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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 1.21 2004/09/22 19:03:58 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>1.3</version>
19 <date>Feb 15 2005</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 <comment>If you use 2.4.x, you have to enable the following for DHCP:</comment>
124 <i> [*] Socket Filtering</i>
125
126 <i> IP: Netfilter Configuration ---&gt;</i>
127 <i> [*] Connection tracking (required for masq/NAT)</i>
128 <i> [x] FTP protocol support</i>
129 <i> [x] IRC protocol support</i>
130 <i> [*] IP tables support (required for filtering/masq/NAT)</i>
131 <i> [*] IP range match support</i>
132 <i> [x] MAC address match support</i>
133 <i> [*] Multiple port match support</i>
134 <i> [*] Packet filtering</i>
135 <i> [*] REJECT target support</i>
136 <i> [x] REDIRECT target support</i>
137 <i> [*] Full NAT</i>
138 <i> [*] MASQUERADE target support</i>
139 <i> [s] Packet mangling</i>
140 <i> [s] MARK target support</i>
141 <i> [x] LOG target support</i>
142
143 <i> QoS and/or fair queueing ---&gt;</i>
144 <i> [s] QoS and/or fair queueing</i>
145 <i> [s] HTB packet scheduler</i>
146 <i> [s] Ingress Qdisc</i>
147 </pre>
148 <note>
149 Somethings may be slightly different in a 2.4 vs 2.6 kernel, but you
150 should be able to figure it out :).
151 </note>
152
153 </body>
154 </section>
155 </chapter>
156
157 <chapter>
158 <title>Hug the WAN (a.k.a. The Internet)</title>
159
160 <section>
161 <title>Intro</title>
162 <body>
163 <p>
164 There are many ways to connect to the internet so I'll just cover the
165 ones I'm familiar with. That leaves us with ADSL (PPPoE) and cable
166 modems (static/dynamic). If there are other methods out there, feel
167 free to write up a little blurb and e-mail me. Feel free to skip any of
168 the following sections in this chapter that don't apply to you. This
169 chapter is just about getting the router connected to the internet via
170 eth1.
171 </p>
172 </body>
173 </section>
174
175 <section>
176 <title>ADSL and PPPoE</title>
177 <body>
178
179 <p>
180 All the fancy PPPoE software has been bundled up into one little nice
181 package nowadays called <uri link="http://www.roaringpenguin.com/">Roaring Penguin</uri>.
182 Simply <c>emerge rp-pppoe</c> and you'll be on your way. Remember how
183 I said you'll need username/password information? Well I wasn't lying
184 so I hope you have it now! Load up <path>/etc/ppp/pppoe.conf</path> in
185 your favorite editor and set it up.
186 </p>
187
188 <note>
189 In order for the following net.eth1 settings to work, you must have
190 baselayout-1.10.1 or later installed on your system.
191 </note>
192
193 <pre caption="Setting up eth1">
194 <comment>(Replace 'vla9h924' with your username and 'password' with your password)</comment>
195
196 # <i>nano /etc/ppp/pppoe.conf</i>
197 <comment># Ethernet card connected to ADSL modem
198 ETH=eth1
199 # ADSL user name.
200 USER=vla9h924</comment>
201 # <i>nano /etc/ppp/pap-secrets</i>
202 <comment># client server secret
203 "vla9h924" * "password"</comment>
204 # <i>nano /etc/conf.d/net</i>
205 <comment>Add an entry for ifconfig_eth1 and set it to adsl:
206 ifconfig_eth1=( "adsl" )</comment>
207 # <i>ln -s net.eth0 /etc/init.d/net.eth1</i>
208 # <i>rc-update add net.eth1 default</i>
209 # <i>/etc/init.d/net.eth1 start</i>
210 </pre>
211
212 <warn>
213 When the DSL interface comes up, it will create ppp0. Although your NIC
214 is called eth1, the IP is actually bound to ppp0. From now on, when you
215 see examples that utilize 'eth1', substitute with 'ppp0'.
