Ubuntu wifi hostapd ap

Setting up a wireless-to-wireless router

When installing, setup the initial user to automatically log in.

Setup hostapd, port forwarding, haveged, and dnsmasq

Install and configure hostapd to automatically start on boot up using wlan0, and communicate on 802.11n, 2.4GHz (150 Mbps), with WPA2-Personal:

sudo apt-get -y install hostapd sudo nano /etc/default/hostapd

DAEMON_CONF="/etc/hostapd/hostapd.conf"

sudo nano /etc/hostapd/hostapd.conf

auth_algs=1 beacon_int=50 channel=3 country_code=US disassoc_low_ack=1 driver=nl80211 hw_mode=g ht_capab=[HT40+][HT40-][SHORT-GI-40][RX-STBC1] ieee80211d=1 ieee80211n=1 interface=wlan0 require_ht=0 rsn_pairwise=CCMP ssid=YOURSSID wmm_enabled=1 wpa=2 wpa_key_mgmt=WPA-PSK wpa_passphrase=YOURPASSPHASE

Replace the country_code, ssid, and wpa_passphrase with the applicable information. For some reason, a Windows 8.1 client (Qualcomm Atheros AR956x Wireless Network Adapter) would not connect when require_ht=1. Event Viewer noted «A response was not received from the router or access point.» However, this same client booted into Ubuntu worked fine, as well as Mac OS X Yosemite, iPhone, and a android smartphone.

Next, have port forwarding enabled automatically on boot up:

net.ipv4.ip_forward=1 net.ipv6.conf.all.forwarding=1

Next, have NAT traffic initiated on wlan0 forwarded to wlan1 enabled automatically on boot up:

iptables -t nat -A POSTROUTING -o wlan1 -j MASQUERADE iptables -A FORWARD -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT iptables -A FORWARD -i wlan0 -o wlan1 -j ACCEPT exit 0

Next, increase the default amount of entropy on your router and linux clients via haveged. When a linux operating system runs low on entropy (< 1000), it causes severe encrypted communcation latency (among other problems):

sudo apt-get -y install haveged

Next, install and configure dnsmasq for DHCP mapping IP addresses to MAC addresses:

sudo apt-get -y install dnsmasq sudo nano /etc/dnsmasq.conf

interface=wlan0 except-interface=wlan1 dhcp-range=10.0.0.2,10.0.0.14,12h

Note: One may want to setup DHCP reservations to bind a MAC address to a specific IP address (in the case of servers or clients you want to remote into by IP address) by adding to this file:

Where the «X»s are replaced with the MAC address, and both Y and Z with the relevant IP address numbers.

Configuring networking

One has a number of options for setting up networking. One may use the GUI driven NetworkManager for the managed interface and /etc/network/interfaces for access point. This has the benefit of being more user friendly. Another option is setting up both interfaces via /etc/network/interfaces. This has the benefit of reducing computer resources overhead.

Method 1: NetworkManager and /etc/network/interfaces

Connect wlan1 to the upstream router via NetworkManager (have «All users may connect to this network» checked). As well, it would be best to set the IP address statically so you may remote into this interface by IP address easily. It is recommended to setup x11vnc tunneled through SSH to easily administer the computer remotely.

Next, setup the wlan0 interface to have a static IP address, set to wireless master mode, and come up automatically on boot up via a terminal:

sudo nano /etc/network/interfaces

auto lo wlan0 iface lo inet loopback #access point iface wlan0 inet static address 10.0.0.1 netmask 255.255.255.240 gateway 10.0.0.1 dns-nameservers 192.168.1.1 wireless-mode Master

Next, set NetworkManager to ignore the wlan0 interface:

sudo nano /etc/NetworkManager/NetworkManager.conf

Ubuntu wifi hostapd ap unmanaged-devices=mac:XX:XX:XX:XX:XX:XX

Replace the «X»s with the MAC address for wlan0.

