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Sun Oct 23 09:46:14 2011 UTC (2 years, 10 months ago) by swift
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Bug #387697 - OpenRC prefers iproute2 over ifconfig by default. Thanks to Grant Edwards for reporting

1 <?xml version="1.0" encoding="UTF-8"?>
2 <!DOCTYPE sections SYSTEM "/dtd/book.dtd">
3
4 <!-- The content of this document is licensed under the CC-BY-SA license -->
5 <!-- See http://creativecommons.org/licenses/by-sa/2.5 -->
6
7 <!-- $Header: /var/cvsroot/gentoo/xml/htdocs/doc/en/handbook/hb-net-modules.xml,v 1.26 2011/08/14 16:12:13 swift Exp $ -->
8
9 <sections>
10
11 <abstract>
12 Gentoo provides you flexible networking - here you are told about choosing
13 different DHCP clients, setting up bonding, bridging, VLANs and more.
14 </abstract>
15
16 <version>10</version>
17 <date>2011-10-23</date>
18
19 <section>
20 <title>Network Modules</title>
21 <body>
22
23 <p>
24 We now support modular networking scripts, which means we can easily add support
25 for new interface types and configuration modules while keeping compatibility
26 with existing ones.
27 </p>
28
29 <p>
30 Modules load by default if the package they need is installed. If you specify a
31 module here that doesn't have its package installed then you get an error
32 stating which package you need to install. Ideally, you only use the modules
33 setting when you have two or more packages installed that supply the same
34 service and you need to prefer one over the other.
35 </p>
36
37 <note>
38 All settings discussed here are stored in <path>/etc/conf.d/net</path> unless
39 otherwise specified.
40 </note>
41
42 <pre caption="Module preference">
43 <comment># Prefer ifconfig over iproute2</comment>
44 modules="ifconfig"
45
46 <comment># You can also specify other modules for an interface
47 # In this case we prefer pump over dhcpcd</comment>
48 modules_eth0="pump"
49
50 <comment># You can also specify which modules not to use - for example you may be
51 # using a supplicant or linux-wlan-ng to control wireless configuration but
52 # you still want to configure network settings per ESSID associated with.</comment>
53 modules="!iwconfig"
54 </pre>
55
56 </body>
57 </section>
58 <section>
59 <title>Interface Handlers</title>
60 <body>
61
62 <p>
63 We provide two interface handlers presently: <c>ifconfig</c> and
64 <c>iproute2</c>. You need one of these to do any kind of network configuration.
65 </p>
66
67 <p>
68 <c>ifconfig</c> is installed by default (the <c>net-tools</c> package is part of
69 the system profile). <c>iproute2</c> is a more powerful and flexible package,
70 but it's not included by default.
71 </p>
72
73 <pre caption="To install iproute2">
74 # <i>emerge sys-apps/iproute2</i>
75
76 <comment># To prefer ifconfig over iproute2 if both are installed as openrc prefers
77 # to use iproute2 then</comment>
78 modules="ifconfig"
79 </pre>
80
81 <p>
82 As both <c>ifconfig</c> and <c>iproute2</c> do very similar things we allow
83 their basic configuration to work with each other. For example both the below
84 code snippet work regardless of which module you are using.
85 </p>
86
87 <pre caption="ifconfig and iproute2 examples">
88 config_eth0="192.168.0.2/24"
89 config_eth0="192.168.0.2 netmask 255.255.255.0"
90
91 <comment># We can also specify broadcast</comment>
92 config_eth0="192.168.0.2/24 brd 192.168.0.255"
93 config_eth0="192.168.0.2 netmask 255.255.255.0 broadcast 192.168.0.255"
94 </pre>
95
96 </body>
97 </section>
98 <section id="dhcp">
99 <title>DHCP</title>
100 <body>
101
102 <p>
103 DHCP is a means of obtaining network information (IP address, DNS servers,
104 Gateway, etc) from a DHCP server. This means that if there is a DHCP server
105 running on the network, you just have to tell each client to use DHCP and it
106 sets up the network all by itself. Of course, you will have to configure for
107 other things like wireless, PPP or other things if required before you can use