216 </warn>
217
218 </body>
219 </section>
220
221 <section>
222 <title>Cable and/or dynamic/static IP</title>
223 <body>
224
225 <p>
226 If you have a static IP then you will need a few more details than if
227 you have a dynamic IP. For static users, you will need your IP,
228 gateway, and DNS servers.
229 </p>
230
231 <pre caption="Setting up eth1">
232 <comment>Dynamic IP Users:</comment>
233 # <i>emerge dhcpcd</i>
234 # <i>nano /etc/conf.d/net</i>
235 <comment>You'll need an entry like so:
236 ifconfig_eth1=( "dhcp" )</comment>
237
238 <comment>Static IP Users:</comment>
239 # <i>nano /etc/conf.d/net</i>
240 <comment>You'll need entries like so:
241 ifconfig_eth1=( "66.92.78.102 broadcast 66.92.78.255 netmask 255.255.255.0" )
242 routes_eth1=( "default gw 66.92.78.1" )</comment>
243 # <i>nano /etc/resolv.conf</i>
244 <comment>Add one line per DNS server:
245 nameserver 123.123.123.123</comment>
246
247 <comment>Dynamic and Static Setup:</comment>
248 # <i>ln -s net.eth0 /etc/init.d/net.eth1</i>
249 # <i>rc-update add net.eth1 default</i>
250 # <i>/etc/init.d/net.eth1 start</i>
251 </pre>
252
253 <p>
254 You should be all set to go now.
255 </p>
256
257 </body>
258 </section>
259 </chapter>
260
261 <chapter>
262 <title>Hug the LAN (bring along some friends)</title>
263 <section>
264 <body>
265
266 <p>
267 This step is a breeze compared to the previous one.
268 </p>
269
270 <pre caption="Setting up eth0">
271 # <i>nano /etc/conf.d/net</i>
272 <comment>Add a line like the following:
273 ifconfig_eth0=( "192.168.0.1 broadcast 192.168.0.255 netmask 255.255.255.0" )</comment>
274 # <i>rc-update add net.eth0 default</i>
275 # <i>/etc/init.d/net.eth0 start</i>
276 </pre>
277
278 </body>
279 </section>
280 </chapter>
281
282 <chapter>
283 <title>LAN Services (because we're nice people)</title>
284
285 <section>
286 <title>DHCP Server</title>
287 <body>
288 <p>
289 I bet it'd be nice if everyone else in your house could just plug
290 their computers into the network and things would just work. No need to
291 remember mind-numbing details or make them stare at confusing
292 configuration screens! Life would be grand eh? Introducing the Dynamic
293 Host Configuration Protocol (DHCP) and why you should care.
294 </p>
295
296 <p>
297 DHCP is exactly what its name implies. It's a protocol that allows you
298 to dynamically configure other hosts automatically. You run a DHCP
299 server on the router (dhcpd), give it all the information about your
300 network (valid IPs, DNS servers, gateways, etc...), and then when the
301 other hosts start up, they run a DHCP client to automatically configure
302 themselves. No fuss, no muss! For more information about DHCP, you can
303 always visit <uri link="http://en.wikipedia.org/wiki/DHCP">Wikipedia</uri>.
304 </p>
305
306 <pre caption="Setting up dhcpd">
307 # <i>emerge dhcp</i>
308 # <i>nano /etc/dhcp/dhcpd.conf</i>
309 <comment>Here is a sample configuration file:
310 authoritative;
311 ddns-update-style ad-hoc;
312 subnet 192.168.0.0 netmask 255.255.255.0 {
313 range 192.168.0.100 192.168.0.250;
314 default-lease-time 259200;
315 max-lease-time 518400;
316 option subnet-mask 255.255.255.0;
317 option broadcast-address 192.168.0.255;
318 option routers 192.168.0.1;
319 option domain-name-servers 192.168.0.1;
320 }
321 </comment>
322 # <i>nano /etc/conf.d/dhcp</i>
323 <comment>Set IFACE="eth0"</comment>
324 # <i>rc-update add dhcp default</i>
325 # <i>/etc/init.d/dhcp start</i>
326 </pre>
327
328 <p>
329 Now your little router is a bona-fide DHCP server! Plugin those
330 computers and watch them work! With Windows systems you should go into
331 the TCP/IP Properties and select the 'Obtain an IP address
332 automatically' and 'Obtain DNS server address automatically' options.
