Configure Networking: Difference between revisions

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This page will assist you in setting up networking on Alpine Linux.
This page documents various networking options available in Alpine Linux and helps to configure your network using either [[#Network setup-scripts|Network setup-scripts]] or manually and to [[#Connectivity testing|test]] your Internet access.  
{{Note|You must be logged in as root in order to perform the actions on this page.}}


= Setting System Hostname =
Alpine Linux uses [[ifupdown-ng]] for managing its network configuration. For WiFi, the default wireless daemon [[Wi-Fi|wpa_supplicant]] and [[iwd]] are fully supported in Alpine Linux. For additional gui/tui networking tools refer [[NetworkManager]].
To set the system hostname:
{{Cmd|echo "shortname" > /etc/hostname}}


Then, to activate the change:
== Network setup-scripts ==
{{Cmd|hostname -F /etc/hostname}}


If you're using IPv6, you should also add the following special IPv6 addresses to your <code>/etc/hosts</code> file:
The following network related scripts are available from the {{pkg|alpine-conf}} package as part of [[Alpine setup scripts]].
<pre>::1            localhost ipv6-localhost ipv6-loopback
fe00::0        ipv6-localnet
ff00::0        ipv6-mcastprefix
ff02::1        ipv6-allnodes
ff02::2        ipv6-allrouters
ff02::3        ipv6-allhosts</pre>


{{Tip|If you're going to use automatic IP configuration, such as IPv4 DHCP or IPv6 Stateless Autoconfiguration, you can skip ahead to [[#Configuring_DNS|Configuring DNS]].  Otherwise, if you're going to use a static IPv4 or IPv6 address, continue below.}}
* <code>[[Alpine_setup_scripts#setup-hostname|setup-hostname]]</code>
* <code>[[#setup-interfaces|setup-interfaces]]</code>
* <code>[[Alpine_setup_scripts#setup-dns|setup-dns]]</code>
* <code>[[Alpine_setup_scripts#setup-proxy|setup-proxy]]</code>
* <code>[[Alpine_setup_scripts#setup-ntp|setup-ntp]]</code>


For a static IP configuration, it's common to also add the machine's hostname you just set (above) to the <code>/etc/hosts</code> file.
All the above utilities are interactive. When [[Installation|installing]] Alpine linux, the <code>setup-alpine</code> script calls all the above scripts to setup networking.  


Here's an IPv4 example:
== setup-interfaces ==
<pre>192.168.1.150  shortname.domain.com</pre>


And here's an IPv6 example:
To setup networking quickly use [[#setup-interfaces|setup-interfaces]] script. The script can be used to configure ethernet, wireless, bridge,bond and vlan interfaces and will satisfy most trivial configurations. Start the script by running the command: {{Cmd|# setup-interfaces}}
<pre>2001:470:ffff:ff::2  shortname.domain.com</pre>
Available interfaces are: eth0 wlan0.
Enter '?' for help on bridges, bonding and vlans.
Which one do you want to initialize? (or '?' or 'done') [eth0]


= Configuring DNS =
choose <code>eth0</code> for Ethernet or <code>wlan0</code> for wireless device, as appropriate.
{{Tip|'''For users of IPv4 DHCP:''' Please note that <code>/etc/resolv.conf</code> will be completely overwritten with any nameservers provided by DHCP.
If DHCP does not provide any nameservers, then <code>/etc/resolv.conf</code> will still be overwritten, but will not contain any nameservers!}}


For a static IP address and static nameservers, use one of the following examples.
if asked:
Ip address for eth0? (or 'dhcp', 'none', '?') [dhcp]


For IPv4 nameservers, edit your <code>/etc/resolv.conf</code> file to look like this:<br />
choose <code>dhcp</code>, if you are using dhcp.
The following example uses [http://en.wikipedia.org/wiki/Google_Public_DNS Google's Public DNS servers].
nameserver 8.8.8.8
nameserver 8.8.4.4


For IPv6 nameservers, edit your <code>/etc/resolv.conf</code> file to look like this:<br />
Now it will ask <code>Do you to do any manual network configuration? (y/n) [n]</code>
The following example uses [http://www.he.net/ Hurricane Electric's] public DNS server.
nameserver 2001:470:20::2
You can also use Hurricane Electric's public IPv4 DNS server:
nameserver 74.82.42.42


{{Tip|If you decide to use Hurricane Electric's nameserver, be aware that it is 'Google-whitelisted'. What does this mean?  It allows you access to many of Google's services via IPv6. (Just don't add other, non-whitelisted, nameservers to <code>/etc/resolv.conf</code> — ironically, such as Google's Public DNS Servers.) Read [http://www.google.com/intl/en/ipv6/ here] for more information.}}
In most cases, you can accept the default option '''n''' . Choosing '''y''' will open the {{Path|/etc/network/interfaces}} file for editing in [[BusyBox#vi| '''vi''' editor]] to proceed with manual network configuration.


