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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 1.18 2004/08/12 23:16:19 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 ddns-update-style ad-hoc;
310 subnet 192.168.0.0 netmask 255.255.255.0 {
311 range 192.168.0.100 192.168.0.250;
312 default-lease-time 259200;
313 max-lease-time 518400;
314 option subnet-mask 255.255.255.0;
315 option broadcast-address 192.168.0.255;
316 option routers 192.168.0.1;
317 option domain-name-servers 192.168.0.1;
318 }
319 </comment>
320 # <i>nano /etc/conf.d/dhcp</i>
321 <comment>Set IFACE="eth0"</comment>
322 # <i>rc-update add dhcp default</i>
323 # <i>/etc/init.d/dhcp start</i>
324 </pre>
325
326 <p>
327 Now your little router is a bona-fide DHCP server! Plugin those
328 computers and watch them work! With Windows systems you should go into
329 the TCP/IP Properties and select the 'Obtain an IP address
330 automatically' and 'Obtain DNS server address automatically' options.
331 Sometimes the changes aren't instantaneous, so you may have to run a
332 command prompt and run <c>ipconfig /release</c> and <c>ipconfig
333 /renew</c>. But enough about Windows, let's get back to our favorite
334 penguin.
335 </p>
336 </body>
337 </section>
338
339 <section>
340 <title>DNS Server</title>
341 <body>
342 <p>
343 When people want to visit a place on the internet, they remember names,
344 not a string of useless numbers. After all, what's easier to remember,
345 ebay.com or 66.135.192.87? This is where the DNS steps in. DNS servers
346 run all over the internet, and whenever someone wants to visit 'ebay.com',
347 these servers turn 'ebay.com' (what we understand) into '66.135.192.87'
348 (what our computers understand). For more information about DNS, you can
349 always visit <uri link="http://en.wikipedia.org/wiki/DNS">Wikipedia</uri>.
350 </p>
351
352 <p>
353 You may have noticed in the previous section that we told the DHCP
354 clients we have a DNS server at 192.168.0.1. You may also remember that
355 192.168.0.1 is our little router that we're making. I don't remember
356 setting up a DNS server ... so let's do so now!
357 </p>
358
359 <pre caption="Setting up dnsmasq">
360 # <i>emerge dnsmasq</i>
361 # <i>nano /etc/conf.d/dnsmasq</i>
362 <comment>Add "-i eth0" to DNSMASQ_OPTS</comment>
363 # <i>rc-update add dnsmasq default</i>
364 # <i>/etc/init.d/dnsmasq start</i>
365 </pre>
366
367 <p>
368 Well that was quick, but what did we do? The great thing is, we didn't
369 have to do very much! You're welcome to choose other DNS servers if
370 you're more comfortable with them, but the reason dnsmasq is great is
371 because it was designed to do exactly what we want and nothing more.
372 It's a little DNS caching/forwarding server for local networks. We're
373 not looking to provide DNS for our own domain here, just offer simple DNS
374 services to everyone else on our LAN.
375 </p>
376
377 </body>
378 </section>
379
380 <section>
381 <title>NAT (a.k.a. IP-masquerading)</title>
382 <body>
383
384 <p>
385 At this point, people on your network can talk to each other and they
386 can look up hostnames via DNS, but they still can't actually connect to
387 the internet. While you may think that's great (more bandwidth for
388 you!), I bet they're not too happy just yet.
389 </p>
390
391 <p>
392 This is where NAT steps in. NAT is a way of connecting multiple computers
393 in a private LAN to the internet when you only have a smaller number of
394 IP addresses availabe to you. Typically you were given 1 IP by your ISP,
395 but you want to let your whole house connect to the internet. NAT is the
396 magic that makes this possible. For more information about NAT, you can
397 always visit <uri link="http://en.wikipedia.org/wiki/NAT">Wikipedia</uri>.
398 </p>
399
400 <note>
401 Before we get started, make sure you have iptables on your system. Although
402 it is automatically installed on most systems, you may not have it. If you
403 don't, just run <c>emerge iptables</c>.
