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1 <?xml version='1.0' encoding='UTF-8'?>
2 <!-- $Header: /var/cvsroot/gentoo/xml/htdocs/doc/en/home-router-howto.xml,v 1.16 2004/08/12 04:50:52 vapier Exp $ -->
3 <!DOCTYPE guide SYSTEM "/dtd/guide.dtd">
4
5 <guide link="/doc/en/home-router-howto.xml">
6
7 <title>Home Router Guide</title>
8
9 <author title="Author">
10 <mail link="vapier@gentoo.org">Mike Frysinger</mail>
11 </author>
12
13 <abstract>
14 This document details how to turn an old Gentoo machine into a router
15 for connecting your home network to the internet.
16 </abstract>
17
18 <version>1.1</version>
19 <date>July 21, 2004</date>
20
21 <chapter>
22 <title>Introduction</title>
23 <section>
24 <body>
25
26 <p>
27 Building your own router out of old spare parts has many advantages
28 over buying a pre-made canned router by say Linksys. The biggest one by
29 far is control over the connection. The other advantages are left up to
30 your imagination; just about anything can be done in this scenario,
31 it's just a matter of needing it.
32 </p>
33
34 <p>
35 This guide will show you how to setup Network Address Translation (NAT)
36 on the router (kernel and iptables), add and configure common services
37 (Domain Name System (DNS) via dnsmasq, dhcp via dhcpcd, ADSL via
38 rp-pppoe), and conclude with more elaborate and fun things that can be
39 done (port forwarding, traffic shaping, proxies/caching, etc...).
40 </p>
41
42 <p>
43 Before getting started, there's a few basic requirements you must meet.
44 First, you'll need a computer that has at least 2 Network Interface
45 Cards (NICs) in it. Next, you'll need the configuration settings for
46 your internet connection (may include things like
47 IP/DNS/Gateway/username/password). Finally, you'll need a bit of spare
48 time and some Gentoo loving.
49 </p>
50
51 <p>
52 The conventions used in this guide are:
53 </p>
54 <ul>
55 <li>eth0 - NIC connected to the Local Area Network (LAN)</li>
56 <li>eth1 - NIC connected to the Wide Area Network (WAN)</li>
57 <li>LAN utilizes the private 192.168.0.xxx network</li>
58 <li>router is hardcoded to the standard 192.168.0.1 IP</li>
59 <li>router is running Linux 2.4 or 2.6; you're on your own with 2.0/2.2</li>
60 </ul>
61
62 <impo>
63 Due to security precautions, I would highly suggest you shut down any
64 unneeded services on the router until we have a chance to get the
65 firewall up and rolling. To view the currently running services, just
66 run <c>rc-status</c>.
67 </impo>
68
69 </body>
70 </section>
71 </chapter>
72
73 <chapter>
74 <title>Kernel setup (know thyself first)</title>
75 <section>
76 <body>
77
78 <p>
79 Your kernel needs to have the drivers running for both your NICs. To
80 see if your cards are already setup, just run <c>ifconfig</c>. Your
81 output may differ slightly from the following, that's fine. What
82 matters is that the interface shows up at all.
83 </p>
84 <pre caption="Checking NICs">
85 # <i>ifconfig -a</i>
86 eth0 Link encap:Ethernet HWaddr 00:60:F5:07:07:B8
87 BROADCAST MULTICAST MTU:1500 Metric:1
88 RX packets:0 errors:0 dropped:0 overruns:0 frame:0
89 TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
90 collisions:0 txqueuelen:1000
91 RX bytes:0 (0.0 b) TX bytes:0 (0.0 b)
92 Interrupt:11 Base address:0x9800
93
94 eth1 Link encap:Ethernet HWaddr 00:60:F5:07:07:B9
95 BROADCAST MULTICAST MTU:1500 Metric:1
96 RX packets:0 errors:0 dropped:0 overruns:0 frame:0
97 TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
98 collisions:0 txqueuelen:1000
99 RX bytes:0 (0.0 b) TX bytes:0 (0.0 b)
100 Interrupt:10 Base address:0x9400
101 </pre>
102 <p>
103 If you do not see your two cards showing up and you're not sure what
104 kind of cards you have, try running <c>lspci</c>. You can get that from
105 <c>emerge pciutils</c>. Look for "Ethernet controller" in the output.
