Reply
Northerner
Posts: 4
Registered: ‎01-10-2010
Accepted Solution

IP address? DHCP?

Here in UK I want to connect using WRT 350N through a Modem, AM200, a necessity in fact as the WRT has no phone line modem. Gone through manuals several times and failure to connect seems to be due to my incorrect setting of the IPs  or possibly DHCP capabilities though neither manual mentions these issues arising from two separate devices. 

I understand only one device should be serving DHCP. Is that correct? If so which is best to give that responsibility to ? Further on this, one of the devices asks me at the top of the particular page, if IP to be got automatically. I can't recall as writing which device. I get my addresses dynamically from the ISP but wonder if the ref in the said config is internal within these two devices in my network.

Both devices have  default IP of 192.168.1.1 and clearly this won't work so which device's address should I change and what to? Unless you advise me otherwise I would want the router, WRT350N, to remain as that and farm out IPs but the router will not be the first device on the Lan would that be a problem ?

If you have any other advice on configs for this arrangement tell me. I normally use combined devices and in effect bought the WRT by mistake because of the 'vagueness' of the adverts in this respect. 

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

Re: IP address? DHCP?

The AM200 is router with integrated modem. That's the main problem. I would recommend only to use a single router.

Two recommended alternatives:

1. set the AM200 into bridge mode and use the WRT for your internet connection. The problem is, however, that this may not be possible if your ISP uses PPPoA to connect to the internet. The WRT does not support PPPoA, only the AM200. I think some ISPs in the U.K. use PPPoA. If that's the case with your ISP then this alternative is no option for you. With the AM200 bridged the WRT handles all internet related functions. The WRT also hands out IP addresses into the LAN through its DHCP server.

2. use the AM200 as your internet gateway/router/modem and use the WRT as simple access point and ethernet switch. In that case all internet-related functions are on the AM200 only. The DHCP server is on the AM200. You would have to change the LAN IP address of the WRT from 192.168.1.1 to 192.168.1.2 and turn off the DHCP server on the WRT. Then connect one of the LAN ports of the WRT to your AM200. Do not use the internet port on the WRT.

There is a third alternative, but I highly recommend not to use it. Chaining routers is less then optimal and some people experience disconnects, instability and other probems with this kind of setup:

3. Leave the AM200 as router and on 192.168.1.1. Change the LAN IP address of the WRT from 192.168.1.1 to 192.168.2.1. Now connect the internet port of the WRT to the AM200. Now you are running two DHCP servers, one on the AM200 serving 192.168.1.* to the LAN side of the AM200 which is also the WAN/internet side of the WRT (i.e. the WRT gets its internet IP address from the DHCP server of the AM200). The other DHCP server is the DHCP server on the WRT which now serves 192.168.2.* addresses to anything connected wired or wireless to the WRT.

Again, I don't recommend no. 3. You have chained two routers. Everything is first routed on the WRT then on the AM200 (or vice versa). Both routers run NAT.

I would recommend no. 1 if possible (i.e. unless you must use PPPoA). If not no. 1 then no.2.
Northerner
Posts: 4
Registered: ‎01-10-2010

Re: IP address? DHCP?

 
Northerner
Posts: 4
Registered: ‎01-10-2010

Re: IP address? DHCP?

Thanks. Not one solution but three. Fact is just about all ISPs here in UK require PPoA. It is a matter of the ubiquity of British Telecoms as the provider of the DSLAMS, and phone line ADSL.  I will use solution "2" but not till tomorrow. I will label solution  as solved (hopefully) in due course.
Expert
Expert
Posts: 12,649
Registered: ‎07-16-2006

Re: IP address? DHCP?

O.K. I see. In that case alternative 2 is the best in my opinion. You use the AM as internet gateway router and the WRT as simple access point...
Klatch
Posts: 2,829
Registered: ‎09-07-2006

Re: IP address? DHCP?

- Connect the AM200 to the WRT on the Ethernet port.

- Change the ip address of the WRT to 192.168.1.2.

- Disable the DHCP on WRT.

- Disable NAT under Advance Routing.

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

Re: IP address? DHCP?

Klatch, it is necessary to repeat everything I have already explained before???

Moreover, do not disabled NAT on the advanced routing page. This setting won't make a difference as there is no routing and no NAT on the WRT when there is nothing connected to the internet port. Disabling NAT will only make it harder in case the WRT must be used as internet gateway again...
Northerner
Posts: 4
Registered: ‎01-10-2010

Re: IP address? DHCP?

I have done that, as advised by the first reply. The setup appears stable and fast so far. Thanks to all who have helped