404 </note>
405
406 <pre caption="Setting up iptables">
407 <comment>First we flush our current rules</comment>
408 # <i>iptables -F</i>
409 # <i>iptables -t nat -F</i>
410
411 <comment>Then we lock our services so they only work from the LAN</comment>
412 # <i>iptables -I INPUT 1 -i eth0 -j ACCEPT</i>
413 # <i>iptables -I INPUT 1 -i lo -j ACCEPT</i>
414 # <i>iptables -A INPUT -p UDP --dport bootps -i ! eth0 -j REJECT</i>
415 # <i>iptables -A INPUT -p UDP --dport domain -i ! eth0 -j REJECT</i>
416
417 <comment>Drop TCP / UDP packets to privileged ports</comment>
418 # <i>iptables -A INPUT -p TCP -i ! eth0 -d 0/0 --dport 0:1023 -j DROP</i>
419 # <i>iptables -A INPUT -p UDP -i ! eth0 -d 0/0 --dport 0:1023 -j DROP</i>
420
421 <comment>Finally we add the rules for NAT</comment>
422 # <i>iptables -I FORWARD -i eth0 -d 192.168.0.0/255.255.0.0 -j DROP</i>
423 # <i>iptables -A FORWARD -i eth0 -s 192.168.0.0/255.255.0.0 -j ACCEPT</i>
424 # <i>iptables -A FORWARD -i eth1 -d 192.168.0.0/255.255.0.0 -j ACCEPT</i>
425 # <i>iptables -t nat -A POSTROUTING -o eth1 -j MASQUERADE</i>
426 <comment>Tell the kernel that ip forwarding is OK</comment>
427 # <i>echo 1 > /proc/sys/net/ipv4/ip_forward</i>
428 # <i>for f in /proc/sys/net/ipv4/conf/*/rp_filter ; do echo 1 > $f ; done</i>
429
430 <comment>This is so when we boot we don't have to run the rules by hand</comment>
431 # <i>/etc/init.d/iptables save</i>
432 # <i>rc-update add iptables default</i>
433 # <i>nano /etc/sysctl.conf</i>
434 <comment>Add/Uncomment the following lines:
435 net.ipv4.ip_forward = 1
436 net.ipv4.conf.default.rp_filter = 1</comment>
437 </pre>
438
439 <p>
440 Once you've typed out all of that, the rest of your network should now
441 be able to use the internet as if they were directly connected
442 themselves.
443 </p>
444
445 </body>
446 </section>
447 </chapter>
448
449 <chapter>
450 <title>Fun Things (for a rainy day)</title>
451
452 <section>
453 <title>Intro</title>
454 <body>
455 <p>
456 Believe it or not, you're done :). From here on out, I'll cover a bunch
457 of common topics that may interest you. Everything in this chapter is
458 completely optional.
459 </p>
460 </body>
461 </section>
462
463 <section>
464 <title>Port Forwarding</title>
465 <body>
466 <p>
467 Sometimes you would like to be able to host services on a computer behind
468 the router, or just to make your life easier when connecting remotely.
469 Perhaps you want to run a FTP, HTTP, SSH, or VNC server on one or more
470 machines behind your router and be able to connect to them all. The only
471 caveat is that you can only have one service/machine combo per port.
472 For example, there is no practical way to setup three FTP servers behind
473 your router and then try to connect to them all through port 21; only one
474 can be on port 21 while the others would have to be on say port 123 and
475 port 567.
476 </p>
477
478 <p>
479 All the port forwarding rules are of the form <c>iptables -t nat -A PREROUTING
480 [-p protocol] --dport [external port on router] -i eth1 -j DNAT --to [ip/port
481 to forward to]</c>. iptables does not accept hostnames when port forwarding.
482 If you are forwarding an external port to the same port on the internal machine,
483 you can omit the destination port. See the iptables(8) page for more information.
