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Gentoo Linux alpha Manual: Configuração de rede
Handbook:Alpha/Networking/Introdução
Handbook:Alpha/Networking/Avançado
Network modules
Netifrc scripts now support modular networking scripts, which means support for new interface types and configuration modules can easily be added while keeping compatibility with existing ones.
Modules load by default if the package they need is installed. If users specify a module here that doesn't have its package installed then they get an error stating which package they need to install. Ideally, the modules setting is only used when two or more packages are installed that supply the same service and one needs to be preferred over the other.
All settings discussed here are stored in /etc/conf.d/net unless otherwise specified.
/etc/conf.d/netModule definitions# Prefer ifconfig over iproute2 modules="ifconfig" # You can also specify other modules for an interface # In this case we prefer pump over dhcpcd modules_eth0="pump" # You can also specify which modules not to use - for example you may be # using a supplicant or linux-wlan-ng to control wireless configuration but # you still want to configure network settings per ESSID associated with. modules="!iwconfig"
Interface handlers
We provide two interface handlers presently: ifconfig and iproute2. Only one of these is needed to do any kind of network configuration.
Both are installed by default as part of the system profile. iproute2 is the more powerful and flexible package.
/etc/conf.d/netiproute2 is installed but still prefer ifconfig# To prefer ifconfig over iproute2 if both are installed as openrc prefers # to use iproute2 then modules="ifconfig"
As both ifconfig and iproute2 do very similar things we allow their basic configuration to work with each other. For example both the below code snippet work regardless of which module the user is using.
/etc/conf.d/netExample different approaches for configurationconfig_eth0="192.168.0.2/24" config_eth0="192.168.0.2 netmask 255.255.255.0" # We can also specify broadcast config_eth0="192.168.0.2/24 brd 192.168.0.255" config_eth0="192.168.0.2 netmask 255.255.255.0 broadcast 192.168.0.255"
DHCP
DHCP is a means of obtaining network information (IP address, DNS servers, Gateway, etc) from a DHCP server. This means that if there is a DHCP server running on the network, the user just has to tell each client to use DHCP and it sets up the network all by itself. Of course, the user will have to configure for other things like wireless, PPP or other things if required before he can use DHCP.
DHCP can be provided by dhclient, dhcpcd, or pump. Each DHCP module has its pros and cons - here is a quick run down:
| DHCP module | Package | Pros | Cons |
|---|---|---|---|
| dhclient | net-misc/dhcp | Made by ISC, the same people who make the BIND DNS software. Very configurable | Configuration is overly complex, software is quite bloated, cannot get NTP servers from DHCP, does not send hostname by default |
| dhcpcd | net-misc/dhcpcd | Long time Gentoo default, no reliance on outside tools, actively developed by Gentoo | Can be slow at times, does not yet daemonize when lease is infinite |
| pump | net-misc/pump | Lightweight, no reliance on outside tools | No longer maintained upstream, unreliable, especially over modems, cannot get NIS servers from DHCP |
If more than one DHCP client is installed, specify which one to use - otherwise we default to dhcpcd if available.
To send specific options to the DHCP module, use module_eth0="..." (change module to the DHCP module being used - i.e. dhcpcd_eth0).
We try to make DHCP relatively agnostic - as such we support the following commands using the dhcp_eth0 variable. The default is not to set any of them:
release- Releases the IP address for re-use.
nodns- Don't overwrite /etc/resolv.conf
nontp- Don't overwrite /etc/ntp.conf
nonis- Don't overwrite /etc/yp.conf
/etc/conf.d/netSample DHCP configuration# Only needed if you have more than one DHCP module installed modules="dhcpcd" config_eth0="dhcp" dhcpcd_eth0="-t 10" # Timeout after 10 seconds dhcp_eth0="release nodns nontp nonis" # Only get an address
dhcpcd and pump send the current hostname to the DHCP server by default so this does not need to be specified anymore.
ADSL with PPPoE/PPPoA
First install the ADSL software:
root #emerge --ask net-dialup/pppSecond, create the PPP net script and the net script for the Ethernet interface to be used by PPP:
root #ln -s /etc/init.d/net.lo /etc/init.d/net.ppp0
root #ln -s /etc/init.d/net.lo /etc/init.d/net.eth0Be sure to set rc_depend_strict to YES in /etc/rc.conf.
Now we need to configure /etc/conf.d/net.
