2 routers 2 network 1 internet 2 DHCP

[DrW]

Hi,
I've been reading this and the oposite on the topic, and I would like to have a proper opinion from SmallNetBuilders on the topic.

My curent set up is

A netgear cbvg834g
NAT mode enable (ie set up as router)
LAN ip: 192.168.100.1
Subnet 255.255.255.0
Starting IP Address 192.168.100.10 / end .20
Mac filter: reserver ip : DIR-655 192.168.100.11 ethernet
DMZ host : 192.168.100.11
Respond to ping on wan


2 Dlink Dir-655 pluged on its WLAN to the Netgear
IP Address :192.168.100.11
Subnet Mask :255.255.255.0
Default Gateway :192.168.168.1
DHCP on



This set up has been working for a year or so,although I from time to time have to unglug the Dir-655.

My question is this: From a technical point of view , is there something wrong with this set up? Is there a way to optimise It?

I have to use the A netgear cbvg834g as it's the cable modem, usualy it is advised to turn off the dhcp from the second router. Not so great If you do not like the routing capacity of the first router or am I mistaken ?


Thank you for your advises

 

[coxhaus]

I guess if you are happy with the setup why change.

I have a couple of questions about your setup. Does the Dlink on the WLAN side receive a DHCP IP address from the Netgear router's DMZ? The Dlink is within the DHCP scope of the Netgear.

It is interesting that Dlink WLAN and LAN are within the same network and it works. I assume there is no bridge setting in the Dlink since it was not mentioned. Maybe the Dlink creates an automatic bridge in this case.

Why is the default gateway on the Dlink set to 192.168.168.1 a network which does not exist? I assume the Netgear has the correct default gateway 192.168.100.1 and you are overriding the correct default gateway with 192.168.168.1 on the Dlink.

To me if the DLink is providing DHCP to its clients with a default gateway which does not match the internet router then I would think they would not be able to get to the internet because they have the wrong gateway IP address. Would you check a client off of the Dlink and let me know what the default gateway IP address is of that client?

 

[DrW]

The Dlink get its ip 192.168.100.11 from the Netgear (DMZ or not)
Both router have there DHCP running but on different scope

The default gateway http://192.168.0.1 not 168.1 (mistake above) on the Dlink is the IP of the Netgear , the IP I can log in from a computer on the Dlink.

 

[coxhaus]

Ok. It sounds like you are running a normal double NAT. I try to avoid double NAT but it works.

 

[DrW]

Could you please , enlight me about the downsize of double NAT .

 

[coxhaus]

Double NAT can cause problems with some software. I ran a mail server at my house for 10 years before I retired and there were issues with double NAT. If you want to port forward or trigger ports for software double NAT is not going to be fun. I am sure there are other issues, I don’t double NAT.

 

[jlake]

When your hear about double NAT being a bad thing, it's because people don't clarify and say double NAT on the same subnet (same scope) is a bad thing.

Since your double NAT is on different scopes, it's not a bad thing.
If you ever need to do any port forwarding, all you have to do is google "double router port forwarding" and read the article on portforwarding.com.
Once you understand the concept that your LAN-to-WAN cascaded routers have an internal and an external IP address, it's very easy to do port forwarding on multiple nats.

For the typical home user, one NAT is almost always simpler/better and less of a headache.... especially for file sharing, printer sharing, and gaming.

Edit: I use one NAT 99 percent of the time because it's easier. Especially when you can use guest network to keep visitors off your LAN.