1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
|
<!DOCTYPE html>
<html dir="ltr" lang="en">
<head>
<meta charset='utf-8'>
<title>2. Network</title>
</head>
<body>
<a href="index.html">Core OS Index</a>
<h1>2. Network</h1>
<p>Examples describe a network that will be configured with
two interfaces Ethernet and Wireless. Ethernet interface will
be configured as default route, wireless interface covered here
is simple alternative to Ethernet connection.</p>
<dl>
<dt><a href="conf/rc.d/net">/etc/rc.d/net</a></dt>
<dd>Configure Ethernet interface and static or dynamic (dhcp)
connection to the router and add as default gateway.</dd>
<dt><a href="conf/rc.d/wlan">/etc/rc.d/wlan</a></dt>
<dd>Configure Wireless interface, wpa_supplicant and dynamic (dhcp)
connection to router and add as default gateway.</dd>
</dl>
<p>If is first boot after install configure iptables and
one of above described scripts then proceed to upgrade your
system.</p>
<h2 id="resolv">2.1.1. Resolver</h2>
<p>This example will use
<a href="http://www.chaoscomputerclub.de/en/censorship/dns-howto">Chaos Computer Club</a>
server, edit /etc/resolv.conf and make it immutable;</p>
<pre>
# /etc/resolv.conf.head can replace this line
nameserver 213.73.91.35
# /etc/resolv.conf.tail can replace this line
</pre>
<pre>
# chattr +i /etc/resolv.conf
</pre>
<h2 id="static">2.1.2. Static IP</h2>
<p>Current example of <a href="conf/rc.d/net">/etc/rc.d/net</a>;</p>
<pre>
Address: 192.168.0.1 11000000.10101000.00000000 .00000001
Netmask: 255.255.255.0 = 24 11111111.11111111.11111111 .00000000
Wildcard: 0.0.0.255 00000000.00000000.00000000 .11111111
=>
Network: 192.168.0.0/24 11000000.10101000.00000000 .00000000 (Class C)
Broadcast: 192.168.0.255 11000000.10101000.00000000 .11111111
HostMin: 192.168.0.1 11000000.10101000.00000000 .00000001
HostMax: 192.168.0.254 11000000.10101000.00000000 .11111110
Hosts/Net: 254 (Private Internet)
</pre>
<p>Other IP class that can used for private network;</p>
<pre>
Address: 10.0.0.1 00001010.00000000.00000000 .00000001
Netmask: 255.255.255.0 = 24 11111111.11111111.11111111 .00000000
Wildcard: 0.0.0.255 00000000.00000000.00000000 .11111111
=>
Network: 10.0.0.0/24 00001010.00000000.00000000 .00000000 (Class A)
Broadcast: 10.0.0.255 00001010.00000000.00000000 .11111111
HostMin: 10.0.0.1 00001010.00000000.00000000 .00000001
HostMax: 10.0.0.254 00001010.00000000.00000000 .11111110
Hosts/Net: 254 (Private Internet)
</pre>
<p>Manual configuring like net script;</p>
<pre>
# DEV=enp8s0
# ADDR=192.168.1.9
# MASK=24
# GW=192.168.1.254
</pre>
<pre>
# ip addr flush dev ${DEV}
# ip route flush dev ${DEV}
# ip addr add ${ADDR}/${MASK} dev ${DEV} broadcast +
# ip link set ${DEV} up
# ip route add default via ${GW}
</pre>
<h2 id="iptables">2.1.3. Iptables</h2>
<p>For more information about iptables read
<a href="https://wiki.archlinux.org/index.php/Iptables">arch wiki</a>.
You can use
<a href="conf/iptables/rules.v4">/etc/iptables/rules.v4</a>
as template, replace interface by the one facing the router/gateway.
This configuration file is used at boot time by iptables-restore command,
if you use a script or change the rules of running system you can
use iptables-save command to save configuration to a file.</p>
<pre>
# mkdir /etc/iptables
# cp c9-doc/core/conf/iptables/rules.v4 /etc/iptables/
# cp c9-doc/core/conf/rc.d/iptables /etc/rc.d/
# chmod +x /etc/rc.d/iptables
</pre>
<p>Adjust rules.v4 to your needs, then;</p>
<pre>
# sh /etc/rc.d/iptables start
</pre>
<p>Copy init script, edit if you dont like to
let drop when you call stop.</p>
<p>Re-configure your rc.conf and add iptables before (w)lan is up;</p>
<pre>
SERVICES=(lo iptables net crond)
</pre>
<p>
<h2 id="wpa">2.1.4. Wpa and dhcpd</h2>
<p>There is more information on
<a href="http://crux.nu/Wiki/WifiStartScripts">Wiki Wifi Start Scripts</a> and
see <a href="conf/rc.d/wlan">/etc/rc.d/wlan</a>. Manual or first time configuration;</p>
<pre>
# ip link
</pre>
<pre>
# iwlist wlp2s0 scan
</pre>
<pre>
# iwconfig wlp2s0 essid NAME key s:ABCDE12345
</pre>
<h3>2.1.4.1. Wpa Supplicant</h3>
<p>Configure wpa supplicant edit;</p>
<pre>
# vim /etc/wpa_supplicant.conf
</pre>
<pre>
ctrl_interface=/var/run/wpa_supplicant
update_config=1
fast_reauth=1
ap_scan=1
</pre>
<pre>
# wpa_passphrase <ssid> <password> >> /etc/wpa_supplicant.conf
</pre>
<p>Now start wpa_supplicant with:</p>
<pre>
# wpa_supplicant -B -i wlp2s0 -c /etc/wpa_supplicant.conf
Successfully initialized wpa_supplicant
</pre>
<p>Use <a href="conf/rc.d/wlan">/etc/rc.d/wlan</a>