= Enabling IPv6 (Optional) =
The above script configures [[Configure_Networking#Networking_service|Networking service]], starts the service and adds it to the boot run level.


If you use IPv6, do the following to enable IPv6 now and at each boot:
If your networking needs are more advanced, refer to the following detailed guide for manual network configuration.
{{Cmd|modprobe ipv6
echo "ipv6" >> /etc/modules}}


= Interface Configuration =
== Setting hostname ==


== Loopback Configuration (Required) ==
To set the system hostname:{{Cmd|# echo "shortname" > /etc/hostname}}
{{Note|The loopback configuration must appear first in <code>/etc/network/interfaces</code> to prevent networking issues.}}
To configure loopback, add the following to a new file <code>/etc/network/interfaces</code>:
<pre>auto lo
iface lo inet loopback</pre>


The above works to set up the IPv4 loopback address (127.0.0.1), and the IPv6 loopback address (<code>::1</code>) — if you enabled IPv6.
Then, to activate the change: {{Cmd|# hostname -F /etc/hostname}}


== Wireless Configuration ==
If you're using IPv6, you should also add the following special IPv6 addresses to your {{path|/etc/hosts}} file:{{cat|/etc/hosts|...
::1            localhost ipv6-localhost ipv6-loopback
fe00::0        ipv6-localnet
ff00::0        ipv6-mcastprefix
ff02::1        ipv6-allnodes
ff02::2        ipv6-allrouters
ff02::3        ipv6-allhosts
}}


See [[Connecting to a wireless access point]].
{{Tip|If you're going to use automatic IP configuration, such as IPv4 DHCP or IPv6 Stateless Autoconfiguration, you can skip ahead to [[#Configuring_DNS|Configuring DNS]].  Otherwise, if you're going to use a static IPv4 or IPv6 address, continue below.}}


== Ethernet Configuration ==
For a static IP configuration, it's common to also add the machine's hostname you just set (above) to the {{path|/etc/hosts}} file.
For the following Ethernet configuration examples, we will assume that you are using Ethernet device <code>eth0</code>.


=== Initial Configuration ===
Here's an IPv4 example:{{cat|/etc/hosts|...
Add the following to the file <code>/etc/network/interfaces</code>, above any IP configuration for <code>eth0</code>:
192.168.1.150  shortname.domain.com
<pre>auto eth0</pre>
...
}}


=== IPv4 DHCP Configuration ===
And here's an IPv6 example:{{cat|/etc/hosts|...
Add the following to the file <code>/etc/network/interfaces</code>, below the <code>auto eth0</code> definition:
2001:470:ffff:ff::2  shortname.domain.com
<pre>iface eth0 inet dhcp</pre>
...
By default, the busybox DHCP client (udhcpc) requests a static set of options from the DHCP server. If you need to extend this set, you can do so by setting some additional command line options for the DHCP client, via the <code>udhcpc_opts</code> in your interface configuration. The following example requests
}}
<code>domain-search</code> option:
<pre>iface eth0 inet dhcp
    udhcpc_opts -O search</pre>
For a complete list of command line options for udhcpc, see [https://busybox.net/downloads/BusyBox.html#udhcpc this document].


=== IPv4 Static Address Configuration ===
== Configuring DNS ==
Add the following to the file <code>/etc/network/interfaces</code>, below the <code>auto eth0</code> definition:


<pre>iface eth0 inet static
{{Tip|'''For users of IPv4 DHCP:''' Please note that {{path|/etc/resolv.conf}} will be completely overwritten with any nameservers provided by DHCP.
        address 192.168.1.150
If DHCP does not provide any nameservers, then {{path|/etc/resolv.conf}} will still be overwritten, but will not contain any nameservers!}}
        netmask 255.255.255.0
        gateway 192.168.1.1</pre>


Since Alpine 3.13 (and only if you have <code>ifupdown-ng</code> installed) must be:
For a static IP address and static nameservers, use one of the following examples.