Considerations

• One may want to utilize a computer with two internal PCIe WiFi adapters, versus a USB WiFi dongle. This would maximize the speed of internal adapter-to-adapter communication, and avoid any potential USB overheat issues.
• One would want to avoid using devices with less developed WiFi drivers (ex. Belkin N300 Wireless USB Adapter F9L1002v1 050d:845a which uses staging driver r8712u) over more developed ones (ex. ath9k). In the case of the above device with r8712u, this is due to how lowering the transmission power of the adapter via the following terminal command is not yet developed:

iwconfig wlan0 txpower 14

Setting up a bridged wireless-to-ethernet router

Overview

This is an advanced, command line only setup for creating a bridged wireless router with Ubuntu Server. Here is the network diagram for this setup:

Note: This inkscape diagram network.svg is available for download from: More Actions > Attachments.

Prerequisites

• One gigabit ethernet switch.
• One USB drive with Ubuntu Server ISO setup for install (Verified with 7.10).
• A dedicated computer that will function as your router, with the following hardware:
  • One wireless NIC (ath0), that supports master mode. For more on this, please see here.
  • One ethernet NICs (eth0).
  • SSH
  • putty — remote console
  • WinSCP — remote file transfer

  Install Ubuntu Server

  Install Ubuntu Server Edition. One may choose the following options to install:

  [*] DNS server [*] OpenSSH server

  Update and upgrade Ubuntu:

  sudo apt-get update sudo apt-get dist-upgrade

  To install DNS server and SSH Server after an ubuntu installation use the command:

  Setup SSH

  Assuming that your ubuntu box is connected to your upstream router, you will need to find your IP address of your ubuntu box so you can connect with putty:

  On your windows machine install putty. Type in your ubuntu IP address into putty then connect. You can now cut and paste the following the commands. If you want to transfer files use WinSCP.

  Setup the network

  eth0 is the WAN interface (gateway) eth1 is the LAN interface ath0 is the wireless card br0 is the bridged connection of ath0 and eth1

  sudo apt-get install bridge-utils

  Then edit the network config:

  sudo nano /etc/network/interfaces

  # This file describes the network interfaces available on your system # and how to activate them. For more information, see interfaces(5). # The loopback network interface auto lo iface lo inet loopback #Gateway - auto eth0 iface eth0 inet dhcp pre-up iptables-restore < /etc/iptables.rules post-down iptables-save >/etc/iptables.rules #Wireless Setup auto ath0 iface ath0 inet manual wireless-mode master wireless-essid pivotpoint #Bridge interface auto br0 iface br0 inet static address 10.1.1.1 network 10.1.1.0 netmask 255.255.255.0 broadcast 10.1.1.255 bridge-ports eth1 ath0

  Setup firewall rules

  sudo iptables -t nat -A POSTROUTING -s 10.1.1.0/24 -o eth0 -j MASQUERADE sudo iptables -A FORWARD -s 10.1.1.0/24 -o eth0 -j ACCEPT sudo iptables -A FORWARD -d 10.1.1.0/24 -m conntrack --ctstate ESTABLISHED,RELATED -i eth0 -j ACCEPT

  sudo iptables -A INPUT -m conntrack --ctstate NEW -p tcp --dport 80 -j LOG --log-prefix "NEW_HTTP_CONN: "

  The above log will also appear in /var/log/messages, /var/log/syslog, and /var/log/kern.log.

  Save to /etc/iptables.rules via:

  sudo sh -c "iptables-save > /etc/iptables.rules"

  NOTE: This is a basic setup that only routes NAT packets. Please investigate further securing your firewall.

  Diagnostic tools

  Immediately allow the forwarding of packets. The configuration is not preserved on reboot but sets a flag in the kernel itself:

  echo 1 | sudo tee /proc/sys/net/ipv4/ip_forward

  Test the current setting of the kernel:

  cat /proc/sys/net/ipv4/ip_forward

  Note: The /proc directory is not on your hard drive but is present in the running kernel.

