Hey r/networking,

I'm a high school student with no expertise or education in the field of networking. The only experience I have is installing our home router, some simple port forwarding in this router and some management of the DHCP addresses. Recently I was in charge of organizing a LAN event for my entire school (the kind of event where you organize tournaments in different games and compete to win "prizes") and we had about 40 or so participants.

I'd planned everything: switches, internet connection (the school network is protected by a firewall, but our IT department provided me with a "private line"), cables, power suppliers, the works. But there was one crucial thing I had not thought of: Sharing the internet connection throughout our network setup.

The internet line we'd been given, used a static IP to connect to the "private line". It was no problem for a single computer to connect, a simple static connection in the network interface and that was dealt with. Now, it wasn't a problem setting up a router either, to connect to a static IP. But what I hadn't thought of (and here comes the big BUT), was the limitations of DHCP connections the router could handle.

To make a long story short, we had 30-40 people connecting through 1 WRT54g-v5 router and I don't want to spoil anything, but this setup didn't work. The router was unable to handle the amount of clients, which caused it not only to frequently drop the packets of the clients but also caused the firmware to restart the hardware, due to sheer amount of stress. This router was connected to two different 20-slot switches and it also provided a wireless connection. In a quick turn of events, one of my friends was able to gather some 3 WRT160NL routers (a bit newer) and we setup it up so that 1 router would handle some connections and the main internet line (through static IP), while another router would serve as a stress reliever for the first, handling a bit of the connections (what I thought in theory, was that the first router would just see a BIG load from 1 DHCP address, the one coming from router 2 & 3 - in essence the router #2 and #3 served as a DHCP server and switch). This didn't work either, the routers were still overstressed.

We eventually had to settle for a "LAN (without internet) only" solution. Here we had a Windows machine connect as in the first slot to a switch, in miraculously enough, this provided a LAN connection to the rest of the following machines connecting to this same switch. What I think happened (and I'm only testing theories here) was that the Windows machine acted as an address host, meaning it had a lot more power in sharing the connections.

Now, I've thought about this and I came to think about setting up a dedicated box for handling the DHCP connections, a solution that my friend explained to me which he learned about in some introductory IT/networking course. It involves the DHCP Daemon (dhcpd) Linux program and two bridged network interfaces. 1 network interface would be setup to acquire the connection through the static IP and will then bridge this connection to the second network interface, which would be connected to a switch (containing about 20-30 slots).

In this solution the dedicated machine would serve as a DHCP server, sharing the internet connection that it receives through static IP to a large switch, through two network interfaces. We'll provide this machine with the adequate resources. As I said, we're handling about 30-40 people, so what system requirements would a machine like this need? Is this solution "easy" to carry out?

Again, I am a big noob with no knowledge about larger networking ideals, circumstances or setup "rules". I'm really confused and my knowledge stems only from small home networks (in which the router does all the work for me anyway). Thanks for reading this large wall of text, I hope you're able to help me in finding a solution (also, I apologize for improper grammar, jargon and other English associated mistakes. English is not my mother tongue and I've tried my best to formulate myself as clear as possible. To clarify: when I say network interface, I mean LAN adaptor, a network interface card)

tl;dr: tried setting up network for "bigger" event (30-40 people), failed, no internet, only LAN connection through switches, how can I set it up better for next time?