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modeemi:pub:computer-networking-event-22052026

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Computer networking event (22 May 2026)

Hi! welcome to our workshop! Today we'd like to show a few things that you can do with computer networks!

1. How does the LAN works (single subnet)

  • Set up the static IP addresses
    • Device IP: 192.168.1.x/24 (each participant has number from 1 to 254)
    • Mask: 255.255.255.0
    • Gateway IP: 192.168.1.253
  • Open the wireshark
    • use an “arp || icmp” as in a filter (that will show only ARP and ping messages)
  • Ping the other people IPs
  • Take a look at the ARP table in computer
    • command “arp -a” in windows
    • command “arp -n” in linux (net-tools have to be installed)
Local area network (4 participants)

2. Set up the router with custom configuration

Set up following stuff:

  • Set up network IP addresses (IPv4)
    • First router - 10.1.1.0/24
    • Second router - 10.1.2.0/24
    • Third router - 10.1.3.0/24
  • Set up DNS server for AdGuard

3. Set up point to point VPN

  • Install wireguard in openwrt
  • Then set it up with helpful instructions from this page

4. Turn Chromebook into cursed router

  • we will find commands on the fly
    • ip route add
    • ip addr add
    • and others:D

Useful configurations

  1. VPN project - two sites
    • first with 10.1.1.0/24 network, VPN server
    • second with 10.1.2.0/24 network, VPN client
    • first has 10.1.3.1/30, second has 10.1.3.2/30

Server:

[Interface]
PrivateKey = yourPrivateKey
Address = 10.1.3.1/30
ListenPort = 51820
PostUp = ip route add 10.1.2.0/24 via 10.1.3.2

[Peer]
PublicKey = OtherpartyPublicKey
AllowedIPs = 10.1.2.0/24, 10.1.3.2/32

Client:

[Interface]
Address = 10.1.3.2/30
PrivateKey = yourPrivateKey
PostUp = ip route add 10.1.1.0/24 via 10.1.3.1

[Peer]
PublicKey = OtherPartyPublickey
Endpoint = publicIP:51820
AllowedIPs = 10.1.1.0/24, 10.1.3.1/32
PersistentKeepalive = 21

Useful commands

Generate private and public key for VPN server

wg genkey | tee privatekey | wg pubkey > publickey; cat publickey; cat privatekey
modeemi/pub/computer-networking-event-22052026.1779615232.txt.gz · Last modified: by niko