/etc/conf.d/netA basic PPPoE setupconfig_eth0=null (Specify the ethernet interface) config_ppp0="ppp" link_ppp0="eth0" (Specify the ethernet interface) plugins_ppp0="pppoe" username_ppp0='user' password_ppp0='password' pppd_ppp0=" noauth defaultroute usepeerdns holdoff 3 child-timeout 60 lcp-echo-interval 15 lcp-echo-failure 3 noaccomp noccp nobsdcomp nodeflate nopcomp novj novjccomp" rc_net_ppp0_need="net.eth0"
It is also possible to set the password in /etc/ppp/pap-secrets.
/etc/ppp/pap-secretsSample pap-secrets# The * is important "username" * "password"
If PPPoE is used with a USB modem then make sure to emerge br2684ctl. Please read /usr/portage/net-dialup/speedtouch-usb/files/README for information on how to properly configure it.
Please carefully read the section on ADSL and PPP in /usr/share/doc/netifrc-*/net.example.bz2. It contains many more detailed explanations of all the settings any particular PPP setup will likely need.
APIPA (Automatic Private IP Addressing)
APIPA tries to find a free address in the range 169.254.0.0-169.254.255.255 by arping a random address in that range on the interface. If no reply is found then we assign that address to the interface.
This is only useful for LANs where there is no DHCP server and the system doesn't connect directly to the Internet and all other computers use APIPA.
For APIPA support, emerge net-misc/iputils with the arping USE flag or net-analyzer/arping.
/etc/conf.d/netAPIPA configuration# Try DHCP first - if that fails then fallback to APIPA config_eth0="dhcp" fallback_eth0="apipa" # Just use APIPA config_eth0="apipa"
Bonding
Bonding is used to increase network bandwidth or to improve resiliency in face of hardware failures. If a system has two network cards going to the same network, then the administrator can bond them together so the applications see just one interface but they really use both network cards.
There are many ways to configure bonding. Some of them, such as the 802.3ad LACP mode, require support and additional configuration of the network switch. For a reference of the individual options, please refer to the local copy of /usr/src/linux/Documentation/networking/bonding.txt.
First, clear the configuration of the participating interfaces:
/etc/conf.d/netClearing interface configurationconfig_eth0="null" config_eth1="null" config_eth2="null"
Next, define the bonding between the interfaces:
/etc/conf.d/netDefine the bondingslaves_bond0="eth0 eth1 eth2" config_bond0="192.168.100.4/24" # Pick a correct mode and additional configuration options which suit your needs mode_bond0="balance-alb"
Remove the net.eth* services from the runlevels, create a net.bond0 one and add that one to the correct runlevel.
Bridging (802.1d support)
Bridging is used to join networks together. For example, a system may have a server that connects to the Internet via an ADSL modem and a wireless access card to enable other computers to connect to the Internet via the ADSL modem. It is possible to create a bridge to join the two interfaces together.
/etc/conf.d/netBridge configuration# Configure the bridge - "man brctl" for more details bridge_forward_delay_br0=0 bridge_hello_time_br0=200 bridge_stp_state_br0=1 # To add ports to bridge br0 bridge_br0="eth0 eth1" # You need to configure the ports to null values so dhcp does not get started config_eth0="null" config_eth1="null" # Finally give the bridge an address - you could use DHCP as well config_br0="192.168.0.1/24" # Depend on eth0 and eth1 as they may require extra configuration rc_net_br0_need="net.eth0 net.eth1"
For using some bridge setups, consult the variable name documentation.
When bridging using IPv6, SLAAC requires STP to be set to
1 as seen in the example above.MAC address
It is possible to change the MAC address of the interfaces through the network configuration file too.
/etc/conf.d/netMAC Address change example# To set the MAC address of the interface mac_eth0="00:11:22:33:44:55" # To randomize the last 3 bytes only mac_eth0="random-ending" # To randomize between the same physical type of connection (e.g. fibre, # copper, wireless) , all vendors mac_eth0="random-samekind" # To randomize between any physical type of connection (e.g. fibre, copper, # wireless) , all vendors mac_eth0="random-anykind" # Full randomization - WARNING: some MAC addresses generated by this may # NOT act as expected mac_eth0="random-full"
Tunneling
Tunneling does not require any additional software to be installed as the interface handler can do it.