108 DHCP.
109 </p>
110
111 <p>
112 DHCP can be provided by <c>dhclient</c>, <c>dhcpcd</c>, or <c>pump</c>. Each
113 DHCP module has its pros and cons - here's a quick run down.
114 </p>
115
116 <table>
117 <tr>
118 <th>DHCP Module</th>
119 <th>Package</th>
120 <th>Pros</th>
121 <th>Cons</th>
122 </tr>
123 <tr>
124 <ti><c>dhclient</c></ti>
125 <ti><c>net-misc/dhcp</c></ti>
126 <ti>
127 Made by ISC, the same people who make the BIND DNS software. Very
128 configurable
129 </ti>
130 <ti>
131 Configuration is overly complex, software is quite bloated, cannot get
132 NTP servers from DHCP, does not send hostname by default
133 </ti>
134 </tr>
135 <tr>
136 <ti><c>dhcpcd</c></ti>
137 <ti><c>net-misc/dhcpcd</c></ti>
138 <ti>
139 Long time Gentoo default, no reliance on outside tools, actively developed
140 by Gentoo
141 </ti>
142 <ti>Can be slow at times, does not yet daemonize when lease is infinite</ti>
143 </tr>
144 <tr>
145 <ti><c>pump</c></ti>
146 <ti><c>net-misc/pump</c></ti>
147 <ti>
148 Lightweight, no reliance on outside tools
149 </ti>
150 <ti>
151 No longer maintained upstream, unreliable, especially over modems, cannot
152 get NIS servers from DHCP
153 </ti>
154 </tr>
155 </table>
156
157 <p>
158 If you have more than one DHCP client installed, you need to specify which one
159 to use - otherwise we default to <c>dhcpcd</c> if available.
160 </p>
161
162 <p>
163 To send specific options to the DHCP module, use <c>module_eth0="..."</c>
164 <e>(change module to the DHCP module you're using - i.e. <c>dhcpcd_eth0</c>)</e>.
165 </p>
166
167 <p>
168 We try and make DHCP relatively agnostic - as such we support the following
169 commands using the <c>dhcp_eth0</c> variable. The default is not to set any of
170 them:
171 </p>
172
173 <ul>
174 <li><c>release</c> - releases the IP address for re-use</li>
175 <li><c>nodns</c> - don't overwrite <path>/etc/resolv.conf</path></li>
176 <li><c>nontp</c> - don't overwrite <path>/etc/ntp.conf</path></li>
177 <li><c>nonis</c> - don't overwrite <path>/etc/yp.conf</path></li>
178 </ul>
179
180 <pre caption="Sample DHCP configuration in /etc/conf.d/net">
181 <comment># Only needed if you have more than one DHCP module installed</comment>
182 modules="dhcpcd"
183
184 config_eth0="dhcp"
185 dhcpcd_eth0="-t 10" <comment># Timeout after 10 seconds</comment>
186 dhcp_eth0="release nodns nontp nonis" <comment># Only get an address</comment>
187 </pre>
188
189 <note>
190 <c>dhcpcd</c> and <c>pump</c> send the current hostname to the
191 DHCP server by default so you don't need to specify this anymore.
192 </note>
193
194 </body>
195 </section>
196 <section>
197 <title>ADSL with PPPoE/PPPoA</title>
198 <body>
199
200 <p>
201 First we need to install the ADSL software.
202 </p>
203
204 <pre caption="Install the ppp package">
205 # <i>emerge net-dialup/ppp</i>
206 </pre>
207
208 <p>
209 Second, create the PPP net script and the net script for the ethernet interface
210 to be used by PPP:
