How to bridge two wired DD-WRT routers

I have one DD-WRT router (herein: 1st) connected to the Internet, working perfectly, with client PCs assigned static IP addresses.

Now I want to add another static client (herein: 2nd), but this time it's another DD-WRT router, not a PC.

That 2nd DD-WRT is intended to be a DHCP server, "fanning out" whatever is connected to it, such that the other (1st) router sees those client as coming from that single port/IP (say 192.168.14.31).

So far so good, but for some reason the clients that are connected through the 2nd router can't see the Internet.

If I connect a PC to that port assigning to it that static 192.168.14.31 address, it can access the Internet without any problem, so I know that the problem isn't in the first router. The problem is misconfiguration of the 2nd (client) DD-WRT router, as it simply doesn't know how to forward clients from its subnet (192.168.1.X) to the 1st router (192.168.14.1).

Using tracert I have been able to verify that this is indeed the problem. But I don't know what (and how), out of the zillion settings in DD-WRT, to change.

I tried changing the Operating Mode in Advanced Routing from Gateway to Router but while this seems in the right direction, it didn't solve the problem.

Any idea what I should be doing in that 2nd router to tell it to start forwarding packets from 192.168.1.x to 192.168.14.1?

UPDATE 1: I managed to telnet into the router and print the routing table:

Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
192.168.1.0     *               255.255.255.0   U     0      0        0 br0
192.168.14.0    *               255.255.255.0   U     0      0        0 vlan1
169.254.0.0     *               255.255.0.0     U     0      0        0 br0
127.0.0.0       *               255.0.0.0       U     0      0        0 lo
default         192.168.14.1    0.0.0.0         UG    0      0        0 vlan1

It's clear that the routing table is incorrect, but how do I change it on DD-WRT?

Also, I know what the WAN and LAN ports are, but what are br0 and vlan1? How do I correlate them to the WAN and LAN ports? (I think br0 is one of the LAN ports and vlan1 is the WAN port but I am not sure)

UPDATE 2: I found an option to print the routing table from within DD-WRT's web interface:

192.168.1.0   255.255.255.0   0.0.0.0        LAN & WLAN 
192.168.14.0  255.255.255.0   0.0.0.0        WAN 
169.254.0.0   255.255.0.0     0.0.0.0        LAN & WLAN 
0.0.0.0       0.0.0.0         192.168.14.1   WAN 

Which tells me that, according to DD-WRT:

• br0 == LAN & WLAN
• vlan1 == WAN (just as I thought)

Good to know. Now I need to solve this problem (I still have no clue): Make packets from the 192.168.1.x network reach the 192.168.14.1 gateway.

UPDATE 3: Insight. I think that the problem lies with the fact that the netmask for the 192.168.14.0 entry is not 255.255.0.0. The problem is, there is no way to change it… I tried adding an explicit entry in the Advanced Routing tab:

Select set number: WTF
Route Name: WTF
Metric: 0
Destination LAN NET: 192.168.14.0
Subnet Mask: 255.255.0.0
Gateway: 192.168.14.1
Interface: vlan0

But the routing table remains the same even after applying, saving and rebooting!!!

I am beginning to suspect that there is a bug in this DD-WRT v24-sp1 (07/27/08) std release.