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Revision 1.22 - (show annotations) (download) (as text)
Sun Apr 8 01:28:11 2007 UTC (7 years, 8 months ago) by nightmorph
Branch: MAIN
Changes since 1.21: +31 -17 lines
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new ADSL/PPP setup, bug 171584. note that i went ahead and did the major version number bump a day or so ahead of the release schedule. i figure, why not. early is better.

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 1.21 2007/01/04 06:03:26 nightmorph 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>8.0</version>
17 <date>2007-04-07</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 iproute2 over ifconfig</comment>
44 modules=( "iproute2" )
45
46 <comment># You can also specify other modules for an interface
47 # In this case we prefer udhcpc over dhcpcd</comment>
48 modules_eth0=( "udhcpc" )
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 the current Gentoo default and it's included in the system
69 profile. <c>iproute2</c> is a more powerful and flexible package, but it's not
70 included by default.
71 </p>
72
73 <pre caption="To install iproute2">
74 # <i>emerge sys-apps/iproute2</i>
75
76 <comment># To prefer iproute2 over ifconfig if both are installed</comment>
77 modules=( "iproute2" )
78 </pre>
79
80 <p>
81 As both <c>ifconfig</c> and <c>iproute2</c> do very similar things we allow
82 their basic configuration to work with each other. For example both the below
83 code snippet work regardless of which module you are using.
84 </p>
85
86 <pre caption="ifconfig and iproute2 examples">
87 config_eth0=( "192.168.0.2/24" )
88 config_eth0=( "192.168.0.2 netmask 255.255.255.0" )
89
90 <comment># We can also specify broadcast</comment>
91 config_eth0=( "192.168.0.2/24 brd 192.168.0.255" )
92 config_eth0=( "192.168.0.2 netmask 255.255.255.0 broadcast 192.168.0.255" )
93 </pre>
94
95 </body>
96 </section>
97 <section id="dhcp">
98 <title>DHCP</title>
99 <body>
100
101 <p>
102 DHCP is a means of obtaining network information (IP address, DNS servers,
103 Gateway, etc) from a DHCP server. This means that if there is a DHCP server
104 running on the network, you just have to tell each client to use DHCP and it
105 sets up the network all by itself. Of course, you will have to configure for
106 other things like wireless, PPP or other things if required before you can use
107 DHCP.
108 </p>
109
110 <p>
111 DHCP can be provided by <c>dhclient</c>, <c>dhcpcd</c>, <c>pump</c> or
112 <c>udhcpc</c>. Each DHCP module has its pros and cons - here's a quick run down.
113 </p>
114
115 <table>
116 <tr>
117 <th>DHCP Module</th>
118 <th>Package</th>
119 <th>Pros</th>
120 <th>Cons</th>
121 </tr>
122 <tr>
123 <ti><c>dhclient</c></ti>
124 <ti><c>net-misc/dhcp</c></ti>
125 <ti>
126 Made by ISC, the same people who make the BIND DNS software. Very
127 configurable
128 </ti>
129 <ti>
130 Configuration is overly complex, software is quite bloated, cannot get
131 NTP servers from DHCP, does not send hostname by default
132 </ti>
133 </tr>
134 <tr>
135 <ti><c>dhcpcd</c></ti>
136 <ti><c>net-misc/dhcpcd</c></ti>
137 <ti>
138 Long time Gentoo default, no reliance on outside tools, actively developed
139 by Gentoo
140 </ti>
141 <ti>Can be slow at times, does not yet daemonize when lease is infinite</ti>
142 </tr>
143 <tr>
144 <ti><c>pump</c></ti>
145 <ti><c>net-misc/pump</c></ti>
146 <ti>
147 Lightweight, no reliance on outside tools
148 </ti>
149 <ti>
150 No longer maintained upstream, unreliable, especially over modems, cannot
151 get NIS servers from DHCP
152 </ti>
153 </tr>
154 <tr>
155 <ti><c>udhcpc</c></ti>
156 <ti><c>net-misc/udhcp</c></ti>
157 <ti>
158 Lightweight - smallest DHCP client around, made for embedded systems
159 </ti>
160 <ti>
161 Unproven - no distro uses it by default, cannot define a timeout beyond 3
162 seconds
163 </ti>
164 </tr>
165 </table>
166
167 <p>
168 If you have more than one DHCP client installed, you need to specify which one
169 to use - otherwise we default to <c>dhcpcd</c> if available.
170 </p>
171
172 <p>
173 To send specific options to the DHCP module, use <c>module_eth0="..."</c>
174 <e>(change module to the DHCP module you're using - i.e. <c>dhcpcd_eth0</c>)</e>.