333 Sometimes the changes aren't instantaneous, so you may have to run a
334 command prompt and run <c>ipconfig /release</c> and <c>ipconfig
335 /renew</c>. But enough about Windows, let's get back to our favorite
336 penguin.
337 </p>
338 </body>
339 </section>
340
341 <section>
342 <title>DNS Server</title>
343 <body>
344 <p>
345 When people want to visit a place on the internet, they remember names,
346 not a string of useless numbers. After all, what's easier to remember,
347 ebay.com or 66.135.192.87? This is where the DNS steps in. DNS servers
348 run all over the internet, and whenever someone wants to visit 'ebay.com',
349 these servers turn 'ebay.com' (what we understand) into '66.135.192.87'
350 (what our computers understand). For more information about DNS, you can
351 always visit <uri link="http://en.wikipedia.org/wiki/DNS">Wikipedia</uri>.
352 </p>
353
354 <p>
355 You may have noticed in the previous section that we told the DHCP
356 clients we have a DNS server at 192.168.0.1. You may also remember that
357 192.168.0.1 is our little router that we're making. I don't remember
358 setting up a DNS server ... so let's do so now!
359 </p>
360
361 <pre caption="Setting up dnsmasq">
362 # <i>emerge dnsmasq</i>
363 # <i>nano /etc/conf.d/dnsmasq</i>
364 <comment>Add "-i eth0" to DNSMASQ_OPTS</comment>
365 # <i>rc-update add dnsmasq default</i>
366 # <i>/etc/init.d/dnsmasq start</i>
367 </pre>
368
369 <p>
370 Well that was quick, but what did we do? The great thing is, we didn't
371 have to do very much! You're welcome to choose other DNS servers if
372 you're more comfortable with them, but the reason dnsmasq is great is
373 because it was designed to do exactly what we want and nothing more.
374 It's a little DNS caching/forwarding server for local networks. We're
375 not looking to provide DNS for our own domain here, just offer simple DNS
376 services to everyone else on our LAN.
377 </p>
378
379 </body>
380 </section>
381
382 <section>
383 <title>NAT (a.k.a. IP-masquerading)</title>
384 <body>
385
386 <p>
387 At this point, people on your network can talk to each other and they
388 can look up hostnames via DNS, but they still can't actually connect to
389 the internet. While you may think that's great (more bandwidth for
390 you!), I bet they're not too happy just yet.
391 </p>
392
393 <p>
394 This is where NAT steps in. NAT is a way of connecting multiple computers
395 in a private LAN to the internet when you only have a smaller number of
396 IP addresses availabe to you. Typically you were given 1 IP by your ISP,
397 but you want to let your whole house connect to the internet. NAT is the
398 magic that makes this possible. For more information about NAT, you can
399 always visit <uri link="http://en.wikipedia.org/wiki/NAT">Wikipedia</uri>.
400 </p>
401
402 <note>
403 Before we get started, make sure you have iptables on your system. Although
404 it is automatically installed on most systems, you may not have it. If you
405 don't, just run <c>emerge iptables</c>.