106 Once you have this information, go into your kernel and add support for
107 the correct drivers.
108 </p>
109
110 <p>
111 The next thing you'll need is support for iptables and NAT (and packet
112 shaping if you want). The following list is split up into required
113 (*), suggested (x), and shaper (s) features. It does not matter whether
114 you build the features into the kernel or as a module so long as when
115 the feature is needed, the correct module(s) are loaded (module loading
116 is left to the reader as a fun exercise however).
117 </p>
118 <pre caption="Network Options">
119 <i>Networking options ---&gt;</i>
120 <i> [*] TCP/IP networking</i>
121 <i> [*] IP: advanced router</i>
122 <i> [*] Network packet filtering (replaces ipchains)</i>
123
124 <i> IP: Netfilter Configuration ---&gt;</i>
125 <i> [*] Connection tracking (required for masq/NAT)</i>
126 <i> [x] FTP protocol support</i>
127 <i> [x] IRC protocol support</i>
128 <i> [*] IP tables support (required for filtering/masq/NAT)</i>
129 <i> [*] IP range match support</i>
130 <i> [x] MAC address match support</i>
131 <i> [*] Multiple port match support</i>
132 <i> [*] Packet filtering</i>
133 <i> [*] REJECT target support</i>
134 <i> [x] REDIRECT target support</i>
135 <i> [*] Full NAT</i>
136 <i> [*] MASQUERADE target support</i>
137 <i> [s] Packet mangling</i>
138 <i> [s] MARK target support</i>
139 <i> [x] LOG target support</i>
140
141 <i> QoS and/or fair queueing ---&gt;</i>
142 <i> [s] QoS and/or fair queueing</i>
143 <i> [s] HTB packet scheduler</i>
144 <i> [s] Ingress Qdisc</i>
145 </pre>
146 <note>
147 Somethings may be slightly different in a 2.4 vs 2.6 kernel, but you
148 should be able to figure it out :).
149 </note>
150
151 </body>
152 </section>
153 </chapter>
154
155 <chapter>
156 <title>Hug the WAN (a.k.a. The Internet)</title>
157
158 <section>
159 <title>Intro</title>
160 <body>
161 <p>
162 There are many ways to connect to the internet so I'll just cover the
163 ones I'm familiar with. That leaves us with ADSL (PPPoE) and cable
164 modems (static/dynamic). If there are other methods out there, feel
165 free to write up a little blurb and e-mail me. Feel free to skip any of
166 the following sections in this chapter that don't apply to you. This
167 chapter is just about getting the router connected to the internet via
168 eth1.
169 </p>
170 </body>
171 </section>
172
173 <section>
174 <title>ADSL and PPPoE</title>
175 <body>
176
177 <p>
178 All the fancy PPPoE software has been bundled up into one little nice
179 package nowadays called <uri link="http://www.roaringpenguin.com/">Roaring Penguin</uri>.
180 Simply <c>emerge rp-pppoe</c> and you'll be on your way. Remember how
181 I said you'll need username/password information? Well I wasn't lying
182 so I hope you have it now! Load up <path>/etc/ppp/pppoe.conf</path> in
183 your favorite editor and set it up.
184 </p>
185
186 <note>
187 In order for the following net.eth1 settings to work, you must have
188 baselayout-1.10.1 or later installed on your system.
189 </note>
190
191 <pre caption="Setting up eth1">
192 <comment>(Replace 'vla9h924' with your username and 'password' with your password)</comment>
193
194 # <i>nano /etc/ppp/pppoe.conf</i>
195 <comment># Ethernet card connected to ADSL modem
196 ETH=eth1
197 # ADSL user name.
