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# pi-ap: These scripts configure a Raspberry Pi into a wireless Access Point

# Source: https://github.com/f1linux/pi-ap

Version: 01.10.02

# License: GPL 3.0

# Script Author: Terrence Houlahan Linux & Network Engineer

# Contact: houlahan@F1Linux.com

# Linkedin: www.linkedin.com/in/terrencehoulahan

README CONTENTS:

1. ABOUT "pi-ap"
2. USE-CASES
3. COMPATIBILITY
4. FEATURES
5. LICENSE
6. HARDWARE REQUIREMENTS
7. INSTALLATION
8. CONNECTING TO AP
9. TROUBLESHOOTING
10. USEFUL LINKS: Wiki & YouTube Channel

1. ABOUT "pi-ap":

"pi-ap" is a series of bash scripts that automates configuration of below standardized packages to transform a PI into a wireless Access Point ("AP"):

• hostapd: Probably the most widely used package for creating an AP in Linux and a standard

• wpa_supplicant: Client Authentication

• dhcpcd: Interface management

• dnsmasq: DHCP for connecting AP clients: Assigns IPs and the DNS servers clients should use

Other host configuration is performed, but the foregoing are the key packages related to delivering the AP functionality

2. USE-CASES

pi-ap is NOT meant to replace enterprise class AP systems which offer beefier hardware and joined-up management interfaces for building or campus deployments. The obvious use cases for these scripts is:

• Dead-Spot Coverage: Individuals and small businesses with a few dead-spots in their WiFi coverage can use this solution

• Event Coverage: Connect a pi-ap to a long Ethernet cable out of a window into your back yard for hammock surfing :-)

• Network Training: An AP is a networking microcosm offering wide opportunities for teaching networking configuration & troubleshooting on inexpensive commodity hardware

3. COMPATIBILITY

These scripts have been tested on the following Pi models & OSs and found to work correctly:

• Pi 3B+: Raspbian Stretch (2019-04-08) and Buster (2019-07-10)

• Pi 4: Raspbian Buster (2019-07-10)

4. FEATURES

• No Subnetting Required: DHCP IP pool for connecting clients is automatically calculated from a single IP and mask you specify

• Auto Config of WiFi Regulatory Zone: This is derived from the Public IP you are NATing out from and ensures you cannot make an error setting it

• MAC Address Restriction: In addition to restricting by password you also have the ability to restrict by hardware address of connecting devices

• Centralized Package Management: Customize the package list by editing the list in "packages-list-install.txt"

• Modular Design: Configuration is broken down into scripts organized by taxonomy: ie FW, packages, Kernel, AP stuff, etc...

• Crypto uses Hardware Random Number Generator ("RNG"): Entropy generated via hardware RNG using rng-tools

5. LICENSE

Terrence Houlahan developed "pi-ap" and opensources it under the terms of the GPL 3.0 License that is distributed with my repo source files

6. HARDWARE REQUIREMENTS

Pi Case:

AVOID METAL CASES!!! If you wrap a metal case around your Pi it is going to cause Layer 1 problems by impeding the signal.

Probably worth trying a few different cases of differing materials to see which gives you the best result in respect to signal performance.

NON-POE:

A long Ethernet cable, a Pi and a power supply are minimum requirements.

HOWEVER: Using an AP implies covering an area the antenna(s) of the router cannot itself reach. At such a distance- probably greater than 40 feet- or any distance their is not a mains outlet to power the Pi, using a single Ethernet cable for both Data + Power becomes more interesting.

POE:

POE gear I have had success with- YMMV- with my Pi applications is:

• Ethernet Cable: A Tripp Lite Cat6 24 AWG Ethernet Cable is suggested (for most use cases). Amazon sells them in various lengths & colours

• POE Switch: ZyXEL 8-Port GS1900-8HP-GB0102F switch. Also found on Amazon. Lots of features for a reasonable price

• POE Hat or POE Splitter: Although most Pi vendors sell the POE Hat, POE Splitters will be found on Amazon.

I discuss POE gear and perform a cost vs. benefit analysis at below link for those considering a POE implementation for their pi-ap:

choosing-a-pi4-power-supply

7. INSTALLATION & CONFIGURATION:

Hardware Configuration:

• Connect the Pi's eth0 port to a DHCP-enabled port in a router configured with Internet connection or a switch connected to this router.

NOTE: You can connect a "*pi-ap" to some intermediate router but you will of course have to configure the routing so the Pi can reach the router with the Internet connection.

Software Configuration:

All the complex configuration is abstracted into a centralized variables file named "variables.sh". This file is sourced by all repo scripts. Edit this file in nano to modify default values and execute install.sh. All the other scripts are chained off of install.sh That it to achieve a working Pi AP

Either using a local or SSH connection to the Pi execute the following commands:

• a) git clone https://github.com/f1linux/pi-ap

• b) Change Default Pi Password! Open a terminal and execute sudo su - and passwd pi

• c) cd pi-ap

• d) nano variables.sh # Modify default variable values. Most default values can be kept but change "APWPA2PASSWD" and if default WiFi subnet in "IPV4IPWLAN0='192.168.0.1/28' exists on your LAN set to a different subnet"

• e) nano hostapd.accept # If variable "MACADDRACL" set to "1" then add MAC addresses of clients allowed to connect to pi-ap before executing script

• f) sudo ./install.sh # Execute the install script which will call all the other scripts in the repo.

• g) cd ..;rm -rf pi-ap # Optionally delete the repo after "install.sh" completes.

8. CONNECTING TO AP:

After setup completes, to connect to your new Pi Access Point:

• a) Find its SSID inWireless Networks and connect with the password you set in variable "APWPA2PASSWD" when modifying variables.sh

• ssh pi@192.168.0.1 # This is the default IP variable "IPV4IPWLAN0"

You're in.

9. TROUBLESHOOTING

A suggested non-exhausitive list of things to investigate if pi-ap broken:

• sudo ufw status: Check FW not disabled. Needs to be up or masquerading in NAT table breaks

• Non-Metallic: If using a case for your Pi, only use a NON-METALLIC one to avoid Layer 1 connectivity problems

• Physical Positioning: Is there anything that will impede or interfere with the radio?

• FW In Front of Pi Not Blocking: Look for restrictive rules on any FW's in front of the pi-ap

• ip addr list: Check interfaces are all up. wlan0 must be up to connect to AP. eth0 must be up for AP traffic to reach Internet

• sudo systemctl status hostapd.service: When hostapd is not happy, your AP will be down.

• sudo systemctl status wpa_supplicant.service: When wpa_supplicant is not happy, clients cannot connect to AP.

• cat /proc/sys/kernel/random/entropy_avail: Use this command to investigate insufficient entropy errors when checking wpa_supplicant status

• tail -fn 100 /var/log/syslog: Review syslog for any interesting errors to investigate

• No Clashing Subnets: Variable "IPV4IPWLAN0" in variables.sh is used to setup the AP interface & create IP pool to assign addresses to connecting clients. Ensure "IPV4IPWLAN0" does not clash with any existing subnets

10. USEFUL LINKS:

Pi-AP YouTube Channel: F1Linux

Pi-AP Wiki: Github

I think that about covers it. Not a lot really to do to configure a Pi into a working Access Point with this pile of scripts...

Terrence Houlahan, Linux & Network Engineer F1Linux.com

Linkedin: Terrence Houlahan