406 </note>
407
408 <pre caption="Setting up iptables">
409 <comment>First we flush our current rules</comment>
410 # <i>iptables -F</i>
411 # <i>iptables -t nat -F</i>
412
413 <comment>Then we lock our services so they only work from the LAN</comment>
414 # <i>iptables -I INPUT 1 -i eth0 -j ACCEPT</i>
415 # <i>iptables -I INPUT 1 -i lo -j ACCEPT</i>
416 # <i>iptables -A INPUT -p UDP --dport bootps -i ! eth0 -j REJECT</i>
417 # <i>iptables -A INPUT -p UDP --dport domain -i ! eth0 -j REJECT</i>
418
419 <comment>(Optional) Allow access to our ssh server from the WAN</comment>
420 # <i>iptables -A INPUT -p TCP --dport ssh -i eth1 -j ACCEPT</i>
421
422 <comment>Drop TCP / UDP packets to privileged ports</comment>
423 # <i>iptables -A INPUT -p TCP -i ! eth0 -d 0/0 --dport 0:1023 -j DROP</i>
424 # <i>iptables -A INPUT -p UDP -i ! eth0 -d 0/0 --dport 0:1023 -j DROP</i>
425
426 <comment>Finally we add the rules for NAT</comment>
427 # <i>iptables -I FORWARD -i eth0 -d 192.168.0.0/255.255.0.0 -j DROP</i>
428 # <i>iptables -A FORWARD -i eth0 -s 192.168.0.0/255.255.0.0 -j ACCEPT</i>
429 # <i>iptables -A FORWARD -i eth1 -d 192.168.0.0/255.255.0.0 -j ACCEPT</i>
430 # <i>iptables -t nat -A POSTROUTING -o eth1 -j MASQUERADE</i>
431 <comment>Tell the kernel that ip forwarding is OK</comment>
432 # <i>echo 1 > /proc/sys/net/ipv4/ip_forward</i>
433 # <i>for f in /proc/sys/net/ipv4/conf/*/rp_filter ; do echo 1 > $f ; done</i>
434
435 <comment>This is so when we boot we don't have to run the rules by hand</comment>
436 # <i>/etc/init.d/iptables save</i>
437 # <i>rc-update add iptables default</i>
438 # <i>nano /etc/sysctl.conf</i>
439 <comment>Add/Uncomment the following lines:
440 net.ipv4.ip_forward = 1
441 net.ipv4.conf.default.rp_filter = 1</comment>
442 </pre>
443
444 <p>
445 Once you've typed out all of that, the rest of your network should now
446 be able to use the internet as if they were directly connected
447 themselves.
448 </p>
449
450 </body>
451 </section>
452 </chapter>
453
454 <chapter>
455 <title>Fun Things (for a rainy day)</title>
456
457 <section>
458 <title>Intro</title>
459 <body>
460 <p>
461 Believe it or not, you're done :). From here on out, I'll cover a bunch
462 of common topics that may interest you. Everything in this chapter is
463 completely optional.
464 </p>
465 </body>
466 </section>
467
468 <section>
469 <title>Port Forwarding</title>
470 <body>
471 <p>
472 Sometimes you would like to be able to host services on a computer behind
473 the router, or just to make your life easier when connecting remotely.
474 Perhaps you want to run a FTP, HTTP, SSH, or VNC server on one or more
475 machines behind your router and be able to connect to them all. The only
476 caveat is that you can only have one service/machine combo per port.
477 For example, there is no practical way to setup three FTP servers behind
478 your router and then try to connect to them all through port 21; only one
479 can be on port 21 while the others would have to be on say port 123 and
480 port 567.
481 </p>
482
483 <p>
484 All the port forwarding rules are of the form <c>iptables -t nat -A PREROUTING
485 [-p protocol] --dport [external port on router] -i eth1 -j DNAT --to [ip/port
486 to forward to]</c>. iptables does not accept hostnames when port forwarding.
487 If you are forwarding an external port to the same port on the internal machine,
488 you can omit the destination port. See the iptables(8) page for more information.
