Difference between revisions of "Sharing PPP Connection"

From ArchWiki
Jump to: navigation, search
m (moved Sharing ppp connection with eth interface to Sharing PPP Connection: more concise; merging another article onto this one)
(cleaned up the article a litte. modified, but not tested: ifconfig -> ip is pretty safe. there's still iwconfig -> iw, but i don't use PPP so not gonna break that just yet)
(6 intermediate revisions by 5 users not shown)
Line 1: Line 1:
[[Category:Networking (English)]]
+
[[Category:Networking]]
[[Category:HOWTOs (English)]]
 
 
 
= Sharing via wired ethernet =
 
  
 
== Requirements ==
 
== Requirements ==
The following programs must have been installed in order to share the ppp connection:
+
Before proceeding, you must make sure:
# Programs for configuring generic network interface card (package '''net-tools''')
+
# You must have a working PPP connection.
# The '''iptables''' program which is used to manipulate how data is passed through your machine from your clients and back (package '''iptables''')
+
# You must have an extra Ethernet interface card in your computer with which to share your connection.
# '''dnsmasq''' software for acting as a DHCP and DNS caching server (package '''dnsmasq''')
 
# If you want to share the ppp connection with more computers you need to setup a network bridge. (package '''bridge-utils''')
 
  
 +
== Installing ==
 +
The following packages must be [[Pacman|installed]] from the [[official repositories]] for both Wired and Wireless sharing:
 +
* {{Pkg|iptables}}: for controlling packets in your network.
 +
* {{Pkg|dnsmasq}}: for acting as a DHCP and DNS caching server.
 +
* {{Pkg|bridge-utils}}: for setting up a network bridge.
  
The following conditions must also have been met:
+
Depending on whether you want to share a wireless or wired connection, you also have to install:
# You must have a working ppp connection
+
* '''wired''': {{Pkg|iproute2}} or {{Pkg|net-tools}} (this article uses {{ic|iproute2}} since {{ic|net-tools}} is no longer maintained).
# You must have a working an extra eth interface card (in terms of "can be used in Linux")
+
* '''wireless''': {{Pkg|wireless_tools}}.
  
== Instructions ==
+
== Sharing via Wired Ethernet ==
  
<ol>
+
* Set the PPP connection up.
<li>Set the ppp connection up.</li>
+
: You can assign an IP address to the interface as usual, by running (as root):
you can assign an ip address to the interface as usual, by running (again, as root): <pre>ifconfig eth1 192.168.0.254</pre>
+
# ip addr add 192.168.0.254 dev eth0
<li>Set the kernel to router mode. This is done by running as root: <pre>echo 1 > /proc/sys/net/ipv4/ip_forward</pre></li>
+
* Set the kernel to router mode. This is done by running:
<li>Configure '''dnsmasqd'''. Make the following changes to /etc/dnsmasq.conf (uncomment if necessary): <pre>
+
# echo 1 > /proc/sys/net/ipv4/ip_forward
 +
* Configure {{ic|dnsmasqd}}. Make the following changes to {{ic|/etc/dnsmasq.conf}} (uncomment if necessary):
 +
{{hc|/etc/dnsmasq.conf|<nowiki>
 
domain-needed
 
domain-needed
 
bogus-priv
 
bogus-priv
interface=eth1 (or whatever interface your wlan is)
+
interface=eth0 # change to your chosen interface
dhcp-range=192.168.0.1,192.168.0.100,12h
+
dhcp-range=192.168.0.1,192.168.0.100,12h</nowiki>
</pre></li>
+
}}
<li>Start the dnsmasqd, as root: <pre>/etc/rc.d/dnsmasq start</pre></li>
+
* [[Daemons#Managing_daemons|Start]] the '''dnsmasq''' daemon.
<li>Finally, set firewall to forward connections to and from the Internet for clients connecting to your wlan. This is done by issuing (you guessed it right, as root again): <pre>iptables -t nat -A POSTROUTING -o ppp0 -j MASQUERADE</pre> In the above the '''''ppp0''''' interface is the used ppp interface, you can substitute it for yours if needed.</li>
+
* Finally, set firewall to forward connections to and from the Internet for clients connecting to your WLAN. This is done by issuing:
<li>You are done! Happy surfing</li>
+
# iptables -t nat -A POSTROUTING -o ppp0 -j MASQUERADE
</ol>
+
:In the above the '''ppp0''' interface is the used PPP interface, you can substitute it for yours if needed.
 +
* You are done! Happy surfing!
 +
 
 +
{{Warning|The previous configuration has no security options enabled. If you are using a firewall, you should adapt this documentation to suit your needs. Same applies also to setting up keys for WLAN interface.}}
 +
 