175 </p>
176
177 <p>
178 We try and make DHCP relatively agnostic - as such we support the following
179 commands using the <c>dhcp_eth0</c> variable. The default is not to set any of
180 them:
181 </p>
182
183 <ul>
184 <li><c>release</c> - releases the IP address for re-use</li>
185 <li><c>nodns</c> - don't overwrite <path>/etc/resolv.conf</path></li>
186 <li><c>nontp</c> - don't overwrite <path>/etc/ntp.conf</path></li>
187 <li><c>nonis</c> - don't overwrite <path>/etc/yp.conf</path></li>
188 </ul>
189
190 <pre caption="Sample DHCP configuration in /etc/conf.d/net">
191 <comment># Only needed if you have more than one DHCP module installed</comment>
192 modules=( "dhcpcd" )
193
194 config_eth0=( "dhcp" )
195 dhcpcd_eth0="-t 10" <comment># Timeout after 10 seconds</comment>
196 dhcp_eth0="release nodns nontp nonis" <comment># Only get an address</comment>
197 </pre>
198
199 <note>
200 <c>dhcpcd</c>, <c>udhcpc</c> and <c>pump</c> send the current hostname to the
201 DHCP server by default so you don't need to specify this anymore.
202 </note>
203
204 </body>
205 </section>
206 <section>
207 <title>ADSL Modem</title>
208 <body>
209
210 <p>
211 First we need to install the ADSL software.
212 </p>
213
214 <pre caption="Install the ppp package">
215 # <i>emerge net-dialup/ppp</i>
216 </pre>
217
218 <note>
219 If you need PPPoA, then you need to use >=<c>baselayout-1.12.x</c>.
220 </note>
221
222 <p>
223 Second, create the PPP net script:
224 </p>
225
226 <pre caption="Creating the PPP net script">
227 # <i>ln -s /etc/init.d/net.lo /etc/init.d/net.ppp0</i>
228 </pre>
229
230 <p>
231 Now we need to configure <path>/etc/conf.d/net</path>.
232 </p>
233
234 <pre caption="A basic PPPoE setup">
235 config_ppp0=( "ppp" )
236 link_ppp0="eth0" <comment>(For PPPoE users; replace eth0 with your actual PPP interface)</comment>
237 plugins_ppp0=( "pppoe" )
238 username_ppp0='user'
239 password_ppp0='password'
240 </pre>
241
242 <p>
243 You can also set your password in <path>/etc/ppp/pap-secrets</path>.
244 </p>
245
246 <pre caption="Sample /etc/ppp/pap-secrets">
247 <comment># The * is important</comment>
248 "username" * "password"
249 </pre>
250
251 <impo>
252 Please carefully read the section on ADSL and PPP in
253 <path>/etc/conf.d/net.example</path>. It contains many more detailed
254 explanations of all the settings your particular PPP setup will likely need.
255 </impo>
256
257 </body>
258 </section>
259 <section id="apipa">
260 <title>APIPA (Automatic Private IP Addressing)</title>
261 <body>
262
263 <p>
264 APIPA tries to find a free address in the range 169.254.0.0-169.254.255.255 by
265 arping a random address in that range on the interface. If no reply is found
266 then we assign that address to the interface.
267 </p>
268
269 <p>
270 This is only useful for LANs where there is no DHCP server and you don't connect
271 directly to the internet and all other computers use APIPA.
272 </p>
273
274 <p>
275 For APIPA support, emerge <c>net-misc/iputils</c> or <c>net-analyzer/arping</c>.
276 </p>
277
278 <pre caption="APIPA configuration in /etc/conf.d/net">
279 <comment># Try DHCP first - if that fails then fallback to APIPA</comment>
280 config_eth0=( "dhcp" )
281 fallback_eth0=( "apipa" )
282
283 <comment># Just use APIPA</comment>
284 config_eth0=( "apipa" )
285 </pre>
286
287 </body>
288 </section>
289 <section>
290 <title>Bonding</title>
291 <body>
292
293 <p>
294 For link bonding/trunking emerge <c>net-misc/ifenslave</c>.
295 </p>
296
297 <p>
298 Bonding is used to increase network bandwidth. If you have two network cards
299 going to the same network, you can bond them together so your applications see
300 just one interface but they really use both network cards.
301 </p>
302
303 <pre caption="bonding configuration in /etc/conf.d/net">
304 <comment># To bond interfaces together</comment>
305 slaves_bond0="eth0 eth1 eth2"
306
307 <comment># You may not want to assign an IP to the bonded interface</comment>
308 config_bond0=( "null" )
309
310 <comment># Depend on eth0, eth1 and eth2 as they may require extra configuration</comment>
311 depend_bond0() {
312 need net.eth0 net.eth1 net.eth2
313 }
314 </pre>
315
316 </body>
317 </section>
318 <section>
319 <title>Bridging (802.1d support)</title>
320 <body>
321
322 <p>
323 For bridging support emerge <c>net-misc/bridge-utils</c>.
324 </p>
325
326 <p>
327 Bridging is used to join networks together. For example, you may have a server
328 that connects to the internet via an ADSL modem and a wireless access card to
329 enable other computers to connect to the internet via the ADSL modem. You could
330 create a bridge to join the two interfaces together.
