Configure Networking: Difference between revisions

From Alpine Linux
("quick post" to get the network configuration page started)
 
(Overhauled layout and wording (Not yet stable, however, but closer))
Line 8: Line 8:
{{Cmd|echo "hostname.domain.com" > /etc/hostname}}
{{Cmd|echo "hostname.domain.com" > /etc/hostname}}


To activate the change, do the following:
Then, to activate the change, do the following:
{{Cmd|hostname -F /etc/hostname}}
{{Cmd|hostname -F /etc/hostname}}


{{Tip|From here, you can skip to the [[#DHCP_.28Automatic_Configuration.29|IPv4 DHCP]] section if you want an Automatic IP (DHCP). Otherwise, if you are going for a Static IP configuration, please continue below.}}
If you're using IPv6, you should also add the following special IPv6 addresses to your <code>/etc/hosts</code> file:
{{Note|Does DHCP provide the DNS servers, or do they need to be added manually?  This needs to be tested and documented here.}}
<pre>::1            localhost ipv6-localhost ipv6-loopback
It's also a good idea to add the hostname to the <code>/etc/hosts</code> file, e.g.:
fe00::0        ipv6-localnet
<pre>127.0.0.1      localhost.localdomain  localhost
ff00::0        ipv6-mcastprefix
192.168.1.150  hostname.domain.com   hostname</pre>
ff02::1        ipv6-allnodes
Where:
ff02::2        ipv6-allrouters
* <code>192.168.1.150</code> is the static IP address (IPv4) of the Alpine Linux machine.
ff02::3        ipv6-allhosts</pre>
* <code>hostname.domain.com</code> is the FQDN (hostname) we set above.
 
* <code>hostname</code> is the just the host portion from the FQDN we set above.
{{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 =
= Configuring DNS =
For simple DNS resolution, do something like the following:
{{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.'''''}}
{{Cmd|echo "nameserver 8.8.8.8" > /etc/resolv.conf
{{Warning|'''For users of IPv6 Stateless Autoconfiguration:''' ''This needs to be looked into to determine if IPv6 Stateless Autoconfiguration suffers from the same issue.''}}
echo "nameserver 8.8.4.4" >> /etc/resolv.conf}}
 
The above example uses [http://en.wikipedia.org/wiki/Google_Public_DNS Google's Public DNS servers].
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:<br />
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:<br />
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 to be able to access 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>


= Loopback Configuration =
= Interface Configuration =
 
== Loopback Configuration (Required) ==
{{Tip|It's a good idea (read: required) that you configure loopback.}}
{{Tip|It's a good idea (read: required) that you configure loopback.}}
To configure loopback, add the following to a new file <code>/etc/network/interfaces</code>:
To configure loopback, add the following to a new file <code>/etc/network/interfaces</code>:
Line 33: Line 60:
iface lo inet loopback</pre>
iface lo inet loopback</pre>


= IPv4 Configuration =
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.
== DHCP (Automatic Configuration) ==
{{Note|DHCP configuration details pending.}}


== Static IPv4 ==
== Ethernet Configuration ==
As an example, to configure <code>eth0</code> for a static IPv4 address, add the following to <code>/etc/network/interfaces</code>:
For the following Ethernet configuration examples, we will assume that you are using Ethernet device <code>eth0</code>.
<pre>auto eth0
 
iface eth0 inet static
=== 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
         address 192.168.1.150
         netmask 255.255.255.0
         netmask 255.255.255.0
         gateway 192.168.1.1</pre>
         gateway 192.168.1.1</pre>


= IPv6 Configuration =
=== IPv6 Stateless Autoconfiguration ===
== Loading the <code>ipv6</code> Kernel Module ==
{{Note|''Stateless address autoconfiguration details pending.''}}
In order to use IPv6 on Alpine Linux, you must first load the <code>ipv6</code> kernel module.