 +
=== Network Bridge ===
 +
Let's assume your PPP connection is on {{ic|eth0}}, and you want to share the connection on {{ic|eth1}} and {{ic|eth2}}.
 +
 
 +
# ip addr add 0.0.0.0 dev eth1  # remove IP from eth0
 +
# ip link set eth1 up          # ensure the interface is up
 +
 
 +
# ip addr add 0.0.0.0 dev eth2  # remove IP from eth1
 +
# ip link set eth2 up          # ensure the interface is up
 +
 
 +
# brctl addbr br0              # create br0 node
 +
# brctl addif br0 eth1          # add eth0 to bridge br0
 +
# brctl addif br0 eth2          # add eth1 to bridge br0
  
{{Warning|The previous configuration has no security options enabled!<br>If you are using firewall, you should adapt this documentation to suit your needs.<br>Same applies also to setting up keys for wlan interface.}}
+
# ip addr add 192.168.0.254 dev br0
 +
change your interface in {{ic|dnsmasq.conf}} to {{ic|br0}}:
 +
interface=br0
 +
and [[Daemons#Managing_daemons|restart]] the '''dnsmasq''' daemon.
  
== Network Bridge ==
+
Now you should be able to connect to the internet using {{ic|eth1}} or {{ic|eth2}}.
  
Let's assume your ppp connection is on eth0, and you want to share the connection on eth1 and eth2.
+
== Sharing via WLAN ==
  
ifconfig eth1 0.0.0.0 #remove IP from eth0
+
=== Instructions ===
ifconfig eth1 up #ensure the interface is up
 
  
ifconfig eth2 0.0.0.0 #remove IP from eth1
+
* Set up the PPP connection.
ifconfig eth2 up #ensure the interface is up
+
* Set up the WLAN connection: choose an SSID and select Ad-hoc as network type. In the following it is assumed that you are using the {{ic|wlan0}} interface.
  
brctl addbr br0 #create br0 node
+
: Set the {{ic|wlan0}} interface up address for example 192.168.0.254. Setting up the interface is usually done by running:
brctl addif br0 eth1 #add eth0 to bridge br0
+
  # iwconfig wlan0 essid "MyFreeWlan" mode ad-hoc
  brctl addif br0 eth2 #add eth1 to bridge br0
 
  
  ifconfig br0 192.168.0.254
+
: After that you can assign an IP address to the interface as usual, by running:
change your interface in dnsmasq.conf to br0
+
  # ip addr add 192.168.0.254 dev wlan0
  interface=br0
+
: Please note that different wlan cards may be configured differently and one should adapt this documentation accordingly.
 +
* Set the kernel to router mode. This is done by running:
 +
# echo 1 > /proc/sys/net/ipv4/ip_forward
 +
* Configure '''dnsmasq'''. Make the following changes to {{ic|/etc/dnsmasq.conf}} (uncomment if necessary):
 +
{{hc|etc/dnsmasq.conf|<nowiki>
 +
domain-needed
 +
bogus-priv
 +
interface=wlan0    # change to your interface
 +
dhcp-range=192.168.0.1,192.168.0.100,12h</nowiki>
 +
}}
 +
* [[Daemons#Managing_daemons|Start]] the '''dnsmasq''' daemon.
 +
* Finally, set firewall to forward connections to and from the Internet for clients connecting to your WLAN. This is done by issuing:
 +
  # iptables -t nat -A POSTROUTING -o ppp0 -j MASQUERADE
  
then start dnsmasq
+
: In the above the '''ppp0''' interface is assumed to be the used PPP interface, you can substitute it for yours if needed.
/etc/rc.d/dnsmasq start
+
* You are done! Happy surfing!
  
now you can connect to the internet using eth1 or eth2.
+
{{Warning|The previous configuration has no security options enabled! If you are using firewall, you should adapt this documentation to suit your needs. Same applies also to setting up keys for wlan interface.}}
  
== See Also ==
+
== Sharing Script ==
 +
A quick script for sharing {{ic|eth0}} over {{ic|wlan0}} on an ad-hoc network.
 +
{{hc|ethoverwlan.sh|
 +
#!/bin/bash
  
*[[Internet Share]]
+
iwconfig wlan0 mode ad-hoc
*[[Simple stateful firewall HOWTO]]
+
iwconfig wlan0 essid proxywlan
*[[NAT'ing firewall - Share your broadband connection]]
+
ip addr add 192.168.0.254 dev wlan0
*[[Wireless Setup]]
+
ip link set wlan0 up
*[[USB 3G Modem]]
+
iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE
 +
echo 1 > /proc/sys/net/ipv4/ip_forward
 +
}}
  
= Sharing via WLAN =
+
== See Also ==
 +
* [[Internet Share]]
 +
* [[Simple stateful firewall HOWTO]]
 +
* [[NAT'ing firewall - Share your broadband connection]]
 +
* [[Wireless Setup]]
 +
* [[USB 3G Modem]]

Revision as of 21:27, 7 March 2013


Requirements

Before proceeding, you must make sure:

  1. You must have a working PPP connection.
  2. You must have an extra Ethernet interface card in your computer with which to share your connection.