331 </p>
332
333 <pre caption="Bridge configuration in /etc/conf.d/net">
334 <comment># Configure the bridge - "man btctl" for more details</comment>
335 brctl_br0=( "setfd 0" "sethello 0" "stp off" )
336
337 <comment># To add ports to bridge br0</comment>
338 bridge_br0="eth0 eth1"
339
340 <comment># You need to configure the ports to null values so dhcp does not get started</comment>
341 config_eth0=( "null" )
342 config_eth1=( "null" )
343
344 <comment># Finally give the bridge an address - you could use DHCP as well</comment>
345 config_br0=( "192.168.0.1/24" )
346
347 <comment># Depend on eth0 and eth1 as they may require extra configuration</comment>
348 depend_br0() {
349 need net.eth0 net.eth1
350 }
351 </pre>
352
353 <impo>
354 For using some bridge setups, you may need to consult the <uri
355 link="?part=4&amp;chap=2#variable_name">variable name</uri> documentation.
356 </impo>
357
358 </body>
359 </section>
360 <section>
361 <title>MAC Address</title>
362 <body>
363
364 <p>
365 You don't need to emerge anything for changing the MAC address of your
366 interface if you have <c>sys-apps/baselayout-1.11.14</c> or newer and want to
367 change to a specific MAC address. However, if you need to change to a random MAC
368 address or have a baselayout older than the version mentioned above, you have
369 to emerge <c>net-analyzer/macchanger</c> to be able to make use of this feature.
370 </p>
371
372 <pre caption="MAC Address change example">
373 <comment># To set the MAC address of the interface</comment>
374 mac_eth0="00:11:22:33:44:55"
375
376 <comment># To randomize the last 3 bytes only</comment>
377 mac_eth0="random-ending"
378
379 <comment># To randomize between the same physical type of connection (e.g. fibre,
380 # copper, wireless) , all vendors</comment>
381 mac_eth0="random-samekind"
382
383 <comment># To randomize between any physical type of connection (e.g. fibre, copper,
384 # wireless) , all vendors</comment>
385 mac_eth0="random-anykind"
386
387 <comment># Full randomization - WARNING: some MAC addresses generated by this may
388 # NOT act as expected</comment>
389 mac_eth0="random-full"
390 </pre>
391
392 </body>
393 </section>
394 <section>
395 <title>Tunnelling</title>
396 <body>
397
398 <p>
399 You don't need to emerge anything for tunnelling as the interface handler can do
400 it for you.
401 </p>
402
403 <pre caption="Tunnelling configuration in /etc/conf.d/net">
404 <comment># For GRE tunnels</comment>
405 iptunnel_vpn0="mode gre remote 207.170.82.1 key 0xffffffff ttl 255"
406
407 <comment># For IPIP tunnels</comment>
408 iptunnel_vpn0="mode ipip remote 207.170.82.2 ttl 255"
409
410 <comment># To configure the interface</comment>
411 config_vpn0=( "192.168.0.2 peer 192.168.1.1" )
412 </pre>
413
414 </body>
415 </section>
416 <section>
417 <title>VLAN (802.1q support)</title>
418 <body>
419
420 <p>
421 For VLAN support, emerge <c>net-misc/vconfig</c>.
422 </p>
423
424 <p>
425 Virtual LAN is a group of network devices that behave as if they were connected
426 to a single network segment - even though they may not be. VLAN members can only
427 see members of the same VLAN even though they may share the same physical
428 network.
429 </p>
430
431 <pre caption="VLAN configuration in /etc/conf.d/net">
432 <comment># Specify the VLAN numbers for the interface like so</comment>
433 <comment># Please ensure your VLAN IDs are NOT zero-padded</comment>
434 vlans_eth0="1 2"
435
436 <comment># You can also configure the VLAN</comment>
437 <comment># see for vconfig man page for more details</comment>
438 vconfig_eth0=( "set_name_type VLAN_PLUS_VID_NO_PAD" )
439 vconfig_vlan1=( "set_flag 1" "set_egress_map 2 6" )
440
441 <comment># Configure the interface as usual</comment>
442 config_vlan1=( "172.16.3.1 netmask 255.255.254.0" )
443 config_vlan2=( "172.16.2.1 netmask 255.255.254.0" )
444 </pre>
445
446 <impo>
447 For using some VLAN setups, you may need to consult the <uri
448 link="?part=4&amp;chap=2#variable_name">variable name</uri> documentation.
449 </impo>
450
451 </body>
452 </section>
453
454 </sections>

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