484 </p>
485
486 <pre>
487 <comment>Forward port 2 to ssh on an internal host</comment>
488 # <i>iptables -t nat -A PREROUTING -p tcp --dport 2 -i eth1 -j DNAT --to 192.168.0.2:22</i>
489
490 <comment>FTP forwarding to an internal host</comment>
491 # <i>iptables -t nat -A PREROUTING -p tcp --dport 21 -i eth1 -j DNAT --to 192.168.0.56</i>
492
493 <comment>HTTP forwarding to an internal host</comment>
494 # <i>iptables -t nat -A PREROUTING -p tcp --dport 80 -i eth1 -j DNAT --to 192.168.0.56</i>
495
496 <comment>VNC forwarding for internal hosts</comment>
497 # <i>iptables -t nat -I PREROUTING -p tcp --dport 5900 -i eth1 -j DNAT --to 192.168.0.2</i>
498 # <i>iptables -t nat -I PREROUTING -p tcp --dport 5901 -i eth1 -j DNAT --to 192.168.0.3:5900</i>
499 <comment>If you want to VNC in to 192.168.0.3, then just add ':1' to the router's hostname</comment>
500
501 <comment>Bittorrent forwarding</comment>
502 # <i>iptables -t nat -A PREROUTING -p tcp --dport 6881:6889 -i eth1 -j DNAT --to 192.168.0.2</i>
503
504 <comment>Game Cube Warp Pipe support</comment>
505 # <i>iptables -t nat -A PREROUTING -p udp --dport 4000 -i eth1 -j DNAT --to 192.168.0.56</i>
506
507 <comment>Playstation2 Online support</comment>
508 # <i>iptables -t nat -A PREROUTING -p tcp --dport 10070:10080 -i eth1 -j DNAT --to 192.168.0.11</i>
509 # <i>iptables -t nat -A PREROUTING -p udp --dport 10070:10080 -i eth1 -j DNAT --to 192.168.0.11</i>
510 </pre>
511
512 <note>
513 If you have other common / cool examples, please <uri link="mailto:vapier@gentoo.org">e-mail me</uri>.
514 </note>
515 </body>
516 </section>
517
518 <section>
519 <title>Identd (for IRC)</title>
520 <body>
521 <p>
522 Internet Relay Chat utilizes the ident service pretty heavily. Now that
523 the IRC clients are behind the router, we need a way to host ident for
524 both the router and the clients. One such server has been created
525 called <c>midentd</c>.
526 </p>
527
528 <pre caption="Setting up ident">
529 # <i>emerge midentd</i>
530 # <i>rc-update add midentd default</i>
531 # <i>/etc/init.d/midentd start</i>
532 </pre>
533
534 <p>
535 There are a few other ident servers in portage. Depending on your needs,
536 I would recommend checking out <c>oidentd</c> and <c>fakeidentd</c>.
537 </p>
538 </body>
539 </section>
540
541 <!--
542 <section>
543 <title>Traffic Shaping</title>
544 <body>
545 <p>
546 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>
547 found over at the TLDP. Feel free to refer to the original document
548 for more details.
549 </p>
550
551 <p>
552 Here we will be setting up what some people refer to as a "Packet Shaper",
553 <uri link="http://en.wikipedia.org/wiki/Traffic_shaping">"Traffic Shaping"</uri>,
554 or <uri link="http://en.wikipedia.org/wiki/QoS">"Quality of Service"</uri>.
555 Simply put, we want to setup rules on our router that will slow down
556 certain activities (like sending large e-mails or downloading from P2P
557 networks) while keeping other activities (like browsing the web or playing
558 online video games) reasonably fast. A 30 second difference in a video
559 game is a lot worse than a 30 second difference in downloading large
560 files :).
561 </p>
562
563 <p>
564 The first thing is to make sure your kernel has all the features added to
565 it. See the chapter on <uri link="#doc_chap2">Kernel setup</uri> for more
566 information. Next, you will need to <c>emerge iptables iputils</c> so that
567 you will have access to the <c>iptables</c>, <c>ip</c>, and <c>tc</c>
568 commands.