init script to auto load wpa configuration and dhcp
client.</p>
<h3>2.1.4.2. Wpa Cli</h3>
<pre>
# wpa_cli
> status
</pre>
<pre>
> add_network
3
</pre>
<pre>
> set_network 3 ssid "Crux-Network"
OK
</pre>
<pre>
> set_network 3 psk "uber-secret-pass"
OK
</pre>
<pre>
> enable_network 3
OK
</pre>
<pre>
> list_networks
</pre>
<pre>
> select_network 3
</pre>
<pre>
> save_config
</pre>
<h2 id="sysctl">2.1.5. Sysctl</h2>
<p>Sysctl references
<a href="https://wiki.archlinux.org/index.php/sysctl#TCP.2FIP_stack_hardening">Arch TCP/IP stack hardening</a>,
<a href="http://www.cyberciti.biz/tips/linux-unix-bsd-nginx-webserver-security.html">Cyberciti Nginx Hardning</a>,
<a href="http://www.cyberciti.biz/faq/linux-kernel-etcsysctl-conf-security-hardening/">Cyberciti Security Hardening</a>,
edit /etc/sysctl.conf;</p>
<pre>
#
# /etc/sysctl.conf: configuration for system variables, see sysctl.conf(5)
#
kernel.printk = 1 4 1 7
# Disable ipv6
net.ipv6.conf.all.disable_ipv6 = 1
net.ipv6.conf.default.disable_ipv6 = 1
net.ipv6.conf.lo.disable_ipv6 = 1
# Tuen IPv6
# net.ipv6.conf.default.router_solicitations = 0
# net.ipv6.conf.default.accept_ra_rtr_pref = 0
# net.ipv6.conf.default.accept_ra_pinfo = 0
# net.ipv6.conf.default.accept_ra_defrtr = 0
# net.ipv6.conf.default.autoconf = 0
# net.ipv6.conf.default.dad_transmits = 0
# net.ipv6.conf.default.max_addresses = 0
# Avoid a smurf attack
net.ipv4.icmp_echo_ignore_broadcasts = 1
# Turn on protection for bad icmp error messages
net.ipv4.icmp_ignore_bogus_error_responses = 1
# Turn on syncookies for SYN flood attack protection
net.ipv4.tcp_syncookies = 1
## protect against tcp time-wait assassination hazards
## drop RST packets for sockets in the time-wait state
## (not widely supported outside of linux, but conforms to RFC)
net.ipv4.tcp_rfc1337 = 1
## tcp timestamps
## + protect against wrapping sequence numbers (at gigabit speeds)
## + round trip time calculation implemented in TCP
## - causes extra overhead and allows uptime detection by scanners like nmap
## enable @ gigabit speeds
net.ipv4.tcp_timestamps = 0
#net.ipv4.tcp_timestamps = 1
# Turn on and log spoofed, source routed, and redirect packets
net.ipv4.conf.all.log_martians = 1
net.ipv4.conf.default.log_martians = 1
## ignore echo broadcast requests to prevent being part of smurf attacks (default)
net.ipv4.icmp_echo_ignore_broadcasts = 1
# No source routed packets here
net.ipv4.conf.all.accept_source_route = 0
net.ipv4.conf.default.accept_source_route = 0
## sets the kernels reverse path filtering mechanism to value 1(on)
## will do source validation of the packet's recieved from all the interfaces on the machine
## protects from attackers that are using ip spoofing methods to do harm
net.ipv4.conf.all.rp_filter = 1
net.ipv4.conf.default.rp_filter = 1
net.ipv6.conf.default.rp_filter = 1
net.ipv6.conf.all.rp_filter = 1
# Make sure no one can alter the routing tables
net.ipv4.conf.all.accept_redirects = 0
net.ipv4.conf.default.accept_redirects = 0
net.ipv4.conf.all.secure_redirects = 0
net.ipv4.conf.default.secure_redirects = 0
# Don't act as a router
net.ipv4.ip_forward = 0
net.ipv4.conf.all.send_redirects = 0
net.ipv4.conf.default.send_redirects = 0
kernel.shmmax = 500000000
# Turn on execshild
kernel.exec-shield = 1
kernel.randomize_va_space = 1
# Optimization for port usefor LBs
# Increase system file descriptor limit
fs.file-max = 65535
# Allow for more PIDs (to reduce rollover problems); may break some programs 32768
kernel.pid_max = 65536
# Increase system IP port limits
net.ipv4.ip_local_port_range = 2000 65000
# Increase TCP max buffer size setable using setsockopt()
net.ipv4.tcp_rmem = 4096 87380 8388608
net.ipv4.tcp_wmem = 4096 87380 8388608
# Increase Linux auto tuning TCP buffer limits
# min, default, and max number of bytes to use
# set max to at least 4MB, or higher if you use very high BDP paths
# Tcp Windows etc
net.core.rmem_max = 8388608
net.core.wmem_max = 8388608
net.core.netdev_max_backlog = 5000
net.ipv4.tcp_window_scaling = 1
# End of file
</pre>
<p>Change to act as a router (default of conf/sysctl.conf);</p>
<pre>
# Act as a router, necessary for Access Point
net.ipv4.ip_forward = 1
net.ipv4.conf.all.send_redirects = 1
net.ipv4.conf.default.send_redirects = 1
</pre>
<p>Load new settings;</p>
<pre>
# sysctl -p
</pre>
<a href="index.html">Core OS Index</a>
<p>
This is part of the c9-doc Manual.
Copyright (C) 2016
c9 team.
See the file <a href="../fdl-1.3-standalone.html">Gnu Free Documentation License</a>
for copying conditions.</p>
</body>
</html>
|