198 USER=vla9h924</comment>
199 # <i>nano /etc/ppp/pap-secrets</i>
200 <comment># client server secret
201 "vla9h924" * "password"</comment>
202 # <i>nano /etc/conf.d/net</i>
203 <comment>Add an entry for ifconfig_eth1 and set it to adsl:
204 ifconfig_eth1=( "adsl" )</comment>
205 # <i>ln -s net.eth0 /etc/init.d/net.eth1</i>
206 # <i>rc-update add net.eth1 default</i>
207 # <i>/etc/init.d/net.eth1 start</i>
208 </pre>
209
210 <warn>
211 When the DSL interface comes up, it will create ppp0. Although your NIC
212 is called eth1, the IP is actually bound to ppp0. From now on, when you
213 see examples that utilize 'eth1', substitute with 'ppp0'.
214 </warn>
215
216 </body>
217 </section>
218
219 <section>
220 <title>Cable and/or dynamic/static IP</title>
221 <body>
222
223 <p>
224 If you have a static IP then you will need a few more details than if
225 you have a dynamic IP. For static users, you will need your IP,
226 gateway, and DNS servers.
227 </p>
228
229 <pre caption="Setting up eth1">
230 <comment>Dynamic IP Users:</comment>
231 # <i>emerge dhcpcd</i>
232 # <i>nano /etc/conf.d/net</i>
233 <comment>You'll need an entry like so:
234 ifconfig_eth1=( "dhcp" )</comment>
235
236 <comment>Static IP Users:</comment>
237 # <i>nano /etc/conf.d/net</i>
238 <comment>You'll need entries like so:
239 ifconfig_eth1=( "66.92.78.102 broadcast 66.92.78.255 netmask 255.255.255.0" )
240 routes_eth1=( "default gw 66.92.78.1" )</comment>
241 # <i>nano /etc/resolv.conf</i>
242 <comment>Add one line per DNS server:
243 nameserver 123.123.123.123</comment>
244
245 <comment>Dynamic and Static Setup:</comment>
246 # <i>ln -s net.eth0 /etc/init.d/net.eth1</i>
247 # <i>rc-update add net.eth1 default</i>
248 # <i>/etc/init.d/net.eth1 start</i>
249 </pre>
250
251 <p>
252 You should be all set to go now.
253 </p>
254
255 </body>
256 </section>
257 </chapter>
258
259 <chapter>
260 <title>Hug the LAN (bring along some friends)</title>
261 <section>
262 <body>
263
264 <p>
265 This step is a breeze compared to the previous one.
266 </p>
267
268 <pre caption="Setting up eth0">
269 # <i>nano /etc/conf.d/net</i>
270 <comment>Add a line like the following:
271 ifconfig_eth0=( "192.168.0.1 broadcast 192.168.0.255 netmask 255.255.255.0" )</comment>
272 # <i>rc-update add net.eth0 default</i>
273 # <i>/etc/init.d/net.eth0 start</i>
274 </pre>
275
276 </body>
277 </section>
278 </chapter>
279
280 <chapter>
281 <title>LAN Services (because we're nice people)</title>
282
283 <section>
284 <title>DHCP Server</title>
285 <body>
286 <p>
287 I bet it'd be nice if everyone else in your house could just plug
288 their computers into the network and things would just work. No need to
289 remember mind-numbing details or make them stare at confusing
290 configuration screens! Life would be grand eh? Introducing the Dynamic
291 Host Configuration Protocol (DHCP) and why you should care.
292 </p>
293
294 <p>
295 DHCP is exactly what its name implies. It's a protocol that allows you
296 to dynamically configure other hosts automatically. You run a DHCP
297 server on the router (dhcpd), give it all the information about your
298 network (valid IPs, DNS servers, gateways, etc...), and then when the
299 other hosts start up, they run a DHCP client to automatically configure
300 themselves. No fuss, no muss! For more information about DHCP, you can
301 always visit <uri link="http://en.wikipedia.org/wiki/DHCP">Wikipedia</uri>.