<pre>iface eth0 inet static
For IPv4 nameservers, edit your {{path|/etc/resolv.conf}} file to look like this:<br />
        address 192.168.1.150/24
The following example uses [https://en.wikipedia.org/wiki/Google_Public_DNS Google's Public DNS servers].
        gateway 192.168.1.1</pre>
{{cat|/etc/resolv.conf|nameserver 8.8.8.8
nameserver 8.8.4.4
}}


For IPv6 nameservers, edit your {{path|/etc/resolv.conf}} file to look like this:<br />
The following example uses [https://www.he.net/ Hurricane Electric's] public DNS server.
{{cat|/etc/resolv.conf|nameserver 2001:470:20::2}}
You can also use Hurricane Electric's public IPv4 DNS server:
{{cat|/etc/resolv.conf|nameserver 74.82.42.42}}


==== Additional IP addresses ====
{{Tip|If you decide to use Hurricane Electric's nameserver, be aware that it is 'Google-whitelisted'. What does this mean?  It allows you access to many of Google's services via IPv6. (Just don't add other, non-whitelisted, nameservers to {{path|/etc/resolv.conf}} — ironically, such as Google's Public DNS Servers.) Read [https://www.google.com/intl/en/ipv6/ here] for more information.}}


<pre>iface eth0 inet static
== Interface configuration ==
        address 192.168.1.150
        netmask 255.255.255.0


iface eth0 inet static
=== Loopback configuration  ===
        address 192.168.1.151/24
{{Warning|Loopback configuration is mandatory and must appear first in {{path|/etc/network/interfaces}} to prevent networking issues.}}
</pre>
To configure loopback, add the following to the file {{path|/etc/network/interfaces}}: {{cat|/etc/network/interfaces|auto lo
iface lo inet loopback
}}
The above works to set up the IPv4 loopback address (127.0.0.1), and the IPv6 loopback address (<code>::1</code>) — if you enabled IPv6.


Since Alpine 3.13 (and only if you have <code>ifupdown-ng</code> installed) must be:
=== Wireless configuration ===
{{Main|Wi-Fi}}
For manual interface configuration as explained in this page, <code>eth0</code> can be substituted by the appropriate wireless interface i.e <code>wlan0</code>.


<pre>iface eth0 inet static
=== Ethernet configuration ===
        address 192.168.1.150/24
        gateway 192.168.1.1


iface eth0 inet static
For the following Ethernet configuration examples, we will assume that you are using Ethernet device <code>eth0</code>.
        address 192.168.1.151/24
</pre>


=== IPv6 DHCP Configuration ===
==== DHCP configuration ====
Alpine's use of ifupdown-ng supports three DHCP clients: udhcpc, dhclient, and dhcpcd. Of these, only dhcpcd can interact with both DHCP and DHCPv6 from the same process, which ifupdown-ng requires. Thus the IPv4 DHCP configuration given above will also result in the use of DHCPv6, but only if you install the dhcpcd package. (The ifupdown-ng scripts prioritize dhclient over udhcpc, and they prioritize dhcpcd over dhclient; see <code>/usr/libexec/ifupdown-ng/dhcp</code>.)


=== IPv6 Stateless Autoconfiguration ===
The DHCP configuration with Busybox ifupdown syntax is as follows:{{cat|/etc/network/interfaces|...
Add the following to the file <code>/etc/network/interfaces</code>, below the <code>auto eth0</code> definition:
auto eth0
<pre>iface eth0 inet6 auto</pre>
iface eth0 inet dhcp}}


=== IPv6 Static Address Configuration ===
By default, the busybox DHCP client (udhcpc) requests a static set of options from the DHCP server. If you need to extend this set, you can do so by setting some additional command line options for the DHCP client, via the <code>udhcpc_opts</code> in your interface configuration. The following example requests
Add the following to the file <code>/etc/network/interfaces</code>, below the <code>auto eth0</code> definition:
<code>domain-search</code> option:
{{cat|/etc/network/interfaces|...
auto eth0
iface eth0 inet dhcp
    udhcpc_opts -O search}}
For a complete list of command line options for udhcpc, see [https://busybox.net/downloads/BusyBox.html#udhcpc this document].