  Setup the DHCP server

  This will create a 10 machine DHCP server via a terminal:

  sudo apt-get install dhcp3-server

  sudo nano /etc/dhcp3/dhcpd.conf

  # Subnet for DHCP Clients subnet 10.1.1.0 netmask 255.255.255.0 option domain-name-servers 10.1.1.1; max-lease-time 7200; default-lease-time 600; range 10.1.1.50 10.1.1.60; option subnet-mask 255.255.255.0; option broadcast-address 10.1.1.255; option routers 10.1.1.1; >

  NOTE: If a DNS server (bind9) hasn’t been installed change «option domain-name-servers 10.1.1.1» to the IP address of the DNS server provided by your ISP. Optionally, one may use a public DNS server such as Google DNS: 8.8.8.8 or 8.8.4.4.

  You also need to edit the file /etc/default/dhcp in order to specify the interfaces dhcpd should listen to. By default it listens to eth0. We need to only have it listen to our local NIC (br0):

  sudo nano /etc/default/dhcp3-server

  Optional: Monitoring with darkstat

  sudo apt-get install darkstat

  Edit the configuration file:

  sudo nano /etc/darkstat/init.cfg

  # Turn this to yes when you have configured the options below. START_DARKSTAT=yes # Don't forget to read the man page. # You must set this option, else darkstat may not listen to # the interface you want INTERFACE="-i eth1" PORT="-p 8888" #BINDIP="-b 127.0.0.1" #LOCAL="-l 10.1.1.0/24" #FIP="-f 127.0.0.1" #DNS="-n" #SPY="--spy eth1"

  To see this point a browser to: http://10.1.1.1:8888

  Optional: Monitoring with saidar

  Saidar shows server usage:

  sudo apt-get install saidar

  Optional: Disabling IPv6

  Depending on your hardware, speed improvements may be found by disabling IPv6. For more on this, please see WebBrowsingSlowIPv6IPv4.

  Backup

  sudo su - cd / tar cvpjf backup.tar.bz2 --exclude=/proc --exclude=/media --exclude=/mnt --exclude=/dev --exclude=/lost+found --exclude=/backup.tar.bz2 --exclude=/tmp --exclude=/sys /

  You will then have a tar ball that is your server.

  External links

  WifiDocs/WirelessAccessPoint (последним исправлял пользователь 155 2015-05-10 12:05:12)

  The material on this wiki is available under a free license, see Copyright / License for details
  You can contribute to this wiki, see Wiki Guide for details

  Источник

  ExtremeGTX / Ubuntu_AP.md

  This error occurs because systemd-resolved is running and use this port. Particularly, I don’t want to change this behavior and just disabled dnsmasq DNS feature, so I simply changed the port adding to file /etc/dnsmasq.conf :
  port=5353

  Just in case someone else needs if found this tutorial.

  if you want dnsmasq to be your resolver, you can also follow the instructions here:
  https://computingforgeeks.com/install-and-configure-dnsmasq-on-ubuntu-18-04-lts/

  I have ubuntu 20.04 and I don’t know why keep getting «unknown interface wlan0»
  Anything I’m missing?

  [Unit] Description=dnsmasq - A lightweight DHCP and caching DNS server Requires=network.target Wants=nss-lookup.target network-online.target Before=nss-lookup.target After=network.target network-online.target [Service] Type=forking PIDFile=/run/dnsmasq/dnsmasq.pid ExecStartPre=/usr/sbin/dnsmasq --test ExecStart=/etc/init.d/dnsmasq systemd-exec ExecStartPost=/etc/init.d/dnsmasq systemd-start-resolvconf ExecStop=/etc/init.d/dnsmasq systemd-stop-resolvconf ExecReload=/bin/kill -HUP $MAINPID [Install] WantedBy=multi-user.target 

  wlan0 is the device name of the wireless card. The example was assuming Raspberry Pi hardware, and that should be the name of the built in wireless on a Raspberry by 3/4. The instructions have you edit a .yaml file in the /etc/netplan directory, and the device name is specified in that file.

  If you are getting and unknown interface wlan0, it is most likely because your wireless card has a different name, and you would have to put it’s correct name in the .yaml file.

  To find the name of your wireless card device, you could do this:

  In the output of that command you should look for «Wireless» in the description, and in that section, the logical name will be the device name you need. Unfortunately not all wireless card all supported, and it is still possible that lshw will not have a logical name for your device.

  Источник