Alpine Linux - User contributions [en]

Configure Networking

2010-10-25T17:13:51Z

Hinman:

This page will assist you in setting up networking on Alpine Linux.
{{Note|You must be logged in as root in order to perform the actions on this page.}}

= Setting System Hostname =
To set the system hostname, do something like the following:
{{Cmd|echo "hostname.domain.com" > /etc/hostname}}

Then, to activate the change, do the following:
{{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:
<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 are 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 are 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 <code>/etc/hosts</code> file.

Here's an IPv4 example:
<pre>192.168.1.150 hostname.domain.com</pre>

And here's an IPv6 example:
<pre>2001:470:ffff:ff::2 hostname.domain.com</pre>

= Configuring DNS =
{{Warning|'''For users of IPv4 DHCP:''' Please note that <code>/etc/resolv.conf</code> will be completely overwritten with any nameservers provided by DHCP. Also, if DHCP does not provide any nameservers, then <code>/etc/resolv.conf</code> will still be overwritten, but will not contain any nameservers! '''''Note to self: This behavior should probably be reported to upstream.'''''}}
{{Note|'''For users of IPv6 Stateless Autoconfiguration:''' The above warning doesn't seem to be an issue here, however, I would advise caution.}}

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

For IPv4 nameservers, edit your <code>/etc/resolv.conf</code> file to look like this: 
This example uses [http://en.wikipedia.org/wiki/Google_Public_DNS Google's Public DNS servers].
{{Cmd|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: 
This example uses [http://www.he.net/ Hurricane Electric's] public DNS server.
{{Cmd|nameserver 2001:470:20::2}}

{{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 IPv4 DNS Servers in the first example.) Read [http://www.google.com/intl/en/ipv6/ here] for more information.}}

= Enabling IPv6 (Optional) =

If you use IPv6, do the following to enable IPv6 for now and at each boot:
<pre>modprobe ipv6
echo "ipv6" >> /etc/modules</pre>

= Interface Configuration =

== Loopback Configuration (Required) ==
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 setup the IPv4 loopback address (127.0.0.1), and the IPv6 loopback address (<code>::1</code>) — if you enabled IPv6.

== Ethernet Configuration ==
For the following Ethernet configuration examples, we will assume that you are using Ethernet device <code>eth0</code>.

=== Initial Configuration ===
Add the following to the file <code>/etc/network/interfaces</code>, above any IP configuration for <code>eth0</code>:
<pre>auto eth0</pre>

=== IPv4 DHCP Configuration ===
Add the following to the file <code>/etc/network/interfaces</code>, below the <code>auto eth0</code> definition:
<pre>iface eth0 inet dhcp</pre>

=== IPv4 Static Address Configuration ===
Add the following to the file <code>/etc/network/interfaces</code>, below the <code>auto eth0</code> definition:
<pre>iface eth0 inet static
address 192.168.1.150
netmask 255.255.255.0
gateway 192.168.1.1</pre>

=== IPv6 Stateless Autoconfiguration ===
Add the following to the file <code>/etc/network/interfaces</code>, below the <code>auto eth0</code> definition:
<pre>iface eth0 inet6 manual
pre-up echo 1 > /proc/sys/net/ipv6/conf/eth0/accept_ra</pre>

{{Note|'''''The inet6 "manual" method is not yet available in busybox. A patch has been submitted for review.'''''}}

=== IPv6 Static Address Configuration ===
Add the following to the file <code>/etc/network/interfaces</code>, below the <code>auto eth0</code> definition:
<pre>iface eth0 inet6 static
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>

== Example: Dual-Stack Configuration ==
This example shows a dual-stack configuration.
<pre>auto lo
iface lo inet loopback

auto eth0

iface eth0 inet static
address 192.168.1.150
netmask 255.255.255.0
gateway 192.168.1.1

iface eth0 inet6 static
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>

= Firewalling with iptables and ip6tables =
== Install iptables ==
{{ Cmd|apk add iptables }}

== Configure iptables/ip6tables ==
{{ Tip| Good examples of how to write iptables rules can be found at the Linux Home Networking Wiki http://www.linuxhomenetworking.com/wiki/index.php/Quick_HOWTO_:_Ch14_:_Linux_Firewalls_Using_iptables }}

== Save Firewall Rules ==
# Set iptables to start on reboot
#* {{ Cmd| rc-update add iptables }}
#Write the firewall rules to disk
#* {{ Cmd| /etc/init.d/iptables save}}
# Add the firewall rules to Alpine local backup
#*{{ Cmd| lbu add /var/lib/iptables/rules-save }}
# Save the configuration
#*{{ Cmd| lbu ci }}

= Activating Changes and Testing Connectivity =
Changes made to <code>/etc/network/interfaces</code> can be activated by running:
{{Cmd|/etc/init.d/networking restart}}
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=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</pre>