302 </p>
303
304 <pre caption="Setting up dhcpd">
305 # <i>emerge dhcp</i>
306 # <i>nano /etc/dhcp/dhcpd.conf</i>
307 <comment>Here is a sample configuration file:
308 authoritative;
309 subnet 192.168.0.0 netmask 255.255.255.0 {
310 range 192.168.0.100 192.168.0.250;
311 default-lease-time 259200;
312 max-lease-time 518400;
313 option subnet-mask 255.255.255.0;
314 option broadcast-address 192.168.0.255;
315 option routers 192.168.0.1;
316 option domain-name-servers 192.168.0.1;
317 }
318 </comment>
319 # <i>nano /etc/conf.d/dhcp</i>
320 <comment>Set IFACE="eth0"</comment>
321 # <i>rc-update add dhcp default</i>
322 # <i>/etc/init.d/dhcp start</i>
323 </pre>
324
325 <p>
326 Now your little router is a bona-fide DHCP server! Plugin those
327 computers and watch them work! With Windows systems you should go into
328 the TCP/IP Properties and select the 'Obtain an IP address
329 automatically' and 'Obtain DNS server address automatically' options.
330 Sometimes the changes aren't instantaneous, so you may have to run a
331 command prompt and run <c>ipconfig /release</c> and <c>ipconfig
332 /renew</c>. But enough about Windows, let's get back to our favorite
333 penguin.
334 </p>
335 </body>
336 </section>
337
338 <section>
339 <title>DNS Server</title>
340 <body>
341 <p>
342 When people want to visit a place on the internet, they remember names,
343 not a string of useless numbers. After all, what's easier to remember,
344 ebay.com or 66.135.192.87? This is where the DNS steps in. DNS servers
345 run all over the internet, and whenever someone wants to visit 'ebay.com',
346 these servers turn 'ebay.com' (what we understand) into '66.135.192.87'
347 (what our computers understand). For more information about DNS, you can
348 always visit <uri link="http://en.wikipedia.org/wiki/DNS">Wikipedia</uri>.
349 </p>
350
351 <p>
352 You may have noticed in the previous section that we told the DHCP
353 clients we have a DNS server at 192.168.0.1. You may also remember that
354 192.168.0.1 is our little router that we're making. I don't remember
355 setting up a DNS server ... so let's do so now!
356 </p>
357
358 <pre caption="Setting up dnsmasq">
359 # <i>emerge dnsmasq</i>
360 # <i>nano /etc/conf.d/dnsmasq</i>
361 <comment>Add "-i eth1" to DNSMASQ_OPTS</comment>
362 # <i>rc-update add dnsmasq default</i>
363 # <i>/etc/init.d/dnsmasq start</i>
364 </pre>
365
366 <p>
367 Well that was quick, but what did we do? The great thing is, we didn't
368 have to do very much! You're welcome to choose other DNS servers if
369 you're more comfortable with them, but the reason dnsmasq is great is
370 because it was designed to do exactly what we want and nothing more.
371 It's a little DNS caching/forwarding server for local networks. We're
372 not looking to provide DNS for our own domain here, just offer simple DNS
373 services to everyone else on our LAN.
374 </p>
375
376 </body>
377 </section>
378
379 <section>
380 <title>NAT (a.k.a. IP-masquerading)</title>
381 <body>
382
383 <p>
384 At this point, people on your network can talk to each other and they
385 can look up hostnames via DNS, but they still can't actually connect to
386 the internet. While you may think that's great (more bandwidth for
387 you!), I bet they're not too happy just yet.
388 </p>
389
390 <p>
391 This is where NAT steps in. NAT is a way of connecting multiple computers
392 in a private LAN to the internet when you only have a smaller number of
393 IP addresses availabe to you. Typically you were given 1 IP by your ISP,
394 but you want to let your whole house connect to the internet. NAT is the
395 magic that makes this possible. For more information about NAT, you can
396 always visit <uri link="http://en.wikipedia.org/wiki/NAT">Wikipedia</uri>.
397 </p>
398
399 <note>
400 Before we get started, make sure you have iptables on your system. Although
401 it is automatically installed on most systems, you may not have it. If you
402 don't, just run <c>emerge iptables</c>.