/etc/conf.d/netTunneling configuration# For GRE tunnels iptunnel_vpn0="mode gre remote 207.170.82.1 key 0xffffffff ttl 255" # For IPIP tunnels iptunnel_vpn0="mode ipip remote 207.170.82.2 ttl 255" # To configure the interface config_vpn0="192.168.0.2 peer 192.168.1.1"
VLAN (802.1q support)
For VLAN support, make sure that sys-apps/iproute2 is installed and ensure that iproute2 is used as configuration module rather than ifconfig.
Virtual LAN is a group of network devices that behave as if they were connected to a single network segment - even though they may not be. VLAN members can only see members of the same VLAN even though they may share the same physical network.
To configure VLANs, first specify the VLAN numbers in /etc/conf.d/net like so:
/etc/conf.d/netSpecifying VLAN numbersvlans_eth0="1 2"
Next, configure the interface for each VLAN:
/etc/conf.d/netInterface configuration for each VLANconfig_eth0_1="172.16.3.1 netmask 255.255.254.0" routes_eth0_1="default via 172.16.3.254" config_eth0_2="172.16.2.1 netmask 255.255.254.0" routes_eth0_2="default via 172.16.2.254"
VLAN-specific configurations are handled by vconfig like so:
/etc/conf.d/netConfiguring the VLANsvlan1_name="vlan1" vlan1_ingress="2:6 3:5" eth0_vlan1_egress="1:2"
For using some VLAN setups, consult the variable name documentation.
Introduction
Wireless networking on Linux is usually pretty straightforward. There are three ways of configuring wifi: graphical clients, text-mode interfaces, and command-line interfaces.
The easiest way is to use a graphical client once a desktop environment is installed. Most graphical clients, such as wicd and NetworkManager, are pretty self-explanatory. They offer a handy point-and-click interface that gets users on a network in just a few seconds.
Both NetworkManager and wicd offer text-mode interface utilities in addition to the main graphical interface. Emerge either the net-misc/networkmanager or net-misc/wicd package with the
ncurses USE flag enabled. The nmtui or wicd-curses utilities are particularly useful for folks who do not use a X or Wayland based desktop environment, but still desire an easy-to-use tool that does not require hand-editing configuration files.Wireless can also be configured from the command line by editing a few configuration files. This takes a bit more time to setup, but it also requires the fewest packages to download and install. Since the graphical clients are mostly self-explanatory (with helpful screen shots at their home pages), we'll focus on the command line alternatives.
There are three tools that support command-line driven wireless configurations: net-wireless/iw, net-wireless/wireless-tools and net-wireless/wpa_supplicant. Of these three, net-wireless/wpa_supplicant is the preferred one. The important thing to remember is that wireless networks are configured on a global basis and not an interface basis.
The net-wireless/iw software, the successor of net-wireless/wireless-tools, supports nearly all cards and drivers, but it cannot connect to WPA-only Access Points. If the networks only offer WEP encryption or are completely open, then net-wireless/iw beats the other package over simplicity.
Some wireless cards are deactivated by default. To activate them, please consult the hardware documentation. Some of these cards can be unblocked using the rfkill application. If that is the case, use rfkill list to see the available cards and rfkill unblock INDEX to activate the wireless functionality. If not, then the wireless card might need to be unlocked through a button, switch or special key combination on the laptop.
WPA supplicant
The WPA supplicant project provides a package that allows users to connect to WPA enabled access points.
root #emerge --ask net-wireless/wpa_supplicantIt is necessary to have CONFIG_PACKET enabled in the kernel for wpa_supplicant to work. To see if it is enabled on the current kernel, try:
root #zgrep CONFIG_PACKET /proc/config.gz
root #grep CONFIG_PACKET /usr/src/linux/.config
Depending on the USE flags, wpa_supplicant can install a graphical interface written in Qt5, which will integrate nicely with KDE. To get it, enable
USE="qt5" for the net-wireless/wpa_supplicant package.Next, configure /etc/conf.d/net so that the wpa_supplicant module is preferred over wireless-tools (if both are installed, wireless-tools is the default).
/etc/conf.d/netForce the use of wpa_supplicant# Prefer wpa_supplicant over wireless-tools modules="wpa_supplicant"
When using the host-ap driver it is necessary to put the card in Managed mode before it can be used with wpa_supplicant correctly. This can be achieved by setting
iwconfig_eth0="mode managed" in /etc/conf.d/net.Next configure wpa_supplicant itself (which is a bit more tricky depending on how secure the Access Points are). The below example is taken and simplified from /usr/share/doc/wpa_supplicant-<version>/wpa_supplicant.conf.gz which ships with wpa_supplicant.