For an IPv6 traceroute (<code>traceroute6</code>), you will first need to install the <code>iputils</code> package:
{{Cmd|apk add iputils}}

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
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</pre>

Configure Networking

2010-10-25T17:09:31Z

Hinman: /* Configure iptables/ip6tables */

This page will assist you in setting up networking on Alpine Linux.
{{Note|You must be logged in as root in order to perform the actions on this page.}}

= Setting System Hostname =
To set the system hostname, do something like the following:
{{Cmd|echo "hostname.domain.com" > /etc/hostname}}

Then, to activate the change, do the following:
{{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:
<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 are 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 are 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 <code>/etc/hosts</code> file.

Here's an IPv4 example:
<pre>192.168.1.150 hostname.domain.com</pre>

And here's an IPv6 example:
<pre>2001:470:ffff:ff::2 hostname.domain.com</pre>

= Configuring DNS =
{{Warning|'''For users of IPv4 DHCP:''' Please note that <code>/etc/resolv.conf</code> will be completely overwritten with any nameservers provided by DHCP. Also, if DHCP does not provide any nameservers, then <code>/etc/resolv.conf</code> will still be overwritten, but will not contain any nameservers! '''''Note to self: This behavior should probably be reported to upstream.'''''}}
{{Note|'''For users of IPv6 Stateless Autoconfiguration:''' The above warning doesn't seem to be an issue here, however, I would advise caution.}}

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

For IPv4 nameservers, edit your <code>/etc/resolv.conf</code> file to look like this: 
This example uses [http://en.wikipedia.org/wiki/Google_Public_DNS Google's Public DNS servers].
{{Cmd|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: 
This example uses [http://www.he.net/ Hurricane Electric's] public DNS server.
{{Cmd|nameserver 2001:470:20::2}}

{{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 IPv4 DNS Servers in the first example.) Read [http://www.google.com/intl/en/ipv6/ here] for more information.}}

= Enabling IPv6 (Optional) =

If you use IPv6, do the following to enable IPv6 for now and at each boot:
<pre>modprobe ipv6
echo "ipv6" >> /etc/modules</pre>

= Interface Configuration =

== Loopback Configuration (Required) ==
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 setup the IPv4 loopback address (127.0.0.1), and the IPv6 loopback address (<code>::1</code>) — if you enabled IPv6.

== Ethernet Configuration ==
For the following Ethernet configuration examples, we will assume that you are using Ethernet device <code>eth0</code>.

=== Initial Configuration ===
Add the following to the file <code>/etc/network/interfaces</code>, above any IP configuration for <code>eth0</code>:
<pre>auto eth0</pre>

=== IPv4 DHCP Configuration ===
Add the following to the file <code>/etc/network/interfaces</code>, below the <code>auto eth0</code> definition:
<pre>iface eth0 inet dhcp</pre>

=== IPv4 Static Address Configuration ===
Add the following to the file <code>/etc/network/interfaces</code>, below the <code>auto eth0</code> definition:
<pre>iface eth0 inet static
address 192.168.1.150
netmask 255.255.255.0
gateway 192.168.1.1</pre>

=== IPv6 Stateless Autoconfiguration ===
Add the following to the file <code>/etc/network/interfaces</code>, below the <code>auto eth0</code> definition:
<pre>iface eth0 inet6 manual
pre-up echo 1 > /proc/sys/net/ipv6/conf/eth0/accept_ra</pre>

{{Note|'''''The inet6 "manual" method is not yet available in busybox. A patch has been submitted for review.'''''}}

=== IPv6 Static Address Configuration ===
Add the following to the file <code>/etc/network/interfaces</code>, below the <code>auto eth0</code> definition:
<pre>iface eth0 inet6 static
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>

== Example: Dual-Stack Configuration ==
This example shows a dual-stack configuration.
<pre>auto lo
iface lo inet loopback

auto eth0

iface eth0 inet static
address 192.168.1.150
netmask 255.255.255.0
gateway 192.168.1.1

iface eth0 inet6 static
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>

= Firewalling with iptables and ip6tables =
== Install iptables ==
{{ Cmd|apk add iptables }}

== Configure iptables/ip6tables ==
{{ Tip| Good examples of how to write iptables rules can be found at the Linux Home Networking Wiki http://www.linuxhomenetworking.com/wiki/index.php/Quick_HOWTO_:_Ch14_:_Linux_Firewalls_Using_iptables }}

== Save Firewall Rules ==
# Set iptables to start on reboot
#* {{ Cmd| rc-update add iptables }}
#Write the firewall rules to disk
#* {{ Cmd| /etc/init.d/iptables save}}
# Add the firewall rules to lbu
#*{{ Cmd| lbu add /var/lib/iptables/rules-save }}
# Save the configuration
#*{{ Cmd| lbu ci }}