<pre>iface eth0 inet6 static
With [[ifupdown-ng]], IPv4 DHCP configuration given on this page will also result in the use of DHCPv6, if {{pkg|dhcpcd}} is installed as dhcpcd can interact with both DHCPv4 and DHCPv6 from the same process.
        address 2001:470:ffff:ff::2
        netmask 64
        gateway 2001:470:ffff:ff::1
        pre-up echo 0 > /proc/sys/net/ipv6/conf/eth0/accept_ra</pre>


Since Alpine Linux 3.13 (and only if you have <code>ifupdown-ng</code> installed) must be as:
A basic configuration for a desktop computer using the ifupdown-ng syntax appears as follows:{{cat|/etc/network/interfaces|...
 
auto eth0
<pre>iface eth0 inet6 static
iface eth0
        address 2001:470:ffff:ff::2/64
    use dhcp}}
        gateway 2001:470:ffff:ff::1
        pre-up echo 0 > /proc/sys/net/ipv6/conf/eth0/accept_ra</pre>


== Example: Dual-Stack Configuration ==
All further configuration below assumes ifupdown-ng being used, unless stated otherwise.


This example shows a dual-stack configuration.
===== IPv6 stateless autoconfiguration =====
 
<pre>auto lo
iface lo inet loopback


With IPv6, stateless auto-configuration is typically used to configure network interfaces. If you are not interested in using IPv4 at all, you can simply use the ipv6-ra executor to ensure that an interface is configured to accept IPv6 RA advertisements:{{cat|/etc/network/interfaces|...
auto eth0
auto eth0
iface eth0
    use ipv6-ra}}


iface eth0 inet static
==== Static address configuration ====
        address 192.168.1.150
      netmask 255.255.255.0
        gateway 192.168.1.1


iface eth0 inet6 static
{{Note| If [[ifupdown-ng]] is not available/used, use {{ic|iface eth0 inet static}} instead of {{ic|iface eth0}} and use below address format for IPv4 instead of '''203.0.113.2/24 ''' :{{Cat|/etc/network/interfaces|address 203.0.113.2
        address 2001:470:ffff:ff::2
netmask 255.255.255.0}}}}
        netmask 64
        gateway 2001:470:ffff:ff::1
        pre-up echo 0 > /proc/sys/net/ipv6/conf/eth0/accept_ra</pre>


Take care since Alpine 3.13 (and only if you have <code>ifupdown-ng</code> installed) must be as:
Add the following to the file {{path|/etc/network/interfaces}}: {{cat|/etc/network/interfaces|...
auto eth0
iface eth0
    address 203.0.113.2/24
    gateway 203.0.113.1}}


<pre>auto lo
===== Multiple address =====
iface lo inet loopback


{{cat|/etc/network/interfaces|...
auto eth0
auto eth0
iface eth0
    address 203.0.113.2/24
    address 203.0.113.3/24
    address 203.0.113.4/24
    gateway 203.0.113.1}}


iface eth0 inet static
=====  Dual-stack configuration =====
        address 192.168.1.150/24
        gateway 192.168.1.1


iface eth0 inet6 static
This example shows a dual-stack configuration. {{cat|/etc/network/interfaces|...
        address 2001:470:ffff:ff::2/64
auto eth0
        gateway 2001:470:ffff:ff::1
iface eth0
        pre-up echo 0 > /proc/sys/net/ipv6/conf/eth0/accept_ra</pre>
    address 203.0.113.2/24
 
    address 203.0.113.3/24
= Firewalling with iptables and ip6tables =
    address 203.0.113.4/24
 
    gateway 203.0.113.1
See also: [[Alpine Wall]] - [[How-To Alpine Wall]] - [[Alpine Wall User's Guide]]
 
== Install iptables/ip6tables ==
* To install iptables:
: {{Cmd|apk add iptables}}


* To install ip6tables:
    address 2001:db8:1000:2::2/64
: {{Cmd|apk add ip6tables}}
    address 2001:db8:1000:2::3/64
    address 2001:db8:1000:2::4/64
    gateway 2001:db8:1000:2::1}}


* To install the man pages for iptables and ip6tables:
== Networking service ==
: {{Cmd|apk add iptables-doc}}


== Configure iptables/ip6tables ==
Changes made to {{path|/etc/network/interfaces}} can be activated by running: {{Cmd|# rc-service networking restart}}
To '''start''' (or '''restart''') the networking service: {{Cmd|# rc-service networking --quiet start &}}
To add networking service so that it starts on boot: {{Cmd|# rc-update add networking boot}}


== Firewall==


== Save Firewall Rules ==
Alpine Linux provides multiple firewall software. Some of the prominent ones are listed below:
* [https://git.alpinelinux.org/awall/about/ Alpine Wall User's Guide]
* [[Iptables]]
* [[nftables]]
* [[Uncomplicated Firewall]]