403 </note>
404
405 <pre caption="Setting up iptables">
406 <comment>First we flush our current rules</comment>
407 # <i>iptables -F</i>
408 # <i>iptables -t nat -F</i>
409
410 <comment>Then we lock our services so they only work from the LAN</comment>
411 # <i>iptables -I INPUT 1 -i eth0 -j ACCEPT</i>
412 # <i>iptables -I INPUT 1 -i lo -j ACCEPT</i>
413 # <i>iptables -A INPUT -p UDP --dport bootps -i ! eth0 -j REJECT</i>
414 # <i>iptables -A INPUT -p UDP --dport domain -i ! eth0 -j REJECT</i>
415
416 <comment>Drop TCP / UDP packets to privileged ports</comment>
417 # <i>iptables -A INPUT -p TCP -i ! eth0 -d 0/0 --dport 0:1023 -j DROP</i>
418 # <i>iptables -A INPUT -p UDP -i ! eth0 -d 0/0 --dport 0:1023 -j DROP</i>
419
420 <comment>Finally we add the rules for NAT</comment>
421 # <i>iptables -I FORWARD -i eth0 -d 192.168.0.0/255.255.0.0 -j DROP</i>
422 # <i>iptables -A FORWARD -i eth0 -s 192.168.0.0/255.255.0.0 -j ACCEPT</i>
423 # <i>iptables -A FORWARD -i eth1 -d 192.168.0.0/255.255.0.0 -j ACCEPT</i>
424 # <i>iptables -t nat -A POSTROUTING -o eth1 -j MASQUERADE</i>
425 <comment>Tell the kernel that ip forwarding is OK</comment>
426 # <i>echo 1 > /proc/sys/net/ipv4/ip_forward</i>
427 # <i>for f in /proc/sys/net/ipv4/conf/*/rp_filter ; do echo 1 > $f ; done</i>
428
429 <comment>This is so when we boot we don't have to run the rules by hand</comment>
430 # <i>/etc/init.d/iptables save</i>
431 # <i>rc-update add iptables default</i>
432 # <i>nano /etc/sysctl.conf</i>
433 <comment>Add/Uncomment the following lines:
434 net.ipv4.ip_forward = 1
435 net.ipv4.conf.default.rp_filter = 1</comment>
436 </pre>
437
438 <p>
439 Once you've typed out all of that, the rest of your network should now
440 be able to use the internet as if they were directly connected
441 themselves.
442 </p>
443
444 </body>
445 </section>
446 </chapter>
447
448 <chapter>
449 <title>Fun Things (for a rainy day)</title>
450
451 <section>
452 <title>Intro</title>
453 <body>
454 <p>
455 Believe it or not, you're done :). From here on out, I'll cover a bunch
456 of common topics that may interest you. Everything in this chapter is
457 completely optional.
458 </p>
459 </body>
460 </section>
461
462 <section>
463 <title>Port Forwarding</title>
464 <body>
465 <p>
466 Sometimes you would like to be able to host services on a computer behind
467 the router, or just to make your life easier when connecting remotely.
468 Perhaps you want to run a FTP, HTTP, SSH, or VNC server on one or more
469 machines behind your router and be able to connect to them all. The only
470 caveat is that you can only have one service/machine combo per port.
471 For example, there is no practical way to setup three FTP servers behind
472 your router and then try to connect to them all through port 21; only one
473 can be on port 21 while the others would have to be on say port 123 and
474 port 567.
475 </p>
476
477 <p>
478 All the port forwarding rules are of the form <c>iptables -t nat -A PREROUTING
479 [-p protocol] --dport [external port on router] -i eth1 -j DNAT --to [ip/port
480 to forward to]</c>. iptables does not accept hostnames when port forwarding.
481 If you are forwarding an external port to the same port on the internal machine,
482 you can omit the destination port. See the iptables(8) page for more information.
