Simultaneous operation of LAN and WAN through a wi-fi router

Question

ASUS

I immediately apologize wildly for repeating the topic, but now I have all the data on the structure of our network in the hostel and have read dozens of pages on the features of my router.

Background: there is a wi-fi router ASUS RT-G32 B1 , a twisted pair with a hostel local network and the Internet is connected to it via WAN, but with such a connection only the internal network between our laptops and the global network is available.
When connected via LAN, respectively, there is an external local network, but without the Internet.

Problem: actually, a subject.

Internet Connection
Type: PPPoE
WAN IP Address: 10.100.95.254
Subnet Mask: 255.255.255.255
Gateway: 10.100.95.1
DNS Servers: 217.116.62.228 217.116.62.233
Connection status: Connected

Local network LAN
IP address: 172.25.75.1
Subnet mask: 255.255.0.0
Gateway: 172.25.0.1
Address assignment via DHCP.

I changed the firmware to 7.01.24 rev. B1 (7.12.10).

According to the link habrahabr.ru/qa/3815/ , the habrauser helped me a lot with setting up routing, for which many thanks to him, but so far our efforts have not been crowned with anything.

Well, I really want to set everything up!

Answer 1

ASUS RT-G32 B1? RaLink 3052? Install wive-ng-rtnl, you won't regret it. There it's all set up with half a kick.

Answer 2

Perhaps a problem with the routes? on the DIR300, I grabbed a lot of grief with the setup for my home provider.

Answer 3

MADSKILLZ option: dorm LAN cable to LAN1 port, patch cord (you may need a crossover, but unlikely) from LAN2 port to WAN.

Answer 4

Try firmware V3.0.2.1 Ru09.

Answer 5

1) When connecting via LAN, try to see where packets are lost going to the Internet. To do this, type "tracert habrahabr.ru" (for a Win host, or "traceroute habrahabr.ru" if you have linux). Look at what stage they are lost
2) Show your routing table on the host and on the router. On the host, you can type "route PRINT" for Win.
3) I can assume that the host does not have a default route that leads to the Internet. It should be something like:
ip route 0.0.0.0 0.0.0.0 10.100.95.1 metric 1
Such an entry will direct all packets for which there is no more specific entry in the routing table to the provider's gateway to the Internet (10.100.95.1 as I understand it)

Answer 6

>> And what addresses are used in the “external” local area? kekoz, today at 00:52
>172.25.xx.xx
>I configured the router's internal LAN in the same way thinking that something would come of it.
This is your main problem.
You need to connect via WAN.
Now I’m showing “on my fingers”: if the same addresses are used in your local area as in the external one (how, by the way, were you going to resolve ip-address conflicts?), then from the point of view of the router, access from your computers to the computer of the external local area does not need in routing. And this means that packets are sent only to LAN ports, they simply do not get to the WAN port. You can solve the problem in two ways:
1. proxy-arp. To all requests from an external locale like “What is the mac-address of the host 172.25.xxx.xxx (xxx.xxx is your locale)?” your router on the WAN port responds with “It's me!” Whether your piece of iron is able to do this, I don’t know, figure it out yourself.
2. ip-addresses in your network must be from another ip-space. But this gives rise to the following problem.
I'm showing you with my fingers again. Let's say you do 192.168.25.0/24 internally. From your host 192.168.25.5 you ping 172.25.25.25. The packet hits your router. The router sees that the packet is assigned to another network, it throws it out to the WAN port. There it falls on 172.25.25.25. He gives birth to a response to the ping. Packet from 172.25.25.25 to 192.168.25.25. And where will he go? How can hosts in the external LAN know that packets to 192.168.25.0/24 should be sent exactly to your router? And they don't know it. And therefore you will not receive answers from an external lokalka to yourself. Here again there are two solutions:
1. Make sure that the external local area knows about your network. If you are not the administrator of this very external locale, then the task is hardly solvable :) - you need to either raise the corresponding static route there, or some kind of routing protocol (at least RIP).
2. Packets from your network should look like they are from the outside network. This is already very simple - this is NAT. And this is your router for sure. That is exactly what you must do.