489 </p>
490
491 <pre>
492 <comment>Forward port 2 to ssh on an internal host</comment>
493 # <i>iptables -t nat -A PREROUTING -p tcp --dport 2 -i eth1 -j DNAT --to 192.168.0.2:22</i>
494
495 <comment>FTP forwarding to an internal host</comment>
496 # <i>iptables -t nat -A PREROUTING -p tcp --dport 21 -i eth1 -j DNAT --to 192.168.0.56</i>
497
498 <comment>HTTP forwarding to an internal host</comment>
499 # <i>iptables -t nat -A PREROUTING -p tcp --dport 80 -i eth1 -j DNAT --to 192.168.0.56</i>
500
501 <comment>VNC forwarding for internal hosts</comment>
502 # <i>iptables -t nat -I PREROUTING -p tcp --dport 5900 -i eth1 -j DNAT --to 192.168.0.2</i>
503 # <i>iptables -t nat -I PREROUTING -p tcp --dport 5901 -i eth1 -j DNAT --to 192.168.0.3:5900</i>
504 <comment>If you want to VNC in to 192.168.0.3, then just add ':1' to the router's hostname</comment>
505
506 <comment>Bittorrent forwarding</comment>
507 # <i>iptables -t nat -A PREROUTING -p tcp --dport 6881:6889 -i eth1 -j DNAT --to 192.168.0.2</i>
508
509 <comment>Game Cube Warp Pipe support</comment>
510 # <i>iptables -t nat -A PREROUTING -p udp --dport 4000 -i eth1 -j DNAT --to 192.168.0.56</i>
511
512 <comment>Playstation2 Online support</comment>
513 # <i>iptables -t nat -A PREROUTING -p tcp --dport 10070:10080 -i eth1 -j DNAT --to 192.168.0.11</i>
514 # <i>iptables -t nat -A PREROUTING -p udp --dport 10070:10080 -i eth1 -j DNAT --to 192.168.0.11</i>
515 </pre>
516
517 <note>
518 If you have other common / cool examples, please <uri link="mailto:vapier@gentoo.org">e-mail me</uri>.
519 </note>
520 </body>
521 </section>
522
523 <section>
524 <title>Identd (for IRC)</title>
525 <body>
526 <p>
527 Internet Relay Chat utilizes the ident service pretty heavily. Now that
528 the IRC clients are behind the router, we need a way to host ident for
529 both the router and the clients. One such server has been created
530 called <c>midentd</c>.
531 </p>
532
533 <pre caption="Setting up ident">
534 # <i>emerge midentd</i>
535 # <i>rc-update add midentd default</i>
536 # <i>/etc/init.d/midentd start</i>
537 </pre>
538
539 <p>
540 There are a few other ident servers in portage. Depending on your needs,
541 I would recommend checking out <c>oidentd</c> and <c>fakeidentd</c>.
542 </p>
543 </body>
544 </section>
545
546 <!--
547 <section>
548 <title>Traffic Shaping</title>
549 <body>
550 <p>
551 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>
552 found over at the TLDP. Feel free to refer to the original document
553 for more details.
554 </p>
555
556 <p>
557 Here we will be setting up what some people refer to as a "Packet Shaper",
558 <uri link="http://en.wikipedia.org/wiki/Traffic_shaping">"Traffic Shaping"</uri>,
559 or <uri link="http://en.wikipedia.org/wiki/QoS">"Quality of Service"</uri>.
560 Simply put, we want to setup rules on our router that will slow down
561 certain activities (like sending large e-mails or downloading from P2P
562 networks) while keeping other activities (like browsing the web or playing
563 online video games) reasonably fast. A 30 second difference in a video
564 game is a lot worse than a 30 second difference in downloading large
565 files :).
566 </p>
567
568 <p>
569 The first thing is to make sure your kernel has all the features added to
570 it. See the chapter on <uri link="#doc_chap2">Kernel setup</uri> for more
571 information. Next, you will need to <c>emerge iptables iputils</c> so that
572 you will have access to the <c>iptables</c>, <c>ip</c>, and <c>tc</c>
573 commands.
574 </p>
575
576 <p>
577 Before we jump into the commands, let's cover a little of the theory. The
578 way this whole system works is to classify common network streams and then
579 to prioritize them. You use iptables to classify network streams, iputils
580 to define the different priority levels, and the kernel to adjust speeds.