Installing

The following packages must be installed from the official repositories for both Wired and Wireless sharing:

  • iptables: for controlling packets in your network.
  • dnsmasq: for acting as a DHCP and DNS caching server.
  • bridge-utils: for setting up a network bridge.

Depending on whether you want to share a wireless or wired connection, you also have to install:

Sharing via Wired Ethernet

  • Set the PPP connection up.
You can assign an IP address to the interface as usual, by running (as root):
# ip addr add 192.168.0.254 dev eth0
  • Set the kernel to router mode. This is done by running:
# echo 1 > /proc/sys/net/ipv4/ip_forward
  • Configure dnsmasqd. Make the following changes to /etc/dnsmasq.conf (uncomment if necessary):
/etc/dnsmasq.conf
domain-needed
bogus-priv
interface=eth0 # change to your chosen interface
dhcp-range=192.168.0.1,192.168.0.100,12h
  • Start the dnsmasq daemon.
  • Finally, set firewall to forward connections to and from the Internet for clients connecting to your WLAN. This is done by issuing:
# iptables -t nat -A POSTROUTING -o ppp0 -j MASQUERADE
In the above the ppp0 interface is the used PPP interface, you can substitute it for yours if needed.
  • You are done! Happy surfing!
Warning: The previous configuration has no security options enabled. If you are using a firewall, you should adapt this documentation to suit your needs. Same applies also to setting up keys for WLAN interface.

Network Bridge

Let's assume your PPP connection is on eth0, and you want to share the connection on eth1 and eth2.

# ip addr add 0.0.0.0 dev eth1  # remove IP from eth0
# ip link set eth1 up           # ensure the interface is up
# ip addr add 0.0.0.0 dev eth2  # remove IP from eth1
# ip link set eth2 up           # ensure the interface is up
# brctl addbr br0               # create br0 node
# brctl addif br0 eth1          # add eth0 to bridge br0
# brctl addif br0 eth2          # add eth1 to bridge br0
# ip addr add 192.168.0.254 dev br0

change your interface in dnsmasq.conf to br0:

interface=br0 

and restart the dnsmasq daemon.

Now you should be able to connect to the internet using eth1 or eth2.

Sharing via WLAN

Instructions

  • Set up the PPP connection.
  • Set up the WLAN connection: choose an SSID and select Ad-hoc as network type. In the following it is assumed that you are using the wlan0 interface.
Set the wlan0 interface up address for example 192.168.0.254. Setting up the interface is usually done by running:
# iwconfig wlan0 essid "MyFreeWlan" mode ad-hoc
After that you can assign an IP address to the interface as usual, by running:
# ip addr add 192.168.0.254 dev wlan0
Please note that different wlan cards may be configured differently and one should adapt this documentation accordingly.
  • Set the kernel to router mode. This is done by running:
# echo 1 > /proc/sys/net/ipv4/ip_forward
  • Configure dnsmasq. Make the following changes to /etc/dnsmasq.conf (uncomment if necessary):
etc/dnsmasq.conf
domain-needed
bogus-priv
interface=wlan0    # change to your interface
dhcp-range=192.168.0.1,192.168.0.100,12h
  • Start the dnsmasq daemon.
  • Finally, set firewall to forward connections to and from the Internet for clients connecting to your WLAN. This is done by issuing:
# iptables -t nat -A POSTROUTING -o ppp0 -j MASQUERADE
In the above the ppp0 interface is assumed to be the used PPP interface, you can substitute it for yours if needed.
  • You are done! Happy surfing!
Warning: The previous configuration has no security options enabled! If you are using firewall, you should adapt this documentation to suit your needs. Same applies also to setting up keys for wlan interface.

Sharing Script

A quick script for sharing eth0 over wlan0 on an ad-hoc network.

ethoverwlan.sh
#!/bin/bash

iwconfig wlan0 mode ad-hoc
iwconfig wlan0 essid proxywlan
ip addr add 192.168.0.254 dev wlan0
ip link set wlan0 up
iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE
echo 1 > /proc/sys/net/ipv4/ip_forward

See Also