= Activating Changes and Testing Connectivity =
Changes made to <code>/etc/network/interfaces</code> can be activated by running:
{{Cmd|/etc/init.d/networking restart}}
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=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</pre>

For an IPv6 traceroute (<code>traceroute6</code>), you will first need to install the <code>iputils</code> package:
{{Cmd|apk add iputils}}

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
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</pre>

Configure Networking

2010-10-25T16:08:02Z

Hinman: /* Save Firewall Rules */

This page will assist you in setting up networking on Alpine Linux.
{{Note|You must be logged in as root in order to perform the actions on this page.}}

= Setting System Hostname =
To set the system hostname, do something like the following:
{{Cmd|echo "hostname.domain.com" > /etc/hostname}}

Then, to activate the change, do the following:
{{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:
<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 are 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 are 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 <code>/etc/hosts</code> file.

Here's an IPv4 example:
<pre>192.168.1.150 hostname.domain.com</pre>

And here's an IPv6 example:
<pre>2001:470:ffff:ff::2 hostname.domain.com</pre>

= Configuring DNS =
{{Warning|'''For users of IPv4 DHCP:''' Please note that <code>/etc/resolv.conf</code> will be completely overwritten with any nameservers provided by DHCP. Also, if DHCP does not provide any nameservers, then <code>/etc/resolv.conf</code> will still be overwritten, but will not contain any nameservers! '''''Note to self: This behavior should probably be reported to upstream.'''''}}
{{Note|'''For users of IPv6 Stateless Autoconfiguration:''' The above warning doesn't seem to be an issue here, however, I would advise caution.}}

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

For IPv4 nameservers, edit your <code>/etc/resolv.conf</code> file to look like this: 
This example uses [http://en.wikipedia.org/wiki/Google_Public_DNS Google's Public DNS servers].
{{Cmd|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: 
This example uses [http://www.he.net/ Hurricane Electric's] public DNS server.
{{Cmd|nameserver 2001:470:20::2}}

{{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 IPv4 DNS Servers in the first example.) Read [http://www.google.com/intl/en/ipv6/ here] for more information.}}

= Enabling IPv6 (Optional) =

If you use IPv6, do the following to enable IPv6 for now and at each boot:
<pre>modprobe ipv6
echo "ipv6" >> /etc/modules</pre>

= Interface Configuration =

== Loopback Configuration (Required) ==
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 setup the IPv4 loopback address (127.0.0.1), and the IPv6 loopback address (<code>::1</code>) — if you enabled IPv6.

== Ethernet Configuration ==
For the following Ethernet configuration examples, we will assume that you are using Ethernet device <code>eth0</code>.

=== Initial Configuration ===
Add the following to the file <code>/etc/network/interfaces</code>, above any IP configuration for <code>eth0</code>:
<pre>auto eth0</pre>

=== IPv4 DHCP Configuration ===
Add the following to the file <code>/etc/network/interfaces</code>, below the <code>auto eth0</code> definition:
<pre>iface eth0 inet dhcp</pre>

=== IPv4 Static Address Configuration ===
Add the following to the file <code>/etc/network/interfaces</code>, below the <code>auto eth0</code> definition:
<pre>iface eth0 inet static
address 192.168.1.150
netmask 255.255.255.0
gateway 192.168.1.1</pre>

=== IPv6 Stateless Autoconfiguration ===
Add the following to the file <code>/etc/network/interfaces</code>, below the <code>auto eth0</code> definition:
<pre>iface eth0 inet6 manual
pre-up echo 1 > /proc/sys/net/ipv6/conf/eth0/accept_ra</pre>

{{Note|'''''The inet6 "manual" method is not yet available in busybox. A patch has been submitted for review.'''''}}

=== IPv6 Static Address Configuration ===
Add the following to the file <code>/etc/network/interfaces</code>, below the <code>auto eth0</code> definition:
<pre>iface eth0 inet6 static
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>

== Example: Dual-Stack Configuration ==
This example shows a dual-stack configuration.
<pre>auto lo
iface lo inet loopback

auto eth0

iface eth0 inet static
address 192.168.1.150
netmask 255.255.255.0
gateway 192.168.1.1

iface eth0 inet6 static
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>

= Firewalling with iptables and ip6tables =
== Install iptables ==
{{ Cmd|apk add iptables }}

== Configure iptables/ip6tables ==
== Save Firewall Rules ==
# Set iptables to start on reboot
#* {{ Cmd| rc-update add iptables }}
#Write the firewall rules to disk
#* {{ Cmd| /etc/init.d/iptables save}}
# Add the firewall rules to lbu
#*{{ Cmd| lbu add /var/lib/iptables/rules-save }}
# Save the configuration
#*{{ Cmd| lbu ci }}