=== For iptables ===
== Troubleshooting ==
# Set iptables to start on reboot
#* {{ Cmd| rc-update add iptables }}
# Write the firewall rules to disk
#* {{ Cmd| /etc/init.d/iptables save}}
# If you use Alpine Local Backup:
<!-- Not needed on Alpine > 2.3
## Add the firewall rules to Alpine Local Backup
##* {{ Cmd| lbu add /var/lib/iptables/rules-save }}
-->
## Save the configuration
##* {{ Cmd| lbu ci }}


=== For ip6tables ===
=== Connectivity testing ===
# Set ip6tables to start on reboot
#* {{ Cmd| rc-update add ip6tables }}
# Write the firewall rules to disk
#* {{ Cmd| /etc/init.d/ip6tables save}}
# If you use Alpine Local Backup:
<!-- Not needed on Alpine > 2.3
## Add the firewall rules to Alpine Local Backup
##* {{ Cmd| lbu add /var/lib/ip6tables/rules-save }}
-->
## Save the configuration
##* {{ Cmd| lbu ci }}


= Activating Changes and Testing Connectivity =
Test if networking is configured properly by attempting to ping out:
Changes made to <code>/etc/network/interfaces</code> can be activated by running:
{{Cmd|<nowiki>$ ping www.google.com
{{Cmd|/etc/init.d/networking restart}}
PING www.l.google.com (74.125.47.103) 56(84) bytes of data.
If you did not get any errors, you can now test that networking is configured properly by attempting to ping out:
{{Cmd|ping www.google.com}}
<pre>PING www.l.google.com (74.125.47.103) 56(84) bytes of data.
64 bytes from yw-in-f103.1e100.net (74.125.47.103): icmp_seq=1 ttl=48 time=58.5 ms
64 bytes from yw-in-f103.1e100.net (74.125.47.103): icmp_seq=1 ttl=48 time=58.5 ms
64 bytes from yw-in-f103.1e100.net (74.125.47.103): icmp_seq=2 ttl=48 time=56.4 ms
64 bytes from yw-in-f103.1e100.net (74.125.47.103): icmp_seq=2 ttl=48 time=56.4 ms
Line 234: Line 198:
--- www.l.google.com ping statistics ---
--- www.l.google.com ping statistics ---
4 packets transmitted, 4 received, 0% packet loss, time 3007ms
4 packets transmitted, 4 received, 0% packet loss, time 3007ms
rtt min/avg/max/mdev = 56.411/58.069/60.256/1.501 ms</pre>
rtt min/avg/max/mdev = 56.411/58.069/60.256/1.501 ms
</nowiki>}}


For an IPv6 traceroute (<code>traceroute6</code>), you will first need to install the <code>iputils</code> package:
For an IPv6 traceroute run <code>traceroute6</code>:
{{Cmd|apk add iputils}}
{{Cmd|$ traceroute6 ipv6.google.com
 
traceroute to ipv6.l.google.com (2001:4860:8009::67) from 2001:470:ffff:ff::2, 30 hops max, 16 byte packets
Then run <code>traceroute6</code>:
{{Cmd|traceroute6 ipv6.google.com}}
<pre>traceroute to ipv6.l.google.com (2001:4860:8009::67) from 2001:470:ffff:ff::2, 30 hops max, 16 byte packets
  1  2001:470:ffff:ff::1 (2001:470:ffff:ff::1)  3.49 ms  0.62 ms  0.607 ms
  1  2001:470:ffff:ff::1 (2001:470:ffff:ff::1)  3.49 ms  0.62 ms  0.607 ms
  2  *  *  *
  2  *  *  *
Line 250: Line 212:
  7  2001:4860::2:0:a7 (2001:4860::2:0:a7)  101.754 ms  100.475 ms  100.512 ms
  7  2001:4860::2:0:a7 (2001:4860::2:0:a7)  101.754 ms  100.475 ms  100.512 ms
  8  2001:4860:0:1::c3 (2001:4860:0:1::c3)  99.272 ms  111.989 ms  99.835 ms
  8  2001:4860:0:1::c3 (2001:4860:0:1::c3)  99.272 ms  111.989 ms  99.835 ms
  9  yw-in-x67.1e100.net (2001:4860:8009::67)  101.545 ms  109.675 ms  99.431 ms</pre>
  9  yw-in-x67.1e100.net (2001:4860:8009::67)  101.545 ms  109.675 ms  99.431 ms
 
}}
= Additional Utilities =
 
== iproute2 ==
 
You may wish to install the 'iproute2' package (note that this will also install iptables if not yet installed)
 
