RTN66U WAN port, but that seems not to work, it seems the WAN port can not talk directly to the pc sharing a connection. I don't fully understand if I need to configure the WAN on the RTN66U in some specific way for this to possibly work..

Anyone know how to configure this?

SetUp:
Internet - GSM-WinXP-Ethernet(192.168.0.1)-> external switch
Switch-ports connected to several devices with static Ipadresses in the range 192.168.0.100--254

RTN66U configured as 192.168.0.2, several devices are handed IP addresses via the RTN66U DHCP server.

 

[ColinTaylor]

It sounds like you've setup the XP machine for ICS. Yes?

If this is the case then from what I understand (as I don't use it myself) the ASUS should be put into "Access Point(AP) mode". It should not be running DHCP or DNS, the PC will be providing that.

http://windows.microsoft.com/en-gb/windows/using-internet-connection-sharing#1TC=windows-7

Don't use ICS on a network with domain controllers, DNS servers, gateways, or DHCP servers. And don't use ICS on systems configured for static IP addresses.

 

[coldwizard]

SetUp:
Internet - GSM-WinXP-Ethernet(192.168.0.1)-> external switch
Switch-ports connected to several devices with static Ipadresses in the range 192.168.0.100--254

RTN66U configured as 192.168.0.2, several devices are handed IP addresses via the RTN66U DHCP server.

You said that devices configured statically connected to the WinXP work correctly getting INternet access. You are configuring more than just the IP address on the device, but setting the gateway and DNS servers. Am I right? Assuming yes answer .. try the following.

Leave the RT-N66U in router mode! Treat the GSM-WinXP as your temporary ISP modem. Since this fake ISP uses IP range 192.168.0.x, you need to assign the LAN on the N66U a different range, say 192.168.99.x.
(1) Assign the LAN on the N66U to 192.168.99.10. Reboot N66U and connect to N66U via LAN port or wireless to get back to configuration GUI on N66U.
(2) Now configure the N66U WAN for the fake ISP requiring a static configuration. You set N66U WAN IP address to 192.168.0.2, gateway to 192.168.0.1, and assign static DNS server numbers.

(3) Connect the WAN cable to the GSM-WinXP (ISP), reboot the N66U and you should be good to go. B0th the LAN ports and wireless of the N66U should work.

(Later) when you get a real ISP, you just need to reconfigure the WAN on the N66U in step (2) as required by your new ISP, and reboot N66U. The LAN configuration can remain unchanged.

 

[dboy]

Thank you all,
There was a second answer when I checked earlier, but it is gone now. Is there a bug in the forum software?

Anyway, ColinTaylors advice made me check ICS and it turns out the problem may be the ICS-DHCP server. I had a network with ~20 clients, and I think there may have been several IP conflicts. I solved them by assigning static addresses, which again, would be in conflict with the DHCP assigned addresses from the ICS computer. This could also possibly explain some unexplained strange drops in the internet connection from 5-60 s long once an hour or so.

So, it seems, I need to restrict the range of DHCP addresses haded out from the ICS computer.

I will try:
1. to restrict the ICS DHCP range to only one address using this link
http://www.windowsnetworking.com/j_helmig/icsadcnf.htm

2. then try the advice from the second replyer, who's post got lost somehow. Will be interesting to see if it shows up again. He basicly suggested to put the router on a different subnet.

So, the ICS will be 192.168.0.1

I will set the router WAN to 192.168.0.2, and connect the ICS to the WAN port of the router.
I will set the LAN to 192.168.10.1
I will configure the Asus router to assign a limited range of addresses for DHCP.
I will configure all other devices on the LAN to have static addresses.

I will post my milage as it goes...

 

[dboy]

Milage report:
So, this is just weird...

The link I posted to how to set the DHCP range for the ICS pc did not work, the registry posts did not exist in my WinXP installation. I googled the reason and it may be that this was a function in one of th XP beta versions that was skipped in the release version... so no way to restrict the dhcp range from the ICS.

So, I tried what Coldwizard suggested above, but regardless if I left automatic IP for WAN or used a static IP number for WAN, there is no routing through the router to the ICS and to the internet.

I then tried what Colin Taylor suggested, to set it in AP mode, and that works.

However, I experience frequent drops in connectivity. From a few seconds toa few minutes. Extremmely irritating when streaming sound or video.

It could be that there are IP conflicts, since I still need to assign static adresses to all devices on the net, at the same time as there is maybe/probably a defunct dhcp server running on the ICS.

The link to the GSM IP provider seem not to go down, my application has no way to restart itself, so if it drops the connection totally I need to reconnect manually, but that has not yet happened, so the link is stable. But, if I have ping.x.x.x.x -t running in a command window, I clearly se that my connectivity disapears, allthoug the link is up.

Really annoying.

 

[ColinTaylor]

The fact that you have said from the outset that you "have" to assign static IP addresses for anything to work suggests that there is something fundamentally wrong with your network setup

All your devices, including the ASUS, should be configured as DHCP clients. Only use static assignments for individual cases that absolutely can't use DHCP, like a domain controller. Creating lots of static PC's and playing around with the size of the DHCP pool is just going to add to the confusion.

Just to clarify;

When you tried coldwizard's suggested setup, you had the ICS PC connected directly to the WAN interface of the ASUS by cable. Yes?

With the ASUS's WAN interface setup as "Automatic IP" what WAN IP, DNS and gateway values did you get? Was the router connecting to the internet OK? i.e. it was getting NTP time OK and could ping google.com?