/etc/wpa_supplicant/wpa_supplicant.confSomewhat simplified example# The below line not be changed otherwise wpa_supplicant refuses to work ctrl_interface=/var/run/wpa_supplicant # Ensure that only root can read the WPA configuration ctrl_interface_group=0 # Let wpa_supplicant take care of scanning and AP selection ap_scan=1 # Simple case: WPA-PSK, PSK as an ASCII passphrase, allow all valid ciphers network={ ssid="simple" psk="very secret passphrase" # The higher the priority the sooner we are matched priority=5 } # Same as previous, but request SSID-specific scanning (for APs that reject # broadcast SSID) network={ ssid="second ssid" scan_ssid=1 psk="very secret passphrase" priority=2 } # Only WPA-PSK is used. Any valid cipher combination is accepted network={ ssid="example" proto=WPA key_mgmt=WPA-PSK pairwise=CCMP TKIP group=CCMP TKIP WEP104 WEP40 psk=06b4be19da289f475aa46a33cb793029d4ab3db7a23ee92382eb0106c72ac7bb priority=2 } # Plaintext connection (no WPA, no IEEE 802.1X) network={ ssid="plaintext-test" key_mgmt=NONE } # Shared WEP key connection (no WPA, no IEEE 802.1X) network={ ssid="static-wep-test" key_mgmt=NONE # Keys in quotes are ASCII keys wep_key0="abcde" # Keys specified without quotes are hex keys wep_key1=0102030405 wep_key2="1234567890123" wep_tx_keyidx=0 priority=5 } # Shared WEP key connection (no WPA, no IEEE 802.1X) using Shared Key # IEEE 802.11 authentication network={ ssid="static-wep-test2" key_mgmt=NONE wep_key0="abcde" wep_key1=0102030405 wep_key2="1234567890123" wep_tx_keyidx=0 priority=5 auth_alg=SHARED } # IBSS/ad-hoc network with WPA-None/TKIP network={ ssid="test adhoc" mode=1 proto=WPA key_mgmt=WPA-NONE pairwise=NONE group=TKIP psk="secret passphrase" }
Wireless tools
Initial setup and managed mode
The wireless tools project provides a generic way to configure basic wireless interfaces up to the WEP security level. While WEP is a weak security method it's still prevalent in the world.
Wireless tools configuration is controlled by a few main variables. The sample configuration file below should describe all that is needed. One thing to bear in mind is that no configuration means "connect to the strongest unencrypted Access Point" - wireless tools will always try and connect the system to something.
root #emerge --ask net-wireless/wireless-toolsAlthough net-wireless/iw is the current tool for the wireless stack, net-misc/netifrc does not work with the new commands. net-wireless/wireless-tools must be used with netifrc. For more information consult the variable name documentation.
/etc/conf.d/netSample iwconfig setup# Prefer iwconfig over wpa_supplicant modules="iwconfig" # Configure WEP keys for Access Points called ESSID1 and ESSID2 # You may configure up to 4 WEP keys, but only 1 can be active at # any time so we supply a default index of [1] to set key [1] and then # again afterwards to change the active key to [1] # We do this incase you define other ESSID's to use WEP keys other than 1 # # Prefixing the key with s: means it's an ASCII key, otherwise a HEX key # # enc open specified open security (most secure) # enc restricted specified restricted security (least secure) key_ESSID1="[1] s:yourkeyhere key [1] enc open" key_ESSID2="[1] aaaa-bbbb-cccc-dd key [1] enc restricted" # The below only work when we scan for available Access Points # Sometimes more than one Access Point is visible so we need to # define a preferred order to connect in preferred_aps="'ESSID1' 'ESSID2'"
Fine-tune AP selection
It is possible to add some extra options to fine-tune the AP selection, but these are not required.
One way is to configure the system so it only connects to preferred APs. By default if everything configured has failed and wireless-tools can connect to an unencrypted Access Point then it will. This can be controlled by the associate_order variable. Here's a table of values and how they control this.
| Value | Description |
|---|---|
| any | Default behavior. |
| preferredonly | Only connect to visible APs in the preferred list. |
| forcepreferred | Forceably connect to APs in the preferred order if they are not found in a scan. |
| forcepreferredonly | Do not scan for APs - instead just try to connect to each one in order. |
| forceany | Same as forcepreferred + connect to any other available AP. |
There is also the blacklist_aps and unique_ap selection. blacklist_aps works in a similar way to preferred_aps. unique_ap is a yes or no value that says if a second wireless interface can connect to the same Access Point as the first interface.