483 </p>
484
485 <pre>
486 <comment>Forward port 2 to ssh on an internal host</comment>
487 # <i>iptables -t nat -A PREROUTING -p tcp --dport 2 -i eth1 -j DNAT --to 192.168.0.2:22</i>
488
489 <comment>FTP forwarding to an internal host</comment>
490 # <i>iptables -t nat -A PREROUTING -p tcp --dport 21 -i eth1 -j DNAT --to 192.168.0.56</i>
491
492 <comment>HTTP forwarding to an internal host</comment>
493 # <i>iptables -t nat -A PREROUTING -p tcp --dport 80 -i eth1 -j DNAT --to 192.168.0.56</i>
494
495 <comment>VNC forwarding for internal hosts</comment>
496 # <i>iptables -t nat -I PREROUTING -p tcp --dport 5900 -i eth1 -j DNAT --to 192.168.0.2</i>
497 # <i>iptables -t nat -I PREROUTING -p tcp --dport 5901 -i eth1 -j DNAT --to 192.168.0.3:5900</i>
498 <comment>If you want to VNC in to 192.168.0.3, then just add ':1' to the router's hostname</comment>
499
500 <comment>Bittorrent forwarding</comment>
501 # <i>iptables -t nat -A PREROUTING -p tcp --dport 6881:6889 -i eth1 -j DNAT --to 192.168.0.2</i>
502
503 <comment>Game Cube Warp Pipe support</comment>
504 # <i>iptables -t nat -A PREROUTING -p udp --dport 4000 -i eth1 -j DNAT --to 192.168.0.56</i>
505
506 <comment>Playstation2 Online support</comment>
507 # <i>iptables -t nat -A PREROUTING -p tcp --dport 10070:10080 -i eth1 -j DNAT --to 192.168.0.11</i>
508 # <i>iptables -t nat -A PREROUTING -p udp --dport 10070:10080 -i eth1 -j DNAT --to 192.168.0.11</i>
509 </pre>
510
511 <note>
512 If you have other common / cool examples, please <uri link="mailto:vapier@gentoo.org">e-mail me</uri>.
513 </note>
514 </body>
515 </section>
516
517 <section>
518 <title>Identd (for IRC)</title>
519 <body>
520 <p>
521 Internet Relay Chat utilizes the ident service pretty heavily. Now that
522 the IRC clients are behind the router, we need a way to host ident for
523 both the router and the clients. One such server has been created
524 called <c>midentd</c>.
525 </p>
526
527 <pre caption="Setting up ident">
528 # <i>emerge midentd</i>
529 # <i>rc-update add midentd default</i>
530 # <i>/etc/init.d/midentd start</i>
531 </pre>
532
533 <p>
534 There are a few other ident servers in portage. Depending on your needs,
535 I would recommend checking out <c>oidentd</c> and <c>fakeidentd</c>.
536 </p>
537 </body>
538 </section>
539
540 <!--
541 <section>
542 <title>Traffic Shaping</title>
543 <body>
544 <p>
545 This is an attempt to simply and Gentooify the <uri link="http://www.tldp.org/HOWTO/ADSL-Bandwidth-Management-HOWTO/">ADSL Bandwidth Management HOWTO</uri>
546 found over at the TLDP. Feel free to refer to the original document
547 for more details.
548 </p>
549
550 <p>
551 Here we will be setting up what some people refer to as a "Packet Shaper",
552 <uri link="http://en.wikipedia.org/wiki/Traffic_shaping">"Traffic Shaping"</uri>,
553 or <uri link="http://en.wikipedia.org/wiki/QoS">"Quality of Service"</uri>.
554 Simply put, we want to setup rules on our router that will slow down
555 certain activities (like sending large e-mails or downloading from P2P
556 networks) while keeping other activities (like browsing the web or playing
557 online video games) reasonably fast. A 30 second difference in a video
558 game is a lot worse than a 30 second difference in downloading large
559 files :).