569 </p>
570
571 <p>
572 Before we jump into the commands, let's cover a little of the theory. The
573 way this whole system works is to classify common network streams and then
574 to prioritize them. You use iptables to classify network streams, iputils
575 to define the different priority levels, and the kernel to adjust speeds.
576 Just remember that although you can control outbound traffic pretty tightly
577 (from the LAN to the WAN), your ability to control inbound traffic (from
578 the WAN to the LAN) is somewhat limited. Just remember that the following
579 examples are to get your feet wet; if you want more then I'd suggest
580 reading up on the subject. In this example, we will be using the
581 <uri link="http://luxik.cdi.cz/~devik/qos/htb/">Hierarchical Token Buckets (HTB)</uri>
582 packet scheduling algorithm. Still with me? Great, let's start shaping :).
583 </p>
584
585 <pre caption="Setup">
586 DEV=eth1 <comment>NIC connected to WAN</comment>
587 RATE_OUT=100 <comment>Available outbound bandwidth (in kilobits [kb])</comment>
588 RATE_IN=1400 <comment>Available inbound bandwidth (in kb)</comment>
589
590 <comment>Here we initialize the priority system. The 45 is used to set the default classification level.</comment>
591 ip link set dev ${DEV} qlen 30
592 tc qdisc add dev ${DEV} root handle 1: htb default 45
593 tc class add dev ${DEV} parent 1: classid 1:1 htb rate ${RATE_OUT}kbit
594 </pre>
595
596 <p>
597 Here we initialized the system which will be used to prioritize all of
598 our network traffic. We created our queue, told it to use the HTB
599 algorithm, and set the default classification level to '45'. The
600 default is completely arbitrary, as are the levels we choose from
601 here on out. The only thing that matters is how the levels compare
602 relatively; a level '10' packet will be given preference over a
603 level '45' packet. Let's move on to declaring different levels.
604 </p>
605
606 <pre caption="Declaring levels">
607 tc class add dev $DEV parent 1:1 classid 1:10 htb rate $rkbit ceil $tkbit prio $p
608 tc qdisc add dev $DEV parent 1:10 handle 10: sfq
609 </pre>
610 </body>
611 </section>
612 -->
613
614 <section>
615 <title>Time Server</title>
616 <body>
617 <p>
618 Keeping your system time correct is essential in maintaing a healthy
619 system. One of the most common ways of accomplishing this is with
620 the Network Time Protocol (NTP) and the ntp package (which provides
621 implementations for both server and client).
622 </p>
623
624 <p>
625 Many people run ntp clients on their computers. Obviously, the more
626 clients in the world, the larger the load the ntp servers need to
627 shoulder. In environments like home networks though, we can help
628 keep the load down on public servers while still providing the proper
629 time to all our computers. As an added bonus, our private updates
630 will be a lot faster for the clients too! All we have to do is run
631 a ntp server on our router that synchronizes itself with the public
632 internet servers while providing the time to the rest of the computers
633 in the network. To get started, simply <c>emerge ntp</c> on the
634 router.
635 </p>
636
637 <pre caption="Setting up the NTP server">
638 # <i>nano /etc/conf.d/ntp-client</i>
639 <comment>Customize if you wish but the defaults should be fine</comment>
640 # <i>rc-update add ntp-client default</i>
641
642 # <i>nano /etc/ntp.conf</i>
643 <comment>Add the follwing lines:
644 restrict default ignore
645 restrict 192.168.0.0 mask 255.255.255.0 notrust nomodify notrap
646 These will allow only ntp clients with an IP address in the 192.168.0.xxx range to use your ntp server</comment>
647 # <i>nano /etc/conf.d/ntpd</i>
648 <comment>Customize if you wish but the defaults should be fine</comment>
649 # <i>rc-update add ntpd default</i>
650
651 # <i>/etc/init.d/ntp-client start</i>
652 # <i>/etc/init.d/ntpd start</i>
653 </pre>
654
655 <p>
656 Now, on your clients, have them <c>emerge ntp</c> also. However,
657 we will just run the ntp client so setup is a lot simpler.