{{Cmd|apk add iproute2}}


This provides the 'ss' command which is IMHO a 'better' version of netstat.
=== iproute2 ===


Show listening tcp ports:
Install the {{pkg|iproute2}} package which provides the 'ss' command which is an alternate to netstat.: {{Cmd|# apk add iproute2}}
{{Cmd|ss -tl}}


Show listening tcp ports and associated processes:
Show listening tcp ports:{{Cmd|$ ss -tl}}
{{Cmd|ss -ptl}}
Show listening tcp ports and associated processes:{{Cmd|$ ss -ptl}}
Show listening and established tcp connections:{{Cmd|$ ss -ta}}
Show socket usage summary:{{Cmd|$ ss -s}}
Show more options:{{Cmd|$ ss -h}}


Show listening and established tcp connections:
=== drill ===
{{Cmd|ss -ta}}


Show socket usage summary:
Install {{pkg|drill}} (it will also install the 'ldns' package) which is a superior replacement for nslookup and dig etc: {{Cmd|# apk add drill}}
{{Cmd|ss -s}}


Show more options:
Then use it as you would for dig: {{Cmd|$ drill alpinelinux.org @8.8.8.8}}
{{Cmd|ss -h}}
To perform a reverse lookup (get a name from an IP) use the following syntax: {{Cmd|$ drill -x 8.8.8.8 @208.67.222.222}}


== drill ==
=== Missing interface ===  


You may also wish to install 'drill' (it will also install the 'ldns' package) which is a superior (IMHO) replacement for nslookup and dig etc:
To list your available network interfaces use the commands {{ic|ip link}} or {{ic|ip a}}. Refer to [[Wi-Fi#Troubleshooting|Wifi troubleshooting]] page for issues related to wireless interfaces. If nothing works, you may have to use an alternate interface (e.g. a usb to ethernet adapter).


{{Cmd|apk add drill}}
== See also ==
 
Then use it as you would for dig:
 
{{Cmd|drill alpinelinux.org @8.8.8.8}}
 
To perform a reverse lookup (get a name from an IP) use the following syntax:
 
{{Cmd|drill -x 8.8.8.8 @208.67.222.222}}
 
= Related articles =


You may also wish to review the following network related articles:
You may also wish to review the following network related articles:
 
* [[Ifupdown-ng|Ifupdown-ng]] Basic networking Device Manager in Alpine Linux
[[Vlan|VLAN setup]]
* [[NetworkManager]] - Alternate Front-end to Networking
 
* [[VLAN|VLAN setup]]
[[Bonding|Bonding setup]]
* [[Bonding|Bonding setup]]
 
* [[Bridge|Network bridge setup]]
[[Bridge|Network bridge setup]]
* [[udhcpc|udhcpc configuration]]
 
* [[Wifi#wpa_supplicant|wpa_supplicant]] - Default wifi daemon
[[udhcpc|udhcpc configuration]]
* [[Iwd|iwd]] - An alternate wifi daemon
 


[[Category:Networking]]
[[Category:Networking]]

Latest revision as of 06:17, 22 March 2025

This page documents various networking options available in Alpine Linux and helps to configure your network using either Network setup-scripts or manually and to test your Internet access.

Alpine Linux uses ifupdown-ng for managing its network configuration. For WiFi, the default wireless daemon wpa_supplicant and iwd are fully supported in Alpine Linux. For additional gui/tui networking tools refer NetworkManager.

Network setup-scripts

The following network related scripts are available from the alpine-conf package as part of Alpine setup scripts.

All the above utilities are interactive. When installing Alpine linux, the setup-alpine script calls all the above scripts to setup networking.

setup-interfaces

To setup networking quickly use setup-interfaces script. The script can be used to configure ethernet, wireless, bridge,bond and vlan interfaces and will satisfy most trivial configurations. Start the script by running the command:

# setup-interfaces

Available interfaces are: eth0 wlan0.
Enter '?' for help on bridges, bonding and vlans.
Which one do you want to initialize? (or '?' or 'done') [eth0]

choose eth0 for Ethernet or wlan0 for wireless device, as appropriate.

if asked: 

Ip address for eth0? (or 'dhcp', 'none', '?') [dhcp]

choose dhcp, if you are using dhcp.

Now it will ask Do you to do any manual network configuration? (y/n) [n]

In most cases, you can accept the default option n . Choosing y will open the /etc/network/interfaces file for editing in vi editor to proceed with manual network configuration.

