What is the difference between "WAN" and "LAN" ports on a router

[Steve]

I am having difficulty adding a 2nd wireless access point to my
network. I have a resident D-link wireless router that serves as the
DHCP server for my entire network, with static IP address assignments
based on MAC address for all resident devices, and dynamic IP address
assignments in a restricted nonoverlapping range for new devices
appearing on the network. I have a DSL modem in its WAN port, and a
hub in one LAN port and specific dedicated devices in the other three
LAN ports. I need to add a "foreign" Linksys wireless router to my
network to support some development that will last for some months. I
believe the problems I'm seeing are caused by both routers trying to
be DHCP servers. When I connect a LAN port on the foreign router to a
port on my hub, sometimes the foreign router picks up an IP address
correctly as assigned by my main router, but more often not, and I
can't find the new router's configuration page anywhere (even after
resetting to factory defaults), either in my network's IP address
range nor in the common default ranges of 192.168.0.xxx or
192.168.1.xxx. The DSL modem also acts as a DHCP server and correctly
assigns an address to the WAN port on the main router, and the ranges
of those two DHCP servers do not overlap and seem to cause no
problems. But plugging in the foreign router rarely works, and
sometimes brings the whole network crashing down.

Reasoning that perhaps the difference between the WAN and LAN ports
would be that the WAN ports act as a DHCP client while the LAN ports
act as DHCP servers, I tried connecting the WAN port of the foreign
router to a port on the hub and thence to a LAN port on the main
router, with no success.

So my question really has two parts:

1) Give me a fish - how should I be connecting two wireless routers so
I can see and configure both?

2) Teach me to fish - explain the difference between WAN and LAN
ports, and how to configure a network with multiple DHCP servers.

Thanks in advance for any insights.

 

[Pegasus \(MVP\)]

I am having difficulty adding a 2nd wireless access point to my
network. I have a resident D-link wireless router that serves as the
DHCP server for my entire network, with static IP address assignments
based on MAC address for all resident devices, and dynamic IP address
assignments in a restricted nonoverlapping range for new devices
appearing on the network. I have a DSL modem in its WAN port, and a
hub in one LAN port and specific dedicated devices in the other three
LAN ports. I need to add a "foreign" Linksys wireless router to my
network to support some development that will last for some months. I
believe the problems I'm seeing are caused by both routers trying to
be DHCP servers. When I connect a LAN port on the foreign router to a
port on my hub, sometimes the foreign router picks up an IP address
correctly as assigned by my main router, but more often not, and I
can't find the new router's configuration page anywhere (even after
resetting to factory defaults), either in my network's IP address
range nor in the common default ranges of 192.168.0.xxx or
192.168.1.xxx. The DSL modem also acts as a DHCP server and correctly
assigns an address to the WAN port on the main router, and the ranges
of those two DHCP servers do not overlap and seem to cause no
problems. But plugging in the foreign router rarely works, and
sometimes brings the whole network crashing down.

Reasoning that perhaps the difference between the WAN and LAN ports
would be that the WAN ports act as a DHCP client while the LAN ports
act as DHCP servers, I tried connecting the WAN port of the foreign
router to a port on the hub and thence to a LAN port on the main
router, with no success.

So my question really has two parts:

1) Give me a fish - how should I be connecting two wireless routers so
I can see and configure both?

2) Teach me to fish - explain the difference between WAN and LAN
ports, and how to configure a network with multiple DHCP servers.

Thanks in advance for any insights.

Having two DHCP servers on the same LAN is bad news. Having
three is worse! You must disable the DHCP server function on all
but one device on any one subnet.

On a router the LAN port connects to all internal devices, usually
via a switch. If the router acts as a DHCP server then it will assign
IP addresses to all devices that ask for an address via the LAN port.

The WAN port connects to the Internet.

If you required more detailed advice about your setup then it would
make things easier if you attached a sketch.

 

[Tim Judd]

I am having difficulty adding a 2nd wireless access point to my
network. I have a resident D-link wireless router that serves as the
DHCP server for my entire network, with static IP address assignments
based on MAC address for all resident devices, and dynamic IP address
assignments in a restricted nonoverlapping range for new devices
appearing on the network. I have a DSL modem in its WAN port, and a
hub in one LAN port and specific dedicated devices in the other three
LAN ports. I need to add a "foreign" Linksys wireless router to my
network to support some development that will last for some months. I
believe the problems I'm seeing are caused by both routers trying to
be DHCP servers. When I connect a LAN port on the foreign router to a
port on my hub, sometimes the foreign router picks up an IP address
correctly as assigned by my main router, but more often not, and I
can't find the new router's configuration page anywhere (even after
resetting to factory defaults), either in my network's IP address
range nor in the common default ranges of 192.168.0.xxx or
192.168.1.xxx. The DSL modem also acts as a DHCP server and correctly
assigns an address to the WAN port on the main router, and the ranges
of those two DHCP servers do not overlap and seem to cause no
problems. But plugging in the foreign router rarely works, and
sometimes brings the whole network crashing down.

Reasoning that perhaps the difference between the WAN and LAN ports
would be that the WAN ports act as a DHCP client while the LAN ports
act as DHCP servers, I tried connecting the WAN port of the foreign
router to a port on the hub and thence to a LAN port on the main
router, with no success.

So my question really has two parts:

1) Give me a fish - how should I be connecting two wireless routers so
I can see and configure both?

2) Teach me to fish - explain the difference between WAN and LAN
ports, and how to configure a network with multiple DHCP servers.

Thanks in advance for any insights.

I believe you've tried this, but here's the topology you're talking about

Internet -> WAN link -> LAN link(s) -> Foreign router.

Foreign Router = WAN connects to Main LAN (sounds right)
LAN on Foreign will provide a DHCP scope outside of Main's DHCPs scope.

Machine A on Foreign LAN's ports will get (for example 192.168.20.x) and
route to 192.168.20.1. The Foreign router will route to the main router
[192.168.0.x)'s LAN and finally get to the internet.

A ROUTER blocks broadcast packets, which is what DHCP clients use to
obtain an address. (mMy addressing scope wouldn't work on your LAN
segment!)

You'll have to setup another subnet for that second router, or use a
bigger switch (switch will allow the DHCP broadcast packets).

good luck.