Rapberry PI Wifi Router

Prerequisite

For this guide, you will need

• A Raspberry Pi 3: It can work on previous generations but you will need a WiFi USB card plus eventually manually install drivers.
• Raspbian: This guide is written for Raspbian.

Install

$ sudo apt install hostapd dnsmasq

Configure Interface

dhcpcd

dhcpcd is the default DHCP client in Raspbian. You need to disable it for the wlan0 interface to avoid conflicts with the rest of the setup.

Edit file /etc/dhcpcd.conf an add the following line at the end

denyinterfaces wlan0

Warning: This must be above any interface lines you may have added

And restart dhcpcd using

$ sudo systemctl restart dhcpcd.service

Interface

The second step is to configure the interface with a static IP address.

Edit the file /etc/network/interfaces and replace the block related to wlan0 by

allow-hotplug wlan0  
iface wlan0 inet static  
    address 10.18.16.1
    netmask 255.255.255.0
    network 10.18.16.0
    broadcast 10.18.16.255
#   wpa-conf /etc/wpa_supplicant/wpa_supplicant.conf

And apply the configuration using

$ sudo ifdown wlan0
$ sudo ifup wlan0

Configure Access Point

Warning:

This page is a work in progress and is not completed. Important informations might be missing or wrong.

First create the default config file using

$ zcat /usr/share/doc/hostapd/examples/hostapd.conf.gz | sudo tee /etc/hostapd/hostapd.conf > /dev/null

Then edit the file and change the following

# AP netdevice name (without 'ap' postfix, i.e., wlan0 uses wlan0ap for
# management frames); ath0 for madwifi
interface=wlan0

# Driver interface type (hostap/wired/madwifi/test/none/nl80211/bsd);
# default: hostap). nl80211 is used with all Linux mac80211 drivers.
# Use driver=none if building hostapd as a standalone RADIUS server that does
# not control any wireless/wired driver.
driver=nl80211

# SSID to be used in IEEE 802.11 management frames
ssid=MyWiFiNetworkName

# Country code (ISO/IEC 3166-1). Used to set regulatory domain.
# Set as needed to indicate country in which device is operating.
# This can limit available channels and transmit power.
country_code=CH

# Enable IEEE 802.11d. This advertises the country_code and the set of allowed
# channels and transmit power levels based on the regulatory limits. The
# country_code setting must be configured with the correct country for
# IEEE 802.11d functions.
# (default: 0 = disabled)
ieee80211d=1

# Operation mode (a = IEEE 802.11a, b = IEEE 802.11b, g = IEEE 802.11g,
# ad = IEEE 802.11ad (60 GHz); a/g options are used with IEEE 802.11n, too, to
# specify band)
# Default: IEEE 802.11b
hw_mode=g

# Channel number (IEEE 802.11)
# (default: 0, i.e., not set)
# Please note that some drivers do not use this value from hostapd and the
# channel will need to be configured separately with iwconfig.
#
# If CONFIG_ACS build option is enabled, the channel can be selected
# automatically at run time by setting channel=acs_survey or channel=0, both of
# which will enable the ACS survey based algorithm.
channel=11

# Enable WPA. Setting this variable configures the AP to require WPA (either
# WPA-PSK or WPA-RADIUS/EAP based on other configuration). For WPA-PSK, either
# wpa_psk or wpa_passphrase must be set and wpa_key_mgmt must include WPA-PSK.
# Instead of wpa_psk / wpa_passphrase, wpa_psk_radius might suffice.
# For WPA-RADIUS/EAP, ieee8021x must be set (but without dynamic WEP keys),
# RADIUS authentication server must be configured, and WPA-EAP must be included
# in wpa_key_mgmt.
# This field is a bit field that can be used to enable WPA (IEEE 802.11i/D3.0)
# and/or WPA2 (full IEEE 802.11i/RSN):
# bit0 = WPA
# bit1 = IEEE 802.11i/RSN (WPA2) (dot11RSNAEnabled)
wpa=2

# WPA pre-shared keys for WPA-PSK. This can be either entered as a 256-bit
# secret in hex format (64 hex digits), wpa_psk, or as an ASCII passphrase
# (8..63 characters) that will be converted to PSK. This conversion uses SSID
# so the PSK changes when ASCII passphrase is used and the SSID is changed.
# wpa_psk (dot11RSNAConfigPSKValue)
# wpa_passphrase (dot11RSNAConfigPSKPassPhrase)
#wpa_psk=0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef
wpa_passphrase=MySecretWiFiNetworkKey

# Set of accepted key management algorithms (WPA-PSK, WPA-EAP, or both). The
# entries are separated with a space. WPA-PSK-SHA256 and WPA-EAP-SHA256 can be
# added to enable SHA256-based stronger algorithms.
# (dot11RSNAConfigAuthenticationSuitesTable)
wpa_key_mgmt=WPA-PSK-SHA256

# Set of accepted cipher suites (encryption algorithms) for pairwise keys
# (unicast packets). This is a space separated list of algorithms:
# CCMP = AES in Counter mode with CBC-MAC [RFC 3610, IEEE 802.11i/D7.0]
# TKIP = Temporal Key Integrity Protocol [IEEE 802.11i/D7.0]
# Group cipher suite (encryption algorithm for broadcast and multicast frames)
# is automatically selected based on this configuration. If only CCMP is
# allowed as the pairwise cipher, group cipher will also be CCMP. Otherwise,
# TKIP will be used as the group cipher.
# (dot11RSNAConfigPairwiseCiphersTable)
# Pairwise cipher for WPA (v1) (default: TKIP)
#wpa_pairwise=TKIP CCMP
# Pairwise cipher for RSN/WPA2 (default: use wpa_pairwise value)
rsn_pairwise=CCMP

Configure DHCP

Warning:

This page is a work in progress and is not completed. Important informations might be missing or wrong.

# Never forward plain names (without a dot or domain part)
domain-needed
# Never forward addresses in the non-routed address spaces.
bogus-priv

# If you want dnsmasq to listen for DHCP and DNS requests only on
# specified interfaces (and the loopback) give the name of the
# interface (eg eth0) here.
# Repeat the line for more than one interface.
interface=wlan0

# On systems which support it, dnsmasq binds the wildcard address,
# even when it is listening on only some interfaces. It then discards
# requests that it shouldn't reply to. This has the advantage of
# working even when interfaces come and go and change address. If you
# want dnsmasq to really bind only the interfaces it is listening on,
# uncomment this option. About the only time you may need this is when
# running another nameserver on the same machine.
bind-interfaces

# Uncomment this to enable the integrated DHCP server, you need
# to supply the range of addresses available for lease and optionally
# a lease time. If you have more than one network, you will need to
# repeat this for each network on which you want to supply DHCP
# service.
dhcp-range=10.18.16.10,10.18.16.250,24h

Static IP Address

# Always give the host with Ethernet address 11:22:33:44:55:66
# the name fred and IP address 192.168.0.60 and lease time 45 minutes
dhcp-host=11:22:33:44:55:66,fred,10.18.16.14,45m

To find the mac address look at file /var/lib/misc/dnsmasq.leases

Configure IP Routing

Warning:

This page is a work in progress and is not completed. Important informations might be missing or wrong.