581 Just remember that although you can control outbound traffic pretty tightly
582 (from the LAN to the WAN), your ability to control inbound traffic (from
583 the WAN to the LAN) is somewhat limited. Just remember that the following
584 examples are to get your feet wet; if you want more then I'd suggest
585 reading up on the subject. In this example, we will be using the
586 <uri link="http://luxik.cdi.cz/~devik/qos/htb/">Hierarchical Token Buckets (HTB)</uri>
587 packet scheduling algorithm. Still with me? Great, let's start shaping :).
588 </p>
589
590 <pre caption="Setup">
591 DEV=eth1 <comment>NIC connected to WAN</comment>
592 RATE_OUT=100 <comment>Available outbound bandwidth (in kilobits [kb])</comment>
593 RATE_IN=1400 <comment>Available inbound bandwidth (in kb)</comment>
594
595 <comment>Here we initialize the priority system. The 45 is used to set the default classification level.</comment>
596 ip link set dev ${DEV} qlen 30
597 tc qdisc add dev ${DEV} root handle 1: htb default 45
598 tc class add dev ${DEV} parent 1: classid 1:1 htb rate ${RATE_OUT}kbit
599 </pre>
600
601 <p>
602 Here we initialized the system which will be used to prioritize all of
603 our network traffic. We created our queue, told it to use the HTB
604 algorithm, and set the default classification level to '45'. The
605 default is completely arbitrary, as are the levels we choose from
606 here on out. The only thing that matters is how the levels compare
607 relatively; a level '10' packet will be given preference over a
608 level '45' packet. Let's move on to declaring different levels.
609 </p>
610
611 <pre caption="Declaring levels">
612 tc class add dev $DEV parent 1:1 classid 1:10 htb rate $rkbit ceil $tkbit prio $p
613 tc qdisc add dev $DEV parent 1:10 handle 10: sfq
614 </pre>
615 </body>
616 </section>
617 -->
618
619 <section>
620 <title>Time Server</title>
621 <body>
622 <p>
623 Keeping your system time correct is essential in maintaing a healthy
624 system. One of the most common ways of accomplishing this is with
625 the Network Time Protocol (NTP) and the ntp package (which provides
626 implementations for both server and client).
627 </p>
628
629 <p>
630 Many people run ntp clients on their computers. Obviously, the more
631 clients in the world, the larger the load the ntp servers need to
632 shoulder. In environments like home networks though, we can help
633 keep the load down on public servers while still providing the proper
634 time to all our computers. As an added bonus, our private updates
635 will be a lot faster for the clients too! All we have to do is run
636 a ntp server on our router that synchronizes itself with the public
637 internet servers while providing the time to the rest of the computers
638 in the network. To get started, simply <c>emerge ntp</c> on the
639 router.
640 </p>
641
642 <pre caption="Setting up the NTP server">
643 # <i>nano /etc/conf.d/ntp-client</i>
644 <comment>Customize if you wish but the defaults should be fine</comment>
645 # <i>rc-update add ntp-client default</i>
646
647 # <i>nano /etc/ntp.conf</i>
648 <comment>Add the follwing lines:
649 restrict default ignore
650 restrict 192.168.0.0 mask 255.255.255.0 notrust nomodify notrap
651 These will allow only ntp clients with an IP address in the 192.168.0.xxx range to use your ntp server</comment>
652 # <i>nano /etc/conf.d/ntpd</i>
653 <comment>Customize if you wish but the defaults should be fine</comment>
654 # <i>rc-update add ntpd default</i>
655
656 # <i>/etc/init.d/ntp-client start</i>
657 # <i>/etc/init.d/ntpd start</i>
658 </pre>
659
660 <note>
661 You should make sure that you allow inbound and outbound communication
662 on the ntp port (123/udp) when setting up the server. The client just
663 needs outbound access on port 123 over udp.