560 </p>
561
562 <p>
563 The first thing is to make sure your kernel has all the features added to
564 it. See the chapter on <uri link="#doc_chap2">Kernel setup</uri> for more
565 information. Next, you will need to <c>emerge iptables iputils</c> so that
566 you will have access to the <c>iptables</c>, <c>ip</c>, and <c>tc</c>
567 commands.
568 </p>
569
570 <p>
571 Before we jump into the commands, let's cover a little of the theory. The
572 way this whole system works is to classify common network streams and then
573 to prioritize them. You use iptables to classify network streams, iputils
574 to define the different priority levels, and the kernel to adjust speeds.
575 Just remember that although you can control outbound traffic pretty tightly
576 (from the LAN to the WAN), your ability to control inbound traffic (from
577 the WAN to the LAN) is somewhat limited. Just remember that the following
578 examples are to get your feet wet; if you want more then I'd suggest
579 reading up on the subject. In this example, we will be using the
580 <uri link="http://luxik.cdi.cz/~devik/qos/htb/">Hierarchical Token Buckets (HTB)</uri>
581 packet scheduling algorithm. Still with me? Great, let's start shaping :).
582 </p>
583
584 <pre caption="Setup">
585 DEV=eth1 <comment>NIC connected to WAN</comment>
586 RATE_OUT=100 <comment>Available outbound bandwidth (in kilobits [kb])</comment>
587 RATE_IN=1400 <comment>Available inbound bandwidth (in kb)</comment>
588
589 <comment>Here we initialize the priority system. The 45 is used to set the default classification level.</comment>
590 ip link set dev ${DEV} qlen 30
591 tc qdisc add dev ${DEV} root handle 1: htb default 45
592 tc class add dev ${DEV} parent 1: classid 1:1 htb rate ${RATE_OUT}kbit
593 </pre>
594
595 <p>
596 Here we initialized the system which will be used to prioritize all of
597 our network traffic. We created our queue, told it to use the HTB
598 algorithm, and set the default classification level to '45'. The
599 default is completely arbitrary, as are the levels we choose from
600 here on out. The only thing that matters is how the levels compare
601 relatively; a level '10' packet will be given preference over a
602 level '45' packet. Let's move on to declaring different levels.
603 </p>
604
605 <pre caption="Declaring levels">
606 tc class add dev $DEV parent 1:1 classid 1:10 htb rate $rkbit ceil $tkbit prio $p
607 tc qdisc add dev $DEV parent 1:10 handle 10: sfq
608 </pre>
609 </body>
610 </section>
611 -->
612
613 <section>
614 <title>Time Server</title>
615 <body>
616 <p>
617 Keeping your system time correct is essential in maintaing a healthy
618 system. One of the most common ways of accomplishing this is with
619 the Network Time Protocol (NTP) and the ntp package (which provides
620 implementations for both server and client).
621 </p>
622
623 <p>
624 Many people run ntp clients on their computers. Obviously, the more
625 clients in the world, the larger the load the ntp servers need to
626 shoulder. In environments like home networks though, we can help
627 keep the load down on public servers while still providing the proper
628 time to all our computers. As an added bonus, our private updates
629 will be a lot faster for the clients too! All we have to do is run
630 a ntp server on our router that synchronizes itself with the public
631 internet servers while providing the time to the rest of the computers
632 in the network. To get started, simply <c>emerge ntp</c> on the
633 router.
634 </p>
635
636 <pre caption="Setting up the NTP server">
637 # <i>nano /etc/conf.d/ntp-client</i>
638 <comment>Customize if you wish but the defaults should be fine</comment>
639 # <i>rc-update add ntp-client default</i>
640
641 # <i>nano /etc/ntp.conf</i>
642 <comment>Add the follwing lines:
643 restrict default ignore
644 restrict 192.168.0.0 mask 255.255.255.0 notrust nomodify notrap
645 These will allow only ntp clients with an IP address in the 192.168.0.xxx range to use your ntp server</comment>
646 # <i>nano /etc/conf.d/ntpd</i>
647 <comment>Customize if you wish but the defaults should be fine</comment>
648 # <i>rc-update add ntpd default</i>
649
650 # <i>/etc/init.d/ntp-client start</i>
651 # <i>/etc/init.d/ntpd start</i>
652 </pre>
653
654 <p>
655 Now, on your clients, have them <c>emerge ntp</c> also. However,
656 we will just run the ntp client so setup is a lot simpler.