211 </p>
212
213 <pre caption="Creating the PPP and ethernet scripts">
214 # <i>ln -s /etc/init.d/net.lo /etc/init.d/net.ppp0</i>
215 # <i>ln -s /etc/init.d/net.lo /etc/init.d/net.eth0</i>
216 </pre>
217
218 <p>
219 Be sure to set <c>rc_depend_strict</c> to "YES" in <path>/etc/rc.conf</path>.
220 </p>
221
222 <p>
223 Now we need to configure <path>/etc/conf.d/net</path>.
224 </p>
225
226 <pre caption="A basic PPPoE setup">
227 config_eth0=null <comment>(Specify your ethernet interface)</comment>
228 config_ppp0="ppp"
229 link_ppp0="eth0" <comment>(Specify your ethernet interface)</comment>
230 plugins_ppp0="pppoe"
231 username_ppp0='user'
232 password_ppp0='password'
233 pppd_ppp0="
234 noauth
235 defaultroute
236 usepeerdns
237 holdoff 3
238 child-timeout 60
239 lcp-echo-interval 15
240 lcp-echo-failure 3
241 noaccomp noccp nobsdcomp nodeflate nopcomp novj novjccomp"
242
243 rc_need_ppp0="net.eth0"
244 </pre>
245
246 <p>
247 You can also set your password in <path>/etc/ppp/pap-secrets</path>.
248 </p>
249
250 <pre caption="Sample /etc/ppp/pap-secrets">
251 <comment># The * is important</comment>
252 "username" * "password"
253 </pre>
254
255 <p>
256 If you use PPPoE with a USB modem you'll need to emerge <c>br2684ctl</c>. Please
257 read <path>/usr/portage/net-dialup/speedtouch-usb/files/README</path> for
258 information on how to properly configure it.
259 </p>
260
261 <impo>
262 Please carefully read the section on ADSL and PPP in
263 <path>/usr/share/doc/openrc-0.8.3-r1/net.example.bz2</path>. It contains many
264 more detailed explanations of all the settings your particular PPP setup will
265 likely need. Of course, change <c>0.8.3-r1</c> with the version of OpenRC
266 installed on your system.
267 </impo>
268
269 </body>
270 </section>
271 <section id="apipa">
272 <title>APIPA (Automatic Private IP Addressing)</title>
273 <body>
274
275 <p>
276 APIPA tries to find a free address in the range 169.254.0.0-169.254.255.255 by
277 arping a random address in that range on the interface. If no reply is found
278 then we assign that address to the interface.
279 </p>
280
281 <p>
282 This is only useful for LANs where there is no DHCP server and you don't connect
283 directly to the internet and all other computers use APIPA.
284 </p>
285
286 <p>
287 For APIPA support, emerge <c>net-misc/iputils</c> or <c>net-analyzer/arping</c>.
288 </p>
289
290 <pre caption="APIPA configuration in /etc/conf.d/net">
291 <comment># Try DHCP first - if that fails then fallback to APIPA</comment>
292 config_eth0="dhcp"
293 fallback_eth0="apipa"
294
295 <comment># Just use APIPA</comment>
296 config_eth0="apipa"
297 </pre>
298
299 </body>
300 </section>
301 <section>
302 <title>Bonding</title>
303 <body>
304
305 <p>
306 For link bonding/trunking emerge <c>net-misc/ifenslave</c>.
307 </p>
308
309 <p>
310 Bonding is used to increase network bandwidth. If you have two network cards
311 going to the same network, you can bond them together so your applications see
312 just one interface but they really use both network cards.
313 </p>
314
315 <pre caption="bonding configuration in /etc/conf.d/net">
316 <comment># To bond interfaces together</comment>
317 slaves_bond0="eth0 eth1 eth2"
318
319 <comment># You may not want to assign an IP to the bonded interface</comment>
320 config_bond0="null"
321
322 <comment># Depend on eth0, eth1 and eth2 as they may require extra configuration</comment>
323 rc_need_bond0="net.eth0 net.eth1 net.eth2"
324 </pre>
325
326 </body>
327 </section>
328 <section>
329 <title>Bridging (802.1d support)</title>
330 <body>
331
332 <p>
333 For bridging support emerge <c>net-misc/bridge-utils</c>.
334 </p>
335
336 <p>
337 Bridging is used to join networks together. For example, you may have a server
338 that connects to the internet via an ADSL modem and a wireless access card to
339 enable other computers to connect to the internet via the ADSL modem. You could
340 create a bridge to join the two interfaces together.