/etc/conf.d/netblacklist_aps and unique_ap example# Sometimes you never want to connect to certain access points blacklist_aps="'ESSID3' 'ESSID4'" # If you have more than one wireless card, you can say if you want # to allow each card to associate with the same Access Point or not # Values are "yes" and "no" # Default is "yes" unique_ap="yes"
Ad-hoc and master modes
To set the system up as an ad-hoc node when it fails to connect to any Access Point in managed mode, use this as a fallback:
/etc/conf.d/netFallback to ad-hoc modeadhoc_essid_eth0="This Adhoc Node"
It is also possible to connect to ad-hoc networks, or to run the system in master mode so it becomes an access point itself.
/etc/conf.d/netSample ad-hoc/master configuration# Set the mode - can be managed (default), ad-hoc or master # Not all drivers support all modes mode_eth0="ad-hoc" # Set the ESSID of the interface # In managed mode, this forces the interface to try and connect to the # specified ESSID and nothing else essid_eth0="This Adhoc Node" # We use channel 3 if you don't specify one channel_eth0="9"
An important resource about channel selection is the BSD wavelan documentation found at the NetBSD documentation. There are 14 channels possible; We are told that channels 1-11 are legal for North America, channels 1-13 for most of Europe, channels 10-13 for France, and only channel 14 for Japan. If in doubt, please refer to the documentation that came with the card or access point. Make sure that the channel selected is the same channel the access point (or the other card in an ad-hoc network) is on. The default for cards sold in North America and most of Europe is 3; the default for cards sold in France is 11, and the default for cards sold in Japan is 14.
Troubleshooting wireless tools
There are some more variables that can help to get the wireless up and running due to driver or environment problems. Here's a table of other things that can be tried.
| Variable name | Default value | Description |
|---|---|---|
| iwconfig_eth0 | See the iwconfig man page for details on what to send iwconfig. | |
| iwpriv_eth0 | See the iwpriv man page for details on what to send iwpriv. | |
| sleep_scan_eth0 | 0 | The number of seconds to sleep before attempting to scan. This is needed when the driver/firmware needs more time to active before it can be used. |
| sleep_associate_eth0 | 5 | The number of seconds to wait for the interface to associate with the Access Point before moving onto the next one. |
| associate_test_eth0 | MAC | Some drivers do not reset the MAC address associated with an invalid one when they lose or attempt association. Some drivers do not reset the quality level when they lose or attempt association. Valid settings are MAC, quality and all. |
| scan_mode_eth0 | Some drivers have to scan in ad-hoc mode, so if scanning fails try setting ad-hoc here. | |
| iwpriv_scan_pre_eth0 | Sends some iwpriv commands to the interface before scanning. See the iwpriv man page for more details. | |
| iwpriv_scan_post_eth0 | Sends some iwpriv commands to the interface after scanning. See the iwpriv man page for more details. |
Defining network configuration per ESSID
In this section, we show how to configure network settings based on the ESSID. For instance, with the wireless network with ESSID ESSID1 configure a static IP address while ESSID ESSID2 uses DHCP.
This works with both wpa_supplicant as well as wireless-tools
Please consult the variable name documentation.
/etc/conf.d/netoverride network settings per ESSIDconfig_ESSID1="192.168.0.3/24 brd 192.168.0.255" routes_ESSID1="default via 192.168.0.1" config_ESSID2="dhcp" fallback_ESSID2="192.168.3.4/24" fallback_route_ESSID2="default via 192.168.3.1" # We can define nameservers and other things too # NOTE: DHCP will override these unless it's told not to dns_servers_ESSID1="192.168.0.1 192.168.0.2" dns_domain_ESSID1="some.domain" dns_search_domains_ESSID1="search.this.domain search.that.domain" # You override by the MAC address of the Access Point # This handy if you goto different locations that have the same ESSID config_001122334455="dhcp" dhcpcd_001122334455="-t 10" dns_servers_001122334455="192.168.0.1 192.168.0.2"
Handbook:Alpha/Networking/Estendendo
Handbook:Alpha/Networking/Dinâmico
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