To load it manually for the first time, run:
=== IPv6 Static Address Configuration ===
{{Cmd|modprobe ipv6}}
Add the following to the file <code>/etc/network/interfaces</code>, below the <code>auto eth0</code> definition:
Now, to set it to load on boot from now on, run:
{{Cmd|echo "ipv6" >> /etc/modules}}
 
Now you are ready to configure Alpine Linux for IPv6.
 
== Stateless Address Autoconfiguration ==
{{Note|Stateless address autoconfiguration details pending.}}
 
== Static IPv6 ==
As an example, to configure <code>eth0</code> for a static IPv6 address, add the following to <code>/etc/network/interfaces</code>:
{{Tip|Be sure that you have ''one'' '''auto eth0''' definition in your /etc/network/interfaces file, if not already. See the Static IPv4 configuration above.}}
<pre>iface eth0 inet6 static
<pre>iface eth0 inet6 static
         address 2001:470:ffff:ff::2
         address 2001:470:ffff:ff::2
         netmask 64
         netmask 64
         gateway 2001:470:ffff:ff::1</pre>
         gateway 2001:470:ffff:ff::1</pre>
= iptables and ip6tables =
== Install iptables ==
== Configure iptables or ip6tables ==
== Save Rules for Reboot ==


= Activating Changes and Testing Connectivity =
= Activating Changes and Testing Connectivity =

Revision as of 05:04, 2 September 2010

This material is work-in-progress ...

Do not follow instructions here until this notice is removed.
(Last edited by Mattx86 on 2 Sep 2010.)

This page will assist you in setting up basic 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:

echo "hostname.domain.com" > /etc/hostname

Then, to activate the change, do the following:

hostname -F /etc/hostname

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

::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 are going to use automatic IP configuration, such as IPv4 DHCP or IPv6 Stateless Autoconfiguration, you can skip ahead to 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 /etc/hosts file.

Here's an IPv4 example: 

192.168.1.150   hostname.domain.com

And here's an IPv6 example: 

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

Configuring DNS

Warning: For users of IPv4 DHCP: Please note that /etc/resolv.conf will be completely overwritten with any nameservers provided by DHCP. Also, if DHCP does not provide any nameservers, then /etc/resolv.conf will still be overwritten, but will not contain any nameservers! Note to self: This behavior should probably be reported to upstream.


Warning: For users of IPv6 Stateless Autoconfiguration: This needs to be looked into to determine if IPv6 Stateless Autoconfiguration suffers from the same issue.


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

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

nameserver 8.8.8.8 nameserver 8.8.4.4

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

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 to be able to access 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 IPv4 DNS Servers in the first example.) Read here for more information.

Enabling IPv6 (Optional)

If you use IPv6, do the following to enable IPv6 for now and at each boot: 

modprobe ipv6
echo "ipv6" >> /etc/modules

Interface Configuration

Loopback Configuration (Required)

Tip: It's a good idea (read: required) that you configure loopback.

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

auto lo
iface lo inet loopback

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

Ethernet Configuration

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

Initial Configuration

Add the following to the file /etc/network/interfaces, above any IP configuration for eth0: 

auto eth0

IPv4 DHCP Configuration

Add the following to the file /etc/network/interfaces, below the auto eth0 definition: 

iface eth0 inet dhcp

IPv4 Static Address Configuration

Add the following to the file /etc/network/interfaces, below the auto eth0 definition: 

iface eth0 inet static
        address 192.168.1.150
        netmask 255.255.255.0
        gateway 192.168.1.1

IPv6 Stateless Autoconfiguration

Note: Stateless address autoconfiguration details pending.

IPv6 Static Address Configuration

Add the following to the file /etc/network/interfaces, below the auto eth0 definition: 

iface eth0 inet6 static
        address 2001:470:ffff:ff::2
        netmask 64
        gateway 2001:470:ffff:ff::1

iptables and ip6tables

Install iptables

Configure iptables or ip6tables

Save Rules for Reboot

Activating Changes and Testing Connectivity

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

/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:

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 (traceroute6), you will first need to install the iputils package:

apk add iputils

Then 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
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