657 </p>
658
659 <pre caption="Setting up a NTP client">
660 # <i>nano /etc/conf.d/ntp-client</i>
661 <comment>Change the 'pool.ntp.org' server in the NTPCLIENT_OPTS variable to '192.168.0.1'</comment>
662 # <i>rc-update add ntp-client default</i>
663 # <i>/etc/init.d/ntp-client start</i>
664 </pre>
665 </body>
666 </section>
667
668 <section>
669 <title>Mail Server</title>
670 <body>
671 <p>
672 Sometimes it's nice to run your own Simple Mail Transfer Protocol (SMTP)
673 server on the router. You may have your own reason for wanting to do so,
674 but I run it so that the users see mail as being sent instantly and the
675 work of retrying/routing is left up to the mail server. Some ISPs also
676 don't allow for mail relaying for accounts that aren't part of their
677 network (like Verizon). Also, you can easily throttle the delivery of
678 mail so that large attachments won't seriously lag your connection for
679 half an hour.
680 </p>
681
682 <pre caption="Setting up SMTP">
683 # <i>emerge qmail</i>
684 <comment>make sure the output of `hostname` is correct</comment>
685 # <i>ebuild /var/db/pkg/*-*/qmail-1.03-r*/*.ebuild config</i>
686 # <i>iptables -I INPUT -p tcp --dport smtp -i ! eth0 -j REJECT</i>
687 # <i>ln -s /var/qmail/supervise/qmail-send /service/qmail-send</i>
688 # <i>ln -s /var/qmail/supervise/qmail-smtpd /service/qmail-smtpd</i>
689 <!--
690 # <i>cd /etc/tcprules.d</i>
691 # <i>nano tcp.qmail-smtp</i>
692 -->
693 # <i>cd /etc</i>
694 # <i>nano tcp.smtp</i>
695 <comment>Add an entry like so to the allow section:
696 192.168.0.:allow,RELAYCLIENT=""</comment>
697 <!--
698 # <i>tcprules tcp.qmail-qmtp.cdb rules.tmp &lt; tcp.qmail-smtp</i>
699 -->
700 # <i>tcprules tcp.smtp.cdb rules.tmp &lt; tcp.smtp</i>
701 # <i>rc-update add svscan default</i>
702 # <i>/etc/init.d/svscan start</i>
703 </pre>
704
705 <p>
706 I'm a huge fan of qmail, but you're free to use a different mta :).
707 When you setup e-mail on the hosts in your network, tell them that
708 their SMTP server is 192.168.0.1 and everything should be peachy.
709 You might want to visit the <uri link="http://qmail.org/">qmail
710 homepage</uri> for more documentation.
711 </p>
712 </body>
713 </section>
714
715 <!--
716 <section>
717 <title>E-mail Virus Scanning</title>
718 <body>
719 <p>
720 If you'd like to provide e-mail virus scanning for your users, but
721 don't want to have to install a virus scanner on every single machine,
722 then <c>pop3vscan</c> may just be the thing for you; a transparent
723 Post Office Protocol (POP) scanner.
724 </p>
725
726 <pre caption="Setting up pop3vscan">
727 TODO
728 </pre>
729
730 </body>
731 </section>
732 -->
733
734 </chapter>
735
736 <chapter>
737 <title>Final Notes</title>
738 <section>
739 <body>
740 <p>
741 I have no final notes other than if you experience any troubles with the guide,
742 please contact <mail link="vapier@gentoo.org">me</mail> or file a bug with
743 <uri link="http://bugs.gentoo.org/">Gentoo's Bugtracking Website</uri>. If
744 you have some interesting bits you think would enhance this guide, by all means
745 send it my way for inclusion.
746 </p>
747 </body>
748 </section>
749 </chapter>
750 </guide>

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