The above script configures Networking service, starts the service and adds it to the boot run level.

If your networking needs are more advanced, refer to the following detailed guide for manual network configuration.

Setting hostname

To set the system hostname:

# echo "shortname" > /etc/hostname

Then, to activate the change:

# hostname -F /etc/hostname

If you're using IPv6, you should also add the following special IPv6 addresses to your /etc/hosts file:

Contents of /etc/hosts

... ::1 localhost ipv6-localhost ipv6-loopback fe00::0 ipv6-localnet ff00::0 ipv6-mcastprefix ff02::1 ipv6-allnodes ff02::2 ipv6-allrouters ff02::3 ipv6-allhosts
Tip: If you're going to use automatic IP configuration, such as IPv4 DHCP or IPv6 Stateless Autoconfiguration, you can skip ahead to Configuring DNS. Otherwise, if you're going to use a static IPv4 or IPv6 address, continue below.

For a static IP configuration, it's common to also add the machine's hostname you just set (above) to the /etc/hosts file.

Here's an IPv4 example:

Contents of /etc/hosts

... 192.168.1.150 shortname.domain.com ...

And here's an IPv6 example:

Contents of /etc/hosts

... 2001:470:ffff:ff::2 shortname.domain.com ...

Configuring DNS

Tip: For users of IPv4 DHCP: Please note that /etc/resolv.conf will be completely overwritten with any nameservers provided by DHCP. If DHCP does not provide any nameservers, then /etc/resolv.conf will still be overwritten, but will not contain any nameservers!

For a static IP address and static nameservers, use one of the following examples.

For IPv4 nameservers, edit your /etc/resolv.conf file to look like this:
The following example uses Google's Public DNS servers.

Contents of /etc/resolv.conf

nameserver 8.8.8.8 nameserver 8.8.4.4

For IPv6 nameservers, edit your /etc/resolv.conf file to look like this:
The following example uses Hurricane Electric's public DNS server.

Contents of /etc/resolv.conf

nameserver 2001:470:20::2

You can also use Hurricane Electric's public IPv4 DNS server:

Contents of /etc/resolv.conf

nameserver 74.82.42.42
Tip: If you decide to use Hurricane Electric's nameserver, be aware that it is 'Google-whitelisted'. What does this mean? It allows you access to many of Google's services via IPv6. (Just don't add other, non-whitelisted, nameservers to /etc/resolv.conf — ironically, such as Google's Public DNS Servers.) Read here for more information.

Interface configuration

Loopback configuration

Warning: Loopback configuration is mandatory and must appear first in /etc/network/interfaces to prevent networking issues.


To configure loopback, add the following to the file /etc/network/interfaces:

Contents of /etc/network/interfaces

auto lo iface lo inet loopback

The above works to set up the IPv4 loopback address (127.0.0.1), and the IPv6 loopback address (::1) — if you enabled IPv6.

Wireless configuration

Main article: Wi-Fi

For manual interface configuration as explained in this page, eth0 can be substituted by the appropriate wireless interface i.e wlan0.

Ethernet configuration

For the following Ethernet configuration examples, we will assume that you are using Ethernet device eth0.

DHCP configuration

The DHCP configuration with Busybox ifupdown syntax is as follows:

Contents of /etc/network/interfaces

... auto eth0 iface eth0 inet dhcp

By default, the busybox DHCP client (udhcpc) requests a static set of options from the DHCP server. If you need to extend this set, you can do so by setting some additional command line options for the DHCP client, via the udhcpc_opts in your interface configuration. The following example requests domain-search option:

Contents of /etc/network/interfaces

... auto eth0 iface eth0 inet dhcp udhcpc_opts -O search

For a complete list of command line options for udhcpc, see this document.

With ifupdown-ng, IPv4 DHCP configuration given on this page will also result in the use of DHCPv6, if dhcpcd is installed as dhcpcd can interact with both DHCPv4 and DHCPv6 from the same process.

A basic configuration for a desktop computer using the ifupdown-ng syntax appears as follows:

Contents of /etc/network/interfaces

... auto eth0 iface eth0 use dhcp

All further configuration below assumes ifupdown-ng being used, unless stated otherwise.

