Some configurations

Sometimes there are some things you want to change. Things like enabling peripherals like uart, spi or i2c or configuring a static IP address are all little things you need to change outside of the raspi-config tool.

This page lists some of these little things in random order.

A static IP address for the Raspberr yPi

Sometimes it's just easier to have a static IP address instead of a DHCP assigned one, it makes life easier if you have multiple Pi's that you want to address.

Lately, DHCPD5 was introduced making life a bit more complicated than it used to be.

Using /etc/network/interfaces

By default, all information for the network interfaces is documented in /etc/network/interfaces.

Just find part that addresses eth0, comment out any lines that say iface eth0 auto or iface eth0 dhcp and add the network addressing commands as below:

iface eth0 inet static
address 192.168.0.107
netmask 255.255.255.0
gateway 192.168.0.1

Of course you'll have to change the IP address and the address of the router to the ones applicable for the network you use. Check this using "ifconfig eth0" before changing this or check this on any PC connected to the network.

with DHCPD5

DHCPD5 complicates stuff a bit. It does not look at the /etc/network/interfaces file.

A static IP has to be defined in the /etc/dhcpcd.conf file.

Just add:

interface eth0
static ip_address=192.168.0.107
static routers=192.168.0.1
static domain_name_servers=192.168.0.1

at the end of the file and you're done.

Slow SSH login

The ssh deamon uses a reverse DN lookup in order to validate the ssh client's address.
If you are on a local network, it may be the case that there is no DNS lookup possible for your local IP addresses. This results in a (long) delay between the login and the password prompt.

Luckily there is an easy way to fix this.

In /etc/ssh/sshd_config, add a line with the text UseDNS no at the end. Now restart the service (service ssh reload) and your ssh connections will no longer suffer from the delay.

Wireless

The Raspberry 3 is equipped with a wireless network interface.

If you are using a graphical interface it's all clear on how to do this. Just move your mouse to the network icon in the status bar and do the right thing.

If you are using the command line interface, edit /etc/wpa_supplicant/wpa_supplicant.conf and add the following:

network={
    ssid="The_ESSID_from_earlier"
    psk="Your_wifi_password"
}

If you don't know the SSID of your network, use the command sudo iwlist wlan0 scan to get a list of all networks available. Grep on SSID to get only the lines with the SSID information.

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