664 </note>
665
666 <p>
667 Now, on your clients, have them <c>emerge ntp</c> also. However,
668 we will just run the ntp client so setup is a lot simpler.
669 </p>
670
671 <pre caption="Setting up a NTP client">
672 # <i>nano /etc/conf.d/ntp-client</i>
673 <comment>Change the 'pool.ntp.org' server in the NTPCLIENT_OPTS variable to '192.168.0.1'</comment>
674 # <i>rc-update add ntp-client default</i>
675 # <i>/etc/init.d/ntp-client start</i>
676 </pre>
677 </body>
678 </section>
679
680 <section>
681 <title>Mail Server</title>
682 <body>
683 <p>
684 Sometimes it's nice to run your own Simple Mail Transfer Protocol (SMTP)
685 server on the router. You may have your own reason for wanting to do so,
686 but I run it so that the users see mail as being sent instantly and the
687 work of retrying/routing is left up to the mail server. Some ISPs also
688 don't allow for mail relaying for accounts that aren't part of their
689 network (like Verizon). Also, you can easily throttle the delivery of
690 mail so that large attachments won't seriously lag your connection for
691 half an hour.
692 </p>
693
694 <pre caption="Setting up SMTP">
695 # <i>emerge qmail</i>
696 <comment>make sure the output of `hostname` is correct</comment>
697 # <i>ebuild /var/db/pkg/*-*/qmail-1.03-r*/*.ebuild config</i>
698 # <i>iptables -I INPUT -p tcp --dport smtp -i ! eth0 -j REJECT</i>
699 # <i>ln -s /var/qmail/supervise/qmail-send /service/qmail-send</i>
700 # <i>ln -s /var/qmail/supervise/qmail-smtpd /service/qmail-smtpd</i>
701 <!--
702 # <i>cd /etc/tcprules.d</i>
703 # <i>nano tcp.qmail-smtp</i>
704 -->
705 # <i>cd /etc</i>
706 # <i>nano tcp.smtp</i>
707 <comment>Add an entry like so to the allow section:
708 192.168.0.:allow,RELAYCLIENT=""</comment>
709 <!--
710 # <i>tcprules tcp.qmail-qmtp.cdb rules.tmp &lt; tcp.qmail-smtp</i>
711 -->
712 # <i>tcprules tcp.smtp.cdb rules.tmp &lt; tcp.smtp</i>
713 # <i>rc-update add svscan default</i>
714 # <i>/etc/init.d/svscan start</i>
715 </pre>
716
717 <p>
718 I'm a huge fan of qmail, but you're free to use a different mta :).
719 When you setup e-mail on the hosts in your network, tell them that
720 their SMTP server is 192.168.0.1 and everything should be peachy.
721 You might want to visit the <uri link="http://qmail.org/">qmail
722 homepage</uri> for more documentation.
723 </p>
724 </body>
725 </section>
726
727 <!--
728 <section>
729 <title>E-mail Virus Scanning</title>
730 <body>
731 <p>
732 If you'd like to provide e-mail virus scanning for your users, but
733 don't want to have to install a virus scanner on every single machine,
734 then <c>pop3vscan</c> may just be the thing for you; a transparent
735 Post Office Protocol (POP) scanner.
736 </p>
737
738 <pre caption="Setting up pop3vscan">
739 TODO
740 </pre>
741
742 </body>
743 </section>
744 -->
745
746 </chapter>
747
748 <chapter>
749 <title>Final Notes</title>
750 <section>
751 <body>
752 <p>
753 I have no final notes other than if you experience any troubles with the guide,
754 please contact <mail link="vapier@gentoo.org">me</mail> or file a bug with
755 <uri link="http://bugs.gentoo.org/">Gentoo's Bugtracking Website</uri>. If
756 you have some interesting bits you think would enhance this guide, by all means
757 send it my way for inclusion.
758 </p>
759 </body>
760 </section>
761 </chapter>
762 </guide>

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