IPv6 stateless autoconfiguration

With IPv6, stateless auto-configuration is typically used to configure network interfaces. If you are not interested in using IPv4 at all, you can simply use the ipv6-ra executor to ensure that an interface is configured to accept IPv6 RA advertisements:

Contents of /etc/network/interfaces

... auto eth0 iface eth0 use ipv6-ra

Static address configuration

Note: If ifupdown-ng is not available/used, use iface eth0 inet static instead of iface eth0 and use below address format for IPv4 instead of 203.0.113.2/24  :

Contents of /etc/network/interfaces

address 203.0.113.2 netmask 255.255.255.0

Add the following to the file /etc/network/interfaces:

Contents of /etc/network/interfaces

... auto eth0 iface eth0 address 203.0.113.2/24 gateway 203.0.113.1
Multiple address

Contents of /etc/network/interfaces

... auto eth0 iface eth0 address 203.0.113.2/24 address 203.0.113.3/24 address 203.0.113.4/24 gateway 203.0.113.1
Dual-stack configuration

This example shows a dual-stack configuration.

Contents of /etc/network/interfaces

... auto eth0 iface eth0 address 203.0.113.2/24 address 203.0.113.3/24 address 203.0.113.4/24 gateway 203.0.113.1 address 2001:db8:1000:2::2/64 address 2001:db8:1000:2::3/64 address 2001:db8:1000:2::4/64 gateway 2001:db8:1000:2::1

Networking service

Changes made to /etc/network/interfaces can be activated by running:

# rc-service networking restart

To start (or restart) the networking service:

# rc-service networking --quiet start &

To add networking service so that it starts on boot:

# rc-update add networking boot

Firewall

Alpine Linux provides multiple firewall software. Some of the prominent ones are listed below:

Troubleshooting

Connectivity testing

Test if networking is configured properly by attempting to ping out:

$ ping www.google.com PING www.l.google.com (74.125.47.103) 56(84) bytes of data. 64 bytes from yw-in-f103.1e100.net (74.125.47.103): icmp_seq=1 ttl=48 time=58.5 ms 64 bytes from yw-in-f103.1e100.net (74.125.47.103): icmp_seq=2 ttl=48 time=56.4 ms 64 bytes from yw-in-f103.1e100.net (74.125.47.103): icmp_seq=3 ttl=48 time=57.0 ms 64 bytes from yw-in-f103.1e100.net (74.125.47.103): icmp_seq=4 ttl=48 time=60.2 ms ^C --- www.l.google.com ping statistics --- 4 packets transmitted, 4 received, 0% packet loss, time 3007ms rtt min/avg/max/mdev = 56.411/58.069/60.256/1.501 ms

For an IPv6 traceroute run traceroute6:

$ traceroute6 ipv6.google.com traceroute to ipv6.l.google.com (2001:4860:8009::67) from 2001:470:ffff:ff::2, 30 hops max, 16 byte packets 1 2001:470:ffff:ff::1 (2001:470:ffff:ff::1) 3.49 ms 0.62 ms 0.607 ms 2 * * * 3 * * * 4 pr61.iad07.net.google.com (2001:504:0:2:0:1:5169:1) 134.313 ms 95.342 ms 88.425 ms 5 2001:4860::1:0:9ff (2001:4860::1:0:9ff) 100.759 ms 100.537 ms 89.907 ms 6 2001:4860::1:0:5db (2001:4860::1:0:5db) 115.563 ms 102.946 ms 106.191 ms 7 2001:4860::2:0:a7 (2001:4860::2:0:a7) 101.754 ms 100.475 ms 100.512 ms 8 2001:4860:0:1::c3 (2001:4860:0:1::c3) 99.272 ms 111.989 ms 99.835 ms 9 yw-in-x67.1e100.net (2001:4860:8009::67) 101.545 ms 109.675 ms 99.431 ms

iproute2

Install the iproute2 package which provides the 'ss' command which is an alternate to netstat.:

# apk add iproute2

Show listening tcp ports:

$ ss -tl

Show listening tcp ports and associated processes:

$ ss -ptl

Show listening and established tcp connections:

$ ss -ta

Show socket usage summary:

$ ss -s

Show more options:

$ ss -h

drill

Install drill (it will also install the 'ldns' package) which is a superior replacement for nslookup and dig etc:

# apk add drill

Then use it as you would for dig:

$ drill alpinelinux.org @8.8.8.8

To perform a reverse lookup (get a name from an IP) use the following syntax:

$ drill -x 8.8.8.8 @208.67.222.222

Missing interface

To list your available network interfaces use the commands ip link or ip a. Refer to Wifi troubleshooting page for issues related to wireless interfaces. If nothing works, you may have to use an alternate interface (e.g. a usb to ethernet adapter).

See also

You may also wish to review the following network related articles:

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