658 </p>
659
660 <pre caption="Setting up a NTP client">
661 # <i>nano /etc/conf.d/ntp-client</i>
662 <comment>Change the 'pool.ntp.org' server in the NTPCLIENT_OPTS variable to '192.168.0.1'</comment>
663 # <i>rc-update add ntp-client default</i>
664 # <i>/etc/init.d/ntp-client start</i>
665 </pre>
666 </body>
667 </section>
668
669 <section>
670 <title>Mail Server</title>
671 <body>
672 <p>
673 Sometimes it's nice to run your own Simple Mail Transfer Protocol (SMTP)
674 server on the router. You may have your own reason for wanting to do so,
675 but I run it so that the users see mail as being sent instantly and the
676 work of retrying/routing is left up to the mail server. Some ISPs also
677 don't allow for mail relaying for accounts that aren't part of their
678 network (like Verizon). Also, you can easily throttle the delivery of
679 mail so that large attachments won't seriously lag your connection for
680 half an hour.
681 </p>
682
683 <pre caption="Setting up SMTP">
684 # <i>emerge qmail</i>
685 <comment>make sure the output of `hostname` is correct</comment>
686 # <i>ebuild /var/db/pkg/*-*/qmail-1.03-r*/*.ebuild config</i>
687 # <i>iptables -I INPUT -p tcp --dport smtp -i ! eth0 -j REJECT</i>
688 # <i>ln -s /var/qmail/supervise/qmail-send /service/qmail-send</i>
689 # <i>ln -s /var/qmail/supervise/qmail-smtpd /service/qmail-smtpd</i>
690 <!--
691 # <i>cd /etc/tcprules.d</i>
692 # <i>nano tcp.qmail-smtp</i>
693 -->
694 # <i>cd /etc</i>
695 # <i>nano tcp.smtp</i>
696 <comment>Add an entry like so to the allow section:
697 192.168.0.:allow,RELAYCLIENT=""</comment>
698 <!--
699 # <i>tcprules tcp.qmail-qmtp.cdb rules.tmp &lt; tcp.qmail-smtp</i>
700 -->
701 # <i>tcprules tcp.smtp.cdb rules.tmp &lt; tcp.smtp</i>
702 # <i>rc-update add svscan default</i>
703 # <i>/etc/init.d/svscan start</i>
704 </pre>
705
706 <p>
707 I'm a huge fan of qmail, but you're free to use a different mta :).
708 When you setup e-mail on the hosts in your network, tell them that
709 their SMTP server is 192.168.0.1 and everything should be peachy.
710 You might want to visit the <uri link="http://qmail.org/">qmail
711 homepage</uri> for more documentation.
712 </p>
713 </body>
714 </section>
715
716 <!--
717 <section>
718 <title>E-mail Virus Scanning</title>
719 <body>
720 <p>
721 If you'd like to provide e-mail virus scanning for your users, but
722 don't want to have to install a virus scanner on every single machine,
723 then <c>pop3vscan</c> may just be the thing for you; a transparent
724 Post Office Protocol (POP) scanner.
725 </p>
726
727 <pre caption="Setting up pop3vscan">
728 TODO
729 </pre>
730
731 </body>
732 </section>
733 -->
734
735 </chapter>
736
737 <chapter>
738 <title>Final Notes</title>
739 <section>
740 <body>
741 <p>
742 I have no final notes other than if you experience any troubles with the guide,
743 please contact <mail link="vapier@gentoo.org">me</mail> or file a bug with
744 <uri link="http://bugs.gentoo.org/">Gentoo's Bugtracking Website</uri>. If
745 you have some interesting bits you think would enhance this guide, by all means
746 send it my way for inclusion.
747 </p>
748 </body>
749 </section>
750 </chapter>
751 </guide>

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