341 </p>
342
343 <pre caption="Bridge configuration in /etc/conf.d/net">
344 <comment># Configure the bridge - "man brctl" for more details</comment>
345 brctl_br0="setfd 0" "sethello 0" "stp off"
346
347 <comment># To add ports to bridge br0</comment>
348 bridge_br0="eth0 eth1"
349
350 <comment># You need to configure the ports to null values so dhcp does not get started</comment>
351 config_eth0="null"
352 config_eth1="null"
353
354 <comment># Finally give the bridge an address - you could use DHCP as well</comment>
355 config_br0="192.168.0.1/24"
356
357 <comment># Depend on eth0 and eth1 as they may require extra configuration</comment>
358 rc_need_br0="net.eth0 net.eth1"
359 </pre>
360
361 <impo>
362 For using some bridge setups, you may need to consult the <uri
363 link="?part=4&amp;chap=2#variable_name">variable name</uri> documentation.
364 </impo>
365
366 </body>
367 </section>
368 <section>
369 <title>MAC Address</title>
370 <body>
371
372 <p>
373 If you need to, you can change the MAC address of your interfaces through
374 the network configuration file too.
375 </p>
376
377 <pre caption="MAC Address change example">
378 <comment># To set the MAC address of the interface</comment>
379 mac_eth0="00:11:22:33:44:55"
380
381 <comment># To randomize the last 3 bytes only</comment>
382 mac_eth0="random-ending"
383
384 <comment># To randomize between the same physical type of connection (e.g. fibre,
385 # copper, wireless) , all vendors</comment>
386 mac_eth0="random-samekind"
387
388 <comment># To randomize between any physical type of connection (e.g. fibre, copper,
389 # wireless) , all vendors</comment>
390 mac_eth0="random-anykind"
391
392 <comment># Full randomization - WARNING: some MAC addresses generated by this may
393 # NOT act as expected</comment>
394 mac_eth0="random-full"
395 </pre>
396
397 </body>
398 </section>
399 <section>
400 <title>Tunnelling</title>
401 <body>
402
403 <p>
404 You don't need to emerge anything for tunnelling as the interface handler can do
405 it for you.
406 </p>
407
408 <pre caption="Tunnelling configuration in /etc/conf.d/net">
409 <comment># For GRE tunnels</comment>
410 iptunnel_vpn0="mode gre remote 207.170.82.1 key 0xffffffff ttl 255"
411
412 <comment># For IPIP tunnels</comment>
413 iptunnel_vpn0="mode ipip remote 207.170.82.2 ttl 255"
414
415 <comment># To configure the interface</comment>
416 config_vpn0="192.168.0.2 peer 192.168.1.1"
417 </pre>
418
419 </body>
420 </section>
421 <section>
422 <title>VLAN (802.1q support)</title>
423 <body>
424
425 <p>
426 For VLAN support, emerge <c>net-misc/vconfig</c>.
427 </p>
428
429 <p>
430 Virtual LAN is a group of network devices that behave as if they were connected
431 to a single network segment - even though they may not be. VLAN members can only
432 see members of the same VLAN even though they may share the same physical
433 network.
434 </p>
435
436 <pre caption="VLAN configuration in /etc/conf.d/net">
437 <comment># Specify the VLAN numbers for the interface like so</comment>
438 <comment># Please ensure your VLAN IDs are NOT zero-padded</comment>
439 vlans_eth0="1 2"
440
441 <comment># You can also configure the VLAN</comment>
442 <comment># see for vconfig man page for more details</comment>
443 vconfig_eth0="set_name_type VLAN_PLUS_VID_NO_PAD"
444 vconfig_vlan1="set_flag 1" "set_egress_map 2 6"
445
446 <comment># Configure the interface as usual</comment>
447 config_vlan1="172.16.3.1 netmask 255.255.254.0"
448 config_vlan2="172.16.2.1 netmask 255.255.254.0"
449 </pre>
450
451 <impo>
452 For using some VLAN setups, you may need to consult the <uri
453 link="?part=4&amp;chap=2#variable_name">variable name</uri> documentation.
454 </impo>
455
456 </body>
457 </section>
458
459 </sections>

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