= Activating Changes and Testing Connectivity =
Changes made to <code>/etc/network/interfaces</code> can be activated by running:
{{Cmd|/etc/init.d/networking restart}}
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=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</pre>

For an IPv6 traceroute (<code>traceroute6</code>), you will first need to install the <code>iputils</code> package:
{{Cmd|apk add iputils}}

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
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</pre>

Configure Networking

2010-10-25T15:13:08Z

Hinman: /* Install iptables */

This page will assist you in setting up networking on Alpine Linux.
{{Note|You must be logged in as root in order to perform the actions on this page.}}

= Setting System Hostname =
To set the system hostname, do something like the following:
{{Cmd|echo "hostname.domain.com" > /etc/hostname}}

Then, to activate the change, do the following:
{{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:
<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 are 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 are 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 <code>/etc/hosts</code> file.

Here's an IPv4 example:
<pre>192.168.1.150 hostname.domain.com</pre>

And here's an IPv6 example:
<pre>2001:470:ffff:ff::2 hostname.domain.com</pre>

= Configuring DNS =
{{Warning|'''For users of IPv4 DHCP:''' Please note that <code>/etc/resolv.conf</code> will be completely overwritten with any nameservers provided by DHCP. Also, if DHCP does not provide any nameservers, then <code>/etc/resolv.conf</code> will still be overwritten, but will not contain any nameservers! '''''Note to self: This behavior should probably be reported to upstream.'''''}}
{{Note|'''For users of IPv6 Stateless Autoconfiguration:''' The above warning doesn't seem to be an issue here, however, I would advise caution.}}

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

For IPv4 nameservers, edit your <code>/etc/resolv.conf</code> file to look like this: 
This example uses [http://en.wikipedia.org/wiki/Google_Public_DNS Google's Public DNS servers].
{{Cmd|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: 
This example uses [http://www.he.net/ Hurricane Electric's] public DNS server.
{{Cmd|nameserver 2001:470:20::2}}

{{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 IPv4 DNS Servers in the first example.) Read [http://www.google.com/intl/en/ipv6/ here] for more information.}}

= Enabling IPv6 (Optional) =

If you use IPv6, do the following to enable IPv6 for now and at each boot:
<pre>modprobe ipv6
echo "ipv6" >> /etc/modules</pre>

= Interface Configuration =

== Loopback Configuration (Required) ==
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 setup the IPv4 loopback address (127.0.0.1), and the IPv6 loopback address (<code>::1</code>) — if you enabled IPv6.

== Ethernet Configuration ==
For the following Ethernet configuration examples, we will assume that you are using Ethernet device <code>eth0</code>.

=== Initial Configuration ===
Add the following to the file <code>/etc/network/interfaces</code>, above any IP configuration for <code>eth0</code>:
<pre>auto eth0</pre>

=== IPv4 DHCP Configuration ===
Add the following to the file <code>/etc/network/interfaces</code>, below the <code>auto eth0</code> definition:
<pre>iface eth0 inet dhcp</pre>

=== IPv4 Static Address Configuration ===
Add the following to the file <code>/etc/network/interfaces</code>, below the <code>auto eth0</code> definition:
<pre>iface eth0 inet static
address 192.168.1.150
netmask 255.255.255.0
gateway 192.168.1.1</pre>

=== IPv6 Stateless Autoconfiguration ===
Add the following to the file <code>/etc/network/interfaces</code>, below the <code>auto eth0</code> definition:
<pre>iface eth0 inet6 manual
pre-up echo 1 > /proc/sys/net/ipv6/conf/eth0/accept_ra</pre>

{{Note|'''''The inet6 "manual" method is not yet available in busybox. A patch has been submitted for review.'''''}}

=== IPv6 Static Address Configuration ===
Add the following to the file <code>/etc/network/interfaces</code>, below the <code>auto eth0</code> definition:
<pre>iface eth0 inet6 static
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>

== Example: Dual-Stack Configuration ==
This example shows a dual-stack configuration.
<pre>auto lo
iface lo inet loopback

auto eth0

iface eth0 inet static
address 192.168.1.150
netmask 255.255.255.0
gateway 192.168.1.1

iface eth0 inet6 static
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>

= Firewalling with iptables and ip6tables =
== Install iptables ==
{{ Cmd|apk add iptables }}

== Configure iptables/ip6tables ==
== Save Firewall Rules ==

= Activating Changes and Testing Connectivity =
Changes made to <code>/etc/network/interfaces</code> can be activated by running:
{{Cmd|/etc/init.d/networking restart}}
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=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</pre>

For an IPv6 traceroute (<code>traceroute6</code>), you will first need to install the <code>iputils</code> package:
{{Cmd